Human Performance as a Building Design Requirement

Prepared for Blend Technology

Research paper for owners, architects, interior designers and engineering teams

5 September 2026 Pacific time

Executive finding

A building establishes conditions that people live with for hours every day. Its light reaches their eyes, its mechanical systems move the air they breathe, its surfaces and equipment shape what they hear, and its controls determine how much attention basic activities require. Research shows that some of these conditions can alter sleep, alertness, task performance, respiratory comfort, physiological responses and reported mood. These effects are relevant to the project vision because the decisions that create them begin with layout, envelope, materials, service space and system selection.

The resulting design requirement is concrete: identify the human activities the project should support, translate them into measurable environmental conditions, assign responsibility across disciplines, and verify those conditions in operation. ASHRAE’s 2025 position on human health and wellness supports a lifecycle approach to occupant health and interdisciplinary collaboration. This paper develops a practical application of that principle; it is an evidence review and design proposal, not a clinical validation of a complete Blend installation. ASHRAE 2025

The evidence is strongest for specific exposure and outcome pairs. Light can change circadian timing and alertness. Environmental noise can cause physiological sleep disruption. Accumulated indoor pollutants and bioeffluents can contribute to symptoms and impaired performance under studied conditions. Dampness and mould are associated with respiratory illness. Noise can interfere with speech and concentration. These findings justify deliberate specification even when the benefit for an individual occupant cannot be predicted precisely. Brown et al 2022 Basner et al 2011 Zhang et al 2017 WHO dampness guidance 2009 Picou et al 2016

The important distinction is between a condition the project can deliver and a human outcome it hopes to support. A team can commit to tested airflow, controlled nighttime light, defined acoustic performance, moisture management and usable controls. It cannot responsibly guarantee a percentage increase in cognition, a particular sleep stage, freedom from headaches or a clinical recovery time. This distinction makes the work accountable without stripping it of its purpose.

For Blend, the opportunity is to make human requirements explicit across the project: which exposures are relevant, which decisions influence them, how competing systems will be coordinated, and how the result will be measured. Acoustic modeling, environmental sensing and control design become useful through that connection. Their value is the condition delivered to the person using the room.

This paper’s targets are drawn from established, cited science, not from outcomes observed on Blend’s own projects. The argument is not that Blend has discovered a formula; it is that a defensible standard already exists: scientifically supported targets, applied through the intentional design of a building’s structure, systems and materials, to optimize human performance. Decades of research support that these systems affect human conditions individually. Little to no research addresses them designed together, as one system, which is the reason careful coordination is a design responsibility rather than a claim to new science. Blend is a design firm, not a research firm. It applies existing evidence to design decisions, builds in manual override and ongoing adjustment as occupants settle into a space, and would welcome contributing project data to outside researchers rather than treating that data as its own validation.

How to use this paper

Sections 1 through 8 establish the evidence across human outcomes and environmental domains. Sections 9 through 12 translate it into schematic decisions, MEPT deliverables, performance schedules and verification. Section 13 identifies priorities and open questions. The source notes retain study titles, dates and links, followed by an index of the internal research consulted.

MEPT means mechanical, electrical, plumbing and technology in this paper. Architecture, interiors, envelope and acoustics remain essential participants. The main applications are residences, hospitality and workplaces. School and healthcare studies are included where they illuminate mechanisms or design needs; their results are not automatically transferred to healthy adults at home.

What counts as evidence

Controlled human experiments can establish effects of the exposure actually tested. Their limitations often include small samples, short durations, artificial tasks or unusual exposure levels. Field interventions provide useful evidence under more realistic conditions, but frequently change several environmental variables at once. Observational studies reveal patterns across real populations; they cannot fully separate environmental effects from behavior, socioeconomic conditions, illness or other exposures. Animal and laboratory mechanisms can explain plausibility but cannot establish a human building intervention’s benefit.

This review uses three practical descriptions. Established or well supported means that a mechanism or bounded exposure effect has substantial support. Supported with limits means the evidence is credible but population, context, measurement or causality restricts the claim. Emerging means the hypothesis deserves investigation or an optional trial, without becoming a promised project outcome. These are narrative judgments, not a formal GRADE assessment.

This paper’s evidence is published research, not outcomes observed on Blend’s own projects; project experience is not treated as scientific support anywhere in this review. The one exception is Particle, Blend’s acoustic modeling tool. Its subwoofer placement, first- and second-order reflection point locations, wall-material reverberation-time estimate and room geometry outputs are verified against field measurement, running consistently within specification, and are therefore treated as validated design inputs rather than anecdote. That verification is specific to those outputs and does not extend to any other tool, product or claim discussed in this paper.

Symptoms also require precision. “Brain fog” is an occupant description, not one standardized outcome. Studies may instead measure reaction time, attention, working memory, thinking difficulty or fatigue. Mood, annoyance, diagnosed depression and physiological stress markers are different endpoints. “Recovery” may mean feeling rested, resuming work or recovering from a medical procedure; the evidence for one does not prove another. Persistent symptoms can have multiple causes, so environmental assessment complements appropriate clinical evaluation.

Map of addressable impacts

The following map summarizes the evidence developed in the cited sections. It distinguishes immediate experience, measured function and longer term biological risk. Design implications are the synthesis of this paper.

Why unnoticed effects are a credible concern

A person’s impression of a room does not fully describe its exposure. Brief awakenings may not be remembered. Maintained task scores can coexist with worse mood or greater physiological arousal. A comfortable temperature reading does not describe glare, intrusive sound or pollutant accumulation. These are reasons to investigate the actual conditions rather than dismiss a concern because the room looks finished or the occupant cannot identify the source. They are not evidence that every concealed technology is harmful. Basner and McGuire 2018 Sander et al 2021

The design question is therefore specific: which modifiable conditions in this room could reasonably burden the activity it is intended to support, and what would demonstrate that those conditions were addressed?

Light exposure has a biological timing function

Light influences circadian physiology through exposure at the eye. Spectrum, intensity, timing and duration matter. Conventional task-plane illuminance, correlated color temperature and color rendering do not independently describe this exposure. CIE recommends appropriate metrology and coordination of visual needs with nonvisual effects, architecture, glare and energy considerations. CIE 2024

Individual sensitivity varies substantially. In a controlled study of 55 healthy participants, Phillips and colleagues found large differences in evening melatonin response; some participants responded strongly at much lower light levels than others. Melatonin suppression is a physiological measure, not interchangeable with deep-sleep loss or a disease outcome. The practical implication is adequate adjustment range and attention to exposure at occupied positions, rather than one fixed color or brightness recipe for everyone. Phillips et al 2019

Brown and colleagues provide an actionable consensus for healthy adults aged 18-55 with regular daytime schedules. The recommendations use melanopic equivalent daylight illuminance, a measure of light relevant to melanopsin-weighted responses, assessed at the eye. They are research-informed recommendations rather than building code or guaranteed individual thresholds. Brown et al 2022

These values are not ordinary horizontal lux limits. Safety, individual needs, age and schedule can require a different brief. A warm-colored lamp alone does not establish compliance.

Screens and room light produce measurable effects under tested conditions

Chang and colleagues studied 12 healthy young adults in a randomized crossover experiment comparing light-emitting tablet reading with print reading over five evenings per condition. Approximately four hours of evening tablet exposure delayed circadian timing, lengthened sleep latency, changed REM sleep and reduced next-morning alertness. REM is distinct from N3, the sleep stage commonly called deep sleep. This study supports including displays in the evening exposure inventory; it does not establish the same effect from a brief interaction or every status LED. Chang et al 2015

Mason and colleagues randomized 20 healthy adults to room light or dim conditions during sleep. One night at 100 photopic lux, compared with less than 3 lux, increased sleeping heart rate and altered next-morning insulin resistance. The experiment demonstrates acute physiological effects at that exposure. It does not establish that a tiny indicator causes diabetes or that bedroom darkness prevents metabolic disease. Exterior spill, corridor leakage and equipment output nevertheless belong in a complete nighttime lighting assessment. Mason et al 2022

Sound can disturb sleep without a dramatic remembered awakening

Controlled transportation-noise research using polysomnography, which records physiological sleep stages, shows changes in sleep and reported recuperation. Basner and colleagues found relatively small changes in whole-night sleep structure and mostly unchanged next-day objective performance, despite poorer subjective sleep. The result is more specific than a claim that noise destroys all restorative sleep. Event timing and characteristics matter, so an average sound reading alone can miss the relevant exposure. Basner et al 2011

In a laboratory study of 12 volunteers, Buxton and colleagues presented hospital sounds during defined sleep stages. Arousal depended on level, sound type and sleep stage; electronic sounds were particularly arousing. The tested hospital sounds cannot be equated with every domestic device, but they make nighttime beeps, confirmation tones, switching events and unnecessary notifications legitimate design subjects. Required life-safety audibility must remain intact. Buxton et al 2012

Nighttime noise also has physiological evidence beyond reported annoyance. In a randomized home study of 75 healthy adults, aircraft-noise playback impaired a measure of vascular function and increased epinephrine. Cortisol and several other measures did not change. This supports attention to nighttime exposure without converting an acute experiment into a claim that acoustic treatment prevents cardiovascular events. Schmidt et al 2013

Adding sound is not automatically a sleep intervention. A 2026 polysomnographic trial of 25 healthy adults found that the tested environmental noise reduced N3 sleep, while tested pink noise reduced REM. Morning cognitive measures were unchanged. The conditions and doses do not represent every sound machine, but they argue for controlling the source and transmission path before prescribing continuous nighttime masking. Basner et al 2026

Mechanical cycling is a sleep exposure to remediate

A mechanical system can meet a steady operating sound criterion yet introduce intrusive changes when it starts, stops or changes capacity. Stanchina and colleagues recorded 1,178 sleep arousals in a small laboratory experiment using recorded ICU noise. Four participants completed all three conditions and one completed two. The reported background-to-peak differences associated with arousals were approximately 17.7 and 17.5 dB in the two noise conditions. The authors identified the change above background as more informative than peak level alone. Those values are observations from that experiment, not a permissible HVAC excursion or a universal REM threshold. Stanchina et al 2005

The Sound Sleep Study report provides a direct mechanical-design connection: its laboratory preparation recommended vibration isolation and continuous rather than intermittent heat-pump operation to reduce sound changes. This was a measure to control the laboratory environment, not a trial establishing a safe cycling threshold. Together, these sources support explicitly addressing mechanical transitions in sleep-space design. They do not justify increasing background noise or running every fan continuously regardless of humidity, ventilation, energy or equipment constraints. Sound Sleep Study report pages 11 and 16

The required design response is to limit the change heard at the bed, as well as the total sound level, and to control tonal, impulsive and structure-borne components. Equipment location, capacity selection, modulation, air-path sizing, attenuation, isolation and coordinated control sequences are remediation options. Section 11 defines an explicit acceptance requirement. Uncertainty about a single biological threshold does not remove this exposure from the project scope.

Air and temperature belong in the bedroom brief

Strøm-Tejsen and colleagues conducted two small dormitory ventilation interventions. In the main quiet-fan experiment, mean overnight CO2 was approximately 2,395 ppm in the lower-ventilation condition and 835 ppm with increased ventilation. Actigraphic sleep and some next-day measures improved. Ventilation changed multiple contaminants, and actigraphy did not measure sleep stages. The study supports quiet overnight ventilation; it does not isolate CO2 as a cause of N3 loss. Strøm Tejsen et al 2016

Home monitoring of 50 older adults across 10,903 person-nights associated warmer conditions with poorer sleep beyond an observed favorable temperature range, with considerable individual variation. This is evidence for thermal adaptability and heat protection, not a universal bedroom temperature prescription. Age, bedding, clothing and personal circumstances make one rigid setpoint an inadequate human requirement. Baniassadi et al 2023

For design, the bedroom is a combined operating condition: door closed, occupants present, shades deployed, equipment in standby and mechanical systems maintaining the required environment. Outdoor air, return or transfer paths, acoustic privacy, light leakage and thermal control must work together under that condition. Testing an empty bedroom in daytime does not verify it.

Air quality has human performance evidence

Allen and colleagues exposed 24 office workers to controlled indoor conditions across six workdays. Decision-making scores differed substantially among the tested ventilation, VOC and CO2 conditions. The widely repeated percentage improvements describe scores on a particular simulation; they cannot be translated into doubled intelligence or workplace productivity. The study supports treating indoor exposure as relevant to higher-order task performance while recognizing its small sample and short duration. Allen et al 2016

Zhang and colleagues provide an important refinement. Twenty-five participants experienced conditions with added pure CO2 or accumulated human bioeffluents at different ventilation rates. Pure CO2 at the tested concentrations did not significantly worsen the measured symptoms or cognition. At the bioeffluent condition corresponding to 3,000 ppm CO2, headache, fatigue, sleepiness and difficulty thinking clearly increased, with changes in several tasks. This is a direct controlled-human line connecting an indoor environmental condition to symptoms people recognize. It also shows why the gas displayed on a dashboard should not be assumed to be the only causal agent. Zhang et al 2017

Real-world evidence extends the question beyond a laboratory. A yearlong study of 302 office workers in 42 buildings across six countries associated higher indoor PM2.5 and CO2 with slower or poorer performance on selected mobile cognitive tests. It was observational, and CO2 served as a ventilation proxy; correlated exposures and residual confounding remain. The design implication is to consider particle control and ventilation together, rather than assuming either is a complete substitute for the other. Cedeño Laurent et al 2021

ASHRAE’s current CO2 position cautions that interpretation depends on occupancy, generation, outdoor concentration, distribution and measurement. CO2 cannot describe all indoor air quality, and evidence for direct cognitive effects remains unsettled. A low reading does not verify removal of cooking particles, material emissions or other non-occupant sources. A universal 1,000 ppm toxicity threshold is not an appropriate foundation for this paper. ASHRAE carbon dioxide position 2025

Thermal and ventilation conditions can change school task performance

Wargocki and Wyon’s classroom interventions changed temperature and outdoor-air supply. Lower temperature and greater ventilation improved performance on several numerical or language exercises under the tested conditions. Task speed is not the same as long-term learning, and a few classrooms do not define a universal temperature requirement. The useful conclusion is that actual occupancy, heat gains and delivered ventilation can influence the conditions for schoolwork. Wargocki and Wyon 2007

In a prospective study of 162 elementary classrooms, higher estimated ventilation was associated with lower illness-related absence. This was an observational relationship, not a guaranteed infection-prevention percentage. It reinforces the importance of operational delivery and maintenance after design. Mendell et al 2013

Sunyer and colleagues followed 2,715 children in Barcelona schools. Higher traffic-related pollution was associated with slower development of selected cognitive measures. The exposure included elemental carbon, nitrogen dioxide and ultrafine particles, rather than PM2.5 alone. Confounding cannot be eliminated. Site assessment and outdoor-air intake strategy are reasonable responses; promising that a filter will recover a specific developmental deficit is not. Sunyer et al 2015

Light can support alertness but brightness has tradeoffs

A laboratory study of 32 adults found improved subjective alertness and some vigilance measures under a brighter eye-level lighting condition during working hours. Effects depended on timing and task. The result supports considering daytime exposure, while avoiding a universal claim that more light improves all work. Glare, reflections and individual control remain part of the same design problem. Smolders et al 2012

Two office studies connect daylight conditions with sleep and function, with different evidential strength. A 49-person observational pilot found better sleep in workers with windows, but selection and other differences could contribute. A later 30-worker crossover study compared an optimized daylight-and-view condition with an office with blinds and reported sleep and simulation-score benefits. That intervention combined several changes, lasted a short period and included manufacturer involvement. Neither study supports a fixed productivity return from glazing. Both show why façade and shading decisions deserve early coordination with occupied positions. Boubekri et al 2014 Boubekri et al 2020

Distraction has acoustic and interface sources

Unwanted intelligible speech can interfere with concentrated work. Hongisto’s model synthesized task-performance literature using speech intelligibility, illustrating why sound level alone cannot describe distraction. Its wide range of published task effects is not a project productivity forecast. The design response depends on whether speech is desired within a group or intrusive across groups. Hongisto 2005

Technology can also impose attention costs directly. Stothart and colleagues found that receiving phone notifications disrupted performance on an attention task even without participants using the device. Applying this to building alerts is a design inference: define urgency, destination, quiet modes and escalation, and avoid sending every operational event to every occupant. It is not evidence for a specific recovery time after each building notification. Stothart et al 2015

A useful project objective is to reduce avoidable environmental interference with the task. This can be evaluated through physical conditions, interruption counts and occupant feedback. It should not be converted into an unsupported “cognition score” for a room.

Speech understanding and listening effort are separate outcomes

In an experiment with 18 young adults with normal hearing, Picou and colleagues found that noise and reverberation both impaired word recognition. Noise increased measured listening effort; reverberation did not increase that particular effort measure. The distinction matters: it supports controlling background noise and room response without assuming every acoustic variable affects every outcome identically. A brief should also consider older listeners, hearing differences and language needs rather than relying solely on young normal-hearing performance. Picou et al 2016

Desired conversation requires suitable speech-to-noise conditions at the intended listener. Confidentiality requires limiting intelligibility at unintended listeners. These goals can oppose each other. Room boundaries, seating distance, ceiling height, absorption, openings, equipment noise and reinforcement must therefore follow the activity, rather than one universal target for maximum quiet or minimum reverberation.

The Particle library contains a primary four-office intervention paper by Keränen and colleagues. It documents changes in speech propagation after acoustic modifications that reverberation time alone did not adequately capture. This is valuable engineering evidence for measuring the right acoustic property. It is not a human-health trial. It supports selecting criteria that distinguish within-group communication from cross-room distraction and privacy. Keränen et al 2008

Learning evidence strengthens the case for exposure planning

The RANCH study examined 2,844 children near European airports. Aircraft noise was associated with poorer reading comprehension and recognition memory, while sustained attention and overall mental health did not show the same adverse pattern. A generic claim that noise harms every cognitive faculty is not supported. Stansfeld et al 2005

A prospective study around Munich airport relocation followed 326 children. Selected reading and memory outcomes worsened after new noise exposure and improved after former exposure ended. This provides stronger temporal evidence than a single cross-sectional comparison, although the relocation was not randomized. It supports prevention of unwanted exposure without promising an equivalent academic improvement from a residential intervention. Hygge et al 2002

WHO environmental noise guidance uses source-specific, long-term exposure metrics. Those values cannot be substituted directly for indoor equipment criteria, event maxima or partition ratings. An acoustic requirement must identify the receiver, metric, averaging period, operating state and measurement method. WHO environmental noise guidance 2018

Mood and interaction matter even when work continues

A simulated office study found worse mood and physiological stress indicators under open-plan noise, while immediate cognitive performance did not decline. Maintaining output does not establish that an environment is comfortable or cost-free to the person working in it. The bounded design implication is to offer conditions suitable for focused work and relief from intrusive sound. Sander et al 2021

Shared experience also has direct behavioral evidence. In a restaurant experiment involving more than 300 participants, phone availability increased distraction and reduced reported enjoyment of time with friends or family. This was a smartphone study, not a building-controls trial. A reasonable application is to make essential room functions available through convenient local controls so that lighting, shades or sound do not repeatedly require entering a phone interface. Stronger family relationships or greater guest loyalty remain outcomes to investigate rather than established consequences. Dwyer et al 2018

For gatherings, the specification can address speech audibility, privacy, noise buildup and ease of operation. These conditions are tangible and testable. The broader experience remains influenced by the people and occasion as well as the room.

Source control and ventilation address different problems

Air quality should begin with a source inventory: outdoor pollution, combustion, cooking, occupants, furnishings, cleaning products, moisture and any process specific to the space. EPA design guidance emphasizes source selection, low-emission materials and construction sequencing. These decisions precede the final sensor package. A material’s appearance or a generic sustainability label does not by itself specify its emissions in the assembled room. EPA pollutant source design guidance

Particle filtration, outdoor-air ventilation and gas removal have different functions. EPA guidance distinguishes particle clean-air delivery from gaseous contaminant treatment and notes that suitable media and system capacity matter. A filter that is effective at a fan speed occupants will not tolerate acoustically may deliver less useful protection in practice. Reserve pressure capacity, filter space and service access, and evaluate air cleaning at the intended operating point. EPA air cleaner guidance

Intervention evidence includes physiological endpoints. In a randomized crossover trial of 40 older Detroit residents, short periods of portable filtration reduced particulate exposure and systolic blood pressure relative to sham operation. This does not establish prevention of cardiovascular events or the same benefit in homes with lower starting exposures. It demonstrates that reducing an indoor exposure can have a measurable biological effect in a studied population. Morishita et al 2018

Clinical effects are not automatic. A randomized school trial involving children with asthma did not find a significant reduction in primary asthma symptom-days from classroom HEPA purifiers or the tested pest-management intervention. Exposure outside the room, baseline conditions and multiple triggers matter. This finding strengthens the distinction between verified exposure reduction and a guaranteed health outcome. Phipatanakul et al 2021

Dampness and moisture are health design issues

WHO identifies associations between damp or mouldy buildings and respiratory symptoms, allergies and asthma. Preventing persistent moisture and microbial growth is central. The evidence does not establish one airborne mould count that guarantees safety or identify every nonspecific neurological symptom as mould illness. WHO dampness guidance 2009

Moisture control crosses envelope, mechanical and plumbing design. Rain entry, wet construction materials, drainage, condensation, latent loads and leaks require coordinated prevention and access for correction. EPA’s design guidance includes these upstream controls. A room humidity sensor may reveal part of a problem, but cannot substitute for a sound enclosure, drainage or dry construction. EPA moisture control design guidance

Dryness and humidity require balance

A yearlong office study associated humidity with selected reports of throat or skin dryness and unusual fatigue, with differences between subgroups. The findings were observational and self-reported. They support evaluating persistent dryness alongside symptoms, without proving that one relative-humidity band optimizes every person’s biology. Jones et al 2022

An often-cited influenza experiment found impaired airway defenses and worse illness under low humidity in mice. This provides biological plausibility, not evidence that installing humidification prevents influenza in occupants. Any project humidity strategy must also account for envelope condensation, hygiene, climate, maintenance and occupant needs. Higher humidity is not an unrestricted good. Kudo et al 2019

Combustion radon and water have distinct risk pathways

Carbon monoxide exposure can cause headache, weakness and confusion and can be fatal. This is an established pollutant-specific hazard, not simply a low wellness score. Appliance and exhaust decisions, combustion safety and independent required alarms belong to the appropriate engineering and life-safety scope. A general air-quality dashboard cannot replace that protection. CDC carbon monoxide guidance 2026

Radon addresses a different time horizon: long-term lung-cancer risk rather than immediate fatigue or brain fog. EPA describes measures that can be incorporated during construction, followed by testing. Ground-contact details and a future mitigation path are easier to plan before finishes and service routes are fixed. EPA radon construction guidance 2026

Plumbing also influences exposure through water age, temperature conditions, stagnation and maintenance. CDC’s potable-water guidance addresses Legionella control through system design and a water-management approach. Project engineers should coordinate dead-leg avoidance, insulation, access, appropriate mixing and operational requirements with scald prevention and applicable code. A generic whole-house filter is not proof of microbiological safety. CDC water system guidance 2025

These protections belong in the vision because occupants depend on them even when they cannot perceive the hazard. Their justification does not require an immediate performance or mood benefit.

Mood evidence must distinguish experience from diagnosis

Large observational studies associate light patterns and air pollution with mental-health outcomes. A study of more than 85,000 UK Biobank participants associated greater nighttime light with several psychiatric conditions and greater daytime light with lower prevalence of some conditions. A separate longitudinal cohort associated ambient pollutant mixtures with incident depression and anxiety. Neither establishes that changing a room treats or prevents a psychiatric disorder. They strengthen the rationale for studying exposure over time while leaving clinical causation and intervention benefit unresolved. Burns et al 2023 Yang et al 2023

For a building brief, transient annoyance, perceived stress, satisfaction and comfort are more directly assessable experience outcomes. They should remain separate from diagnoses and from physiological measures such as heart rate or hormone concentrations. No single reading represents the whole emotional experience of a space.

Sleep connects to wider biological and social functions

Experimental sleep-deprivation research shows increased pain sensitivity, while a viral-challenge study associated shorter prior sleep with greater susceptibility to a common cold. A further experiment linked sleep loss to social withdrawal and loneliness-related measures. These findings explain why protecting sleep can matter beyond feeling rested. They do not demonstrate that architectural changes treat pain, prevent infections or repair relationships. The environmental intervention must first show that it improves the relevant exposure, and any downstream outcome requires its own evaluation. Krause et al 2019 Prather et al 2015 Ben Simon and Walker 2018

Healthcare translation requires particular care. A tailored-lighting trial in older adults with dementia reported improvements in sleep questionnaires, depression and agitation measures. Another nursing-home trial improved proxy-rated sleep but not actigraphic sleep. These differences show why caregiver impressions, wearables and physiological sleep measurements should not be merged into one claim. Therapeutic uses require the relevant clinical team; evidence from dementia care is not proof of a treatment effect in healthy residential occupants. Figueiro et al 2019 Hjetland et al 2021

Nature music and scent are optional experience tools

A small randomized crossover study using virtual-reality offices found favorable stress indicators and creativity under biophilic conditions. This is promising short-exposure evidence, not a long-term building trial. Nature views and materials may be reasonable experience choices, while functional air treatment must stand on its own engineering basis. An analysis of reported potted-plant VOC removal found that chamber results do not establish useful air cleaning at ordinary building scale. Yin et al 2019 Cummings and Waring 2020

Music is also context-dependent. In a randomized study of 60 healthy women, music, water sounds and silence before a stressor produced mixed physiological results; music did not uniformly lower stress measures. The implication is to provide choice, appropriate level and an easy off function rather than prescribing a universally calming soundtrack. Thoma et al 2013

Olfactory enrichment is emerging. A small study in older adults reported memory-related benefits from a specific six-month overnight odor protocol. That does not establish benefits from continuously fragrancing a hotel or home. A population survey found self-reported adverse symptoms associated with fragranced products, although it could not establish objective causal incidence. A responsible design approach preserves fragrance-free options and informed user choice. Woo et al 2023 Steinemann 2016

These interventions should be optional layers after the fundamental environmental requirements are met. Their appeal should not allow them to stand in for ventilation, moisture control, glare management or acoustic design.

People need to understand and influence their environment. A study of a university smart building associated perceived control with satisfaction and perceived productivity; its findings were context-specific and partly self-reported. They support taking autonomy seriously without establishing a universal health benefit from any particular interface. Loengbudnark et al 2023

The proposed design requirement is operational: occupants should be able to accomplish common tasks, understand the current state, override an unsuitable automatic action and recover from mistakes. Guest users should not need an account or training to operate basic room functions. Physical reach, approach, dexterity and legibility deserve attention; the US Access Board’s operable-parts guidance provides a useful reference within its applicable scope. It should not be represented as a universal legal requirement for every private residence. US Access Board operable parts guide

Control sequences should distinguish safety, equipment protection, maintenance and occupant convenience. A maintenance alert can be routed to the responsible operator rather than waking a guest. A temporary override needs a clear duration. Loss of connectivity should leave an understandable local operating state. Conflicting shade, light and thermal routines require an agreed priority rather than repeated automatic reversals. Control behavior should also be adjustable after handover, so routines can be tuned as actual occupancy, schedules and preferences become known rather than fixed permanently at commissioning.

Sensors can support these behaviors, but they should collect only what is needed to operate and evaluate the system. The proposed project brief should define data access, retention and who receives notifications. Privacy and security should be designed as requirements in their own right. The research reviewed here does not validate claims that ordinary security cameras necessarily cause chronic neurological harm.

User testing can assess first-use success, unnecessary steps, wrong-mode errors, failed overrides and support calls. These are direct measures of whether technology imposes avoidable effort. A claim about reduced clinical stress would require a different study.

A multi-domain review found heterogeneous evidence on combined environmental effects, and a classroom pilot illustrates the difficulty of relating several changing parameters to performance. There is no validated universal equation that adds an air benefit, a lighting benefit and an acoustic benefit into one percentage improvement in human performance. Torresin et al 2018 Brink et al 2022

Coordination is nevertheless necessary for a simpler engineering reason: one system can compromise another system’s objective. The following conflicts should be resolved in the design brief and coordination process, rather than left to independent equipment selections.

This matrix is a design synthesis, not a set of tested health interventions. It shows why the responsible unit of design is the occupied room and its use, including all systems operating together.

The research establishes reasons to care about exposure. The timing argument follows from how buildings are designed. Orientation and façade openings influence daylight, noise and thermal load. Adjacency determines proximity to plant, lifts, kitchens and gathering areas. Room geometry and material area constrain acoustic response. Shafts, ceiling depth and service zones constrain quiet airflow and filtration. Wet-room placement and access influence leak consequences and maintenance. These decisions set the range of conditions that later equipment can economically deliver.

Software can coordinate equipment within that range. It cannot by itself provide missing duct area, eliminate structural sound transmission, create a soil-gas pathway or change a completed façade. Retrofitting may be possible, but it carries physical and cost consequences. That is why human requirements should drive schematic alternatives before the team is asked to optimize individual devices.

Commissioning practice provides an established process for translating intent into requirements. The GSA Commissioning Guide places Owner’s Project Requirements, roles and verification within a lifecycle process. WBDG describes the Basis of Design as the technical response to those requirements. These are useful process references; they do not impose a universal legal mandate on all private projects. GSA Commissioning Guide 2020 WBDG commissioning documents guide

For this application, the Owner’s Project Requirements should name the intended activities, relevant occupants, desired conditions, operating assumptions, evidence basis, acceptance method and responsibility. The Basis of Design should explain how architecture and each engineering discipline will produce those conditions. Drawings locate the provisions, specifications define performance and submittals, sequences define behavior, and commissioning tests delivery.

Decisions by project stage

The project lead does not need to predict each occupant’s biological response to recognize these as design responsibilities. The defensible obligation is to identify material environmental requirements, resolve their interactions and document what the project will deliver.

The following scope is proposed for adaptation to the project and the responsible licensed professionals. Blend’s coordination role should be defined in the contract, with clear boundaries between analysis, integration, design authority, installation and acceptance.

Architecture interiors envelope and acoustics

Establish activity zoning, daylight opportunity, quiet façades, buffers, room volume, speech distances and privacy boundaries. Coordinate glazing and blackout details, absorptive area, material emissions, cleanability and access. Acoustic analysis should address source, path and receiver, including flanking paths through floors, ceilings, doors, ducts and penetrations. A product rating is not equivalent to field performance of the completed room.

Required outputs should include an activity and occupancy schedule, a preliminary environmental criterion schedule, acoustic and daylight assumptions, critical details and a coordination record of accepted tradeoffs. Modeling tools should report assumptions and sensitivity to material, geometry and equipment changes. Field measurements should test the relevant predictions.

Mechanical

Document outdoor-air delivery for actual occupancy and modes; particle treatment and any justified gas treatment; pressure relationships; thermal zoning; latent-load and humidity strategy; source capture; and maintenance access. Coordinate fan and terminal performance with receiving-room acoustic requirements, including low-load cycling and full-occupancy operation. Carry a separate sleep-space transition requirement covering starts, stops, speed changes, damper and valve movement, pumps and defrost where applicable. Coordinate equipment schedules, attenuation and isolation details, and sequences with that requirement; a steady-state catalog sound rating is insufficient. Define how outdoor pollution, smoke events or equipment faults change operation without implying that ventilation can simply be abandoned.

ASHRAE 62.1 and 62.2 address different building scopes, while Standard 55 provides thermal-comfort methods. The responsible team must select the applicable adopted editions and project methods. These references do not create a universal CO2 health limit or one ideal sleeping temperature. ASHRAE Standards 62 overview ASHRAE Standard 55 overview

The drawings should show critical intake, exhaust, distribution, transfer and access provisions. Specifications should define the performance needed at the actual operating point, and sequences should explain how competing air, thermal and acoustic requirements are handled. Test and balance should be followed by occupied-mode verification.

Electrical and lighting

Provide the circuits, zoning, drivers and control compatibility needed for the agreed day, evening, sleep and task conditions. Require relevant spectral and photometric information, dimming stability and evaluation of temporal light modulation across the used range. Coordinate reflected glare, displays, indicators and emergency requirements with occupied eye positions and views.

Temporal light modulation deserves explicit attention. A double-blind fluorescent-lighting crossover study found substantially fewer headache and eyestrain reports under the tested high-frequency system. A recent LED experiment found differences in phantom-array visibility and annoyance by age and migraine history. These are bounded results, not evidence that all LEDs damage health. A technical review also identifies limits in current metrics for predicting broader physiological effects. Procurement should therefore name the method, waveform or metric, control combination and tested operating points instead of relying on an unexplained “flicker-free” label. Wilkins et al 1989 Miller et al 2024 Miller et al 2022

Color rendering remains useful for appearance and task needs. It is not a substitute for circadian exposure assessment, temporal modulation data or ocular-safety evaluation. The design should not claim that a high CRI value alone establishes a biological benefit.

Plumbing

Coordinate water-system hygiene, scald protection, insulation, leak detection, shutoff strategy, drainage and service access. Locate and isolate pipework and equipment to protect relevant receiving rooms from intrusive events. Define the operational water-management responsibilities appropriate to the building. Avoid generic statements that a filter or sensor makes the water healthy without identifying the contaminant, treatment purpose and verification method.

Technology and controls

Provide a sensor and data schedule tied to decisions the system will actually make. Define placement, accuracy requirements, calibration or replacement, sampling and averaging, communication dependencies and failure indications. Document priority between automatic routines, local overrides and safety functions. Establish which alerts reach occupants, operators or service personnel and what action each requires.

A control narrative should include occupied, unoccupied, evening, overnight, high-occupancy, outdoor-pollution, maintenance and fault conditions as relevant. It should also describe recovery after power or network interruption. Commissioning should test these transitions, not merely demonstrate that each device can be commanded.

Responsibility at the boundaries

Assign one coordinator to maintain the integrated requirement schedule, while each discipline retains responsibility for its technical design. Assign a commissioning party to test the combined result with appropriate independence. A discrepancy needs a named person responsible for investigation and correction. Otherwise the room can fail while each supplier correctly states that its individual product works.

Write requirements that can be accepted or rejected

Every environmental requirement should contain the following fields. A numerical threshold without these fields can be misleading, while a well-defined qualitative user test can still be useful.

Research exposure levels are not automatically specification limits. A study comparing two temperatures or CO2 conditions does not identify an optimal value for every building. Targets require the applicable standards, climate, occupancy, sensitivities, engineering analysis and client priorities.

Required remediation item for mechanical transitions in sleep spaces

Purpose and target. Reduce avoidable sleep disruption from mechanical operation. Treat starts, stops and capacity changes as separate acoustic events. The proposed project acceptance target is no clearly audible mechanical clicks, bangs or rattles and no perceptible equipment-induced vibration at the bed during the agreed witnessed test, together with compliance with numerical steady-state, event-maximum and background-to-event change limits. This qualitative target is an engineering project preference, not a clinical sleep guarantee; the numerical limits make acceptance repeatable.

Before schematic sign-off, the acoustician and mechanical engineer must enter the room-specific numerical limits, metric definitions and tolerances in the environmental criterion schedule. Include the absolute event maximum and the permitted rise above the preceding stable background; specify the background sampling interval, event window and instrument time weighting so unlike measurements are not subtracted. Add frequency-band and tonal criteria where needed. Apply the relevant engineering guidance and site conditions. Do not adopt the roughly 18 dB research observation as an allowable change. An unassigned numerical criterion is an unresolved design item, not permission to omit remediation. ASHRAE provides HVAC background and sound-quality design guidance; transition limits need an explicitly documented project basis. ASHRAE Noise and Vibration Control

Remediation and documentation. Evaluate plant adjacency, equipment sizing and minimum capacity, fan and compressor modulation, duct and transfer-path velocities, silencers, flexible connections and vibration isolation. Define starts, stops and transitions in the controls sequence, including interactions between ventilation, cooling, heating and dehumidification. Record the chosen provisions on mechanical and architectural drawings, equipment specifications and technology sequences. Maintain required ventilation, moisture control and safety functions while meeting the acoustic requirement.

Acceptance test. Measure at each intended pillow position with doors, windows and shades in the agreed sleep configuration. Use a calibrated sound-level instrument suitable for the room noise floor, synchronized with equipment-state logs. Record the stable background, steady operation, event maxima, event-to-background changes and relevant frequency content. Exercise normal starts and stops, minimum-load operation, speed and stage changes, dampers, pumps and applicable defrost modes. Include representative overnight logging to detect repeated or combined events that a short demonstration misses. Identify unrelated exterior events rather than attributing every peak to the equipment. Repeat season-dependent tests when conditions become available.

Responsibility and closure. The acoustician defines and verifies acoustic criteria; the mechanical engineer owns equipment and distribution performance; the controls designer owns the sequence; installers correct installation defects. The project coordinator assigns one responsible lead for each failure. Any exceeded criterion requires a logged corrective action and retest before closure. Seasonal items remain open with a named owner and due date. Increasing masking noise, reducing required airflow or disabling necessary operation does not close the requirement without a documented reassessment of all affected conditions.

Bedroom example

Proposed purpose: reduce avoidable environmental interference with the occupant’s sleep schedule and overnight comfort. The brief identifies habitual sleep and wake times, household variation, bed positions, required nighttime movement and any special needs volunteered by occupants.

The schematic response locates the room relative to exterior noise, plant, plumbing and active rooms; develops glazing and blackout details; and reserves quiet air paths with the door closed. The coordinated package defines daytime and evening light capability, sleep-mode leakage, receiving-room acoustic criteria, ventilation, personal thermal adjustment and fault behavior. Safety functions remain active.

Acceptance combines eye-level light measurements, nighttime sound-event and background measurements, the mechanical-transition acceptance test above, verified air delivery, temperature and humidity trends, and a demonstration of control behavior. Optional occupant sleep feedback is recorded separately from physical compliance. Consumer wearables cannot establish that the project increased N3 sleep.

Study or workroom example

Proposed purpose: support sustained visual and cognitive work with appropriate air, thermal and acoustic conditions. The brief distinguishes focused individual work from calls and collaboration, including expected occupancy and duration.

The schematic response protects the work position from distracting speech, selects an appropriate daylight and glare strategy, and locates thermal and air distribution for the actual occupied zone. The package coordinates task lighting, display reflections, background sound, privacy, ventilation and notification routing. Acceptance includes representative calls, reading and control tasks alongside environmental measurements. Reported distraction and comfort can inform adjustment without being presented as an intelligence test.

Gathering or hospitality room example

Proposed purpose: support intended conversation and media use under realistic occupancy, with understandable operation for guests. The brief identifies group size, simultaneous activities, privacy expectations and the desired relationship between conversation and reproduced sound.

The schematic response considers seating distance, room volume, absorptive area, service noise and adjacency. Mechanical capacity must accommodate peaks without creating an unacceptable noise or draft condition. Technology should provide obvious local functions and appropriate presets without forcing repeated phone use. Acceptance should include a representative occupied-use trial and speech evaluation, with adjustments to the actual room rather than equipment demonstrations alone.

These are proposed briefs, not descriptions of completed Blend projects. They show how a human objective becomes a coordinated design and acceptance process.

Measure exposures before claiming outcomes

Low-cost air monitors measure selected parameters with varying limitations. EPA guidance does not support interpreting one dashboard value as comprehensive safety. Its sensor guide emphasizes planning, performance evaluation and data interpretation. A project should specify why a sensor is present, what decisions its data can support and what uncertainty remains. EPA indoor monitor guidance EPA Air Sensor Guidebook

CO2, particles, temperature and humidity are different measurements. A generic TVOC trend does not identify every compound or establish compliance with every exposure limit. Environmental sensors do not diagnose inflammation, migraine, cognitive impairment or immune function. Measurements should be linked to the relevant source, occupancy and operating condition, with fault or stale-data states clearly distinguishable from acceptable conditions.

An effective verification sequence begins with design review and equipment submittals, continues through installation and test-and-balance, and then tests the combined room in its intended modes. Early checks should address items that become concealed, including seals, isolation, water management and service access. Handover should include clear operating instructions and responsibility for consumables and maintenance.

Keep three result categories separate

For post-occupancy learning, collect a baseline where possible, record operational changes, compare similar occupancy and seasonal conditions, and seek consent for personal information. Link complaints to time and operating state so that investigations can identify a plausible source. Preserve negative and mixed findings rather than selecting only favorable responses.

Where a credible evaluation is feasible, staged interventions or comparisons can help separate effects. Changing light, ventilation, acoustics and controls simultaneously may be appropriate for the project, but it makes attribution to one component difficult. Comfort and performance can also vary for reasons outside the building. Project reporting should make these limits explicit.

The strongest immediate promise is therefore a documented environmental result. Over time, well-designed evaluations can establish whether that result also improves the experiences and functions important to occupants.

None of this project-level measurement is used to set or revise the targets in this paper; those remain anchored to the published evidence in sections 2 through 8. Where a project generates data worth sharing, Blend’s role is to make it available to outside researchers, not to treat it as its own validation.

What the evidence supports now

The first priority is a human activity brief before schematic options are fixed. The team should identify sleep, work, conversation, privacy, recovery or other uses in concrete terms, then select the environmental requirements relevant to each. The second priority is coordination of source control, geometry, service capacity and control behavior. The third is acceptance testing under realistic operating conditions, followed by maintenance and seasonal learning.

Foundational provisions deserve priority over speculative enhancements: moisture prevention, pollutant source control, appropriate ventilation and filtration, thermal adaptability, light timing and visual comfort, activity-specific acoustics, and usable controls. Optional sensory features can then be evaluated for the intended users rather than presented as universal biological treatments.

For Blend’s scope, Particle’s geometry, wall-material reverberation-time estimate, subwoofer placement and reflection-point outputs are verified against field measurement, as described in section 1, and are treated as validated starting points rather than anecdote; sensors can reveal conditions and operating failures, and integration can coordinate modes and reduce unnecessary interaction. The proposed service should make these contributions traceable to the requirement schedule. This paper does not independently validate Aperture’s outcomes or certification-based health claims; those require their own technical or outcome evidence, and Blend’s own project experience beyond Particle’s verified scope is not treated as evidence anywhere in this paper.

Coverage check from impact to build requirement

Each relevant exposure must have a traceable entry connecting the human concern to a design target, responsible discipline, drawing or specification, acceptance test and corrective action. The following check carries the exposure families reviewed in this paper into delivery. These are project requirements to develop and verify; they do not imply that all symptoms have building-related causes or that every intervention has equal evidence. Record justified exclusions and unresolved criteria explicitly before schematic sign-off, and reconcile the register again before construction documents and handover.

This register also needs a coordination check: an acoustic correction must preserve ventilation and humidity control; a lighting correction must preserve safe movement; an air-cleaning improvement must remain usable at its required operating speed. A row is complete only when the project has a deliverable and a verification route, or a documented reason it does not apply. Evidence uncertainty remains visible alongside the requirement rather than causing the exposure to disappear from scope.

Questions that should remain open

Direct cognitive effects of typical indoor CO2 remain contested. Optimal combined exposure targets for different ages, schedules and sensitivities are incomplete. Evidence does not establish an additive human-performance score across systems. Lighting interventions can improve subjective outcomes without equivalent objective sleep changes. Sound masking, music, scent and biophilic features have context-specific effects. Long-term clinical and financial returns from a complete integrated residential package have not been established by the sources reviewed here.

These gaps limit outcome promises, but they do not prevent responsible design. A project can reduce established hazards and avoidable burdens, preserve occupant choice and verify the conditions it controls. The research supports placing those objectives in the vision and carrying them through schematics, MEPT drawings, specifications and commissioning.

This is a targeted narrative evidence review completed on 5 September 2026 Pacific time, corresponding to 6 September UTC. It combines Blend’s SharePoint research with primary human studies, relevant evidence syntheses and official engineering or public-health guidance. It is not a registered systematic review, meta-analysis, jurisdiction-specific code review or clinical practice guideline.

The internal collection was searched through SharePoint because some locally synchronized files were not available for direct reading. Relevant files in the central Research folder, Blend Building Intelligence research and Particle scientific documentation were reviewed. The index below identifies the material actually consulted; it is not a claim that the entire SharePoint library was read.

Internal research supplied questions and references. Original publications and authoritative guidance were used to support consequential claims. Focused follow-up examined null findings and overextensions, including direct CO2 causality, sleep-stage language, humidity mechanisms, temporal lighting effects, privacy and surveillance claims, scent, and healthcare return on investment. The main exposure families were reviewed with supporting evidence and explicit limitations. A subsequent focused review added mechanical sound transitions and a coverage register to strengthen the connection between research findings and enforceable project requirements. This review does not establish that every potentially relevant exposure has been identified.

Access varied among full papers, institutional manuscripts, official guidance and primary abstracts. Some publisher full texts were restricted or returned access challenges. Where only an abstract or summary was reliably available, this paper stays within the reported findings and cannot assess every method, analysis or disclosure. The olfactory-enrichment and combined-environment discussion is particularly limited in this respect. Manufacturer involvement in the optimized daylight study is noted where used. No study percentages are added together or presented as a forecast for a Blend project.

Scientific and technical sources

Stanchina ML and colleagues. (2005). The influence of white noise on sleep in subjects exposed to ICU noise. Sleep Medicine 6 423-428. Small polysomnographic experiment; background-to-peak change findings were checked against the primary abstract.

Solet JM and colleagues. Evidence Based Design Meets Evidence Based Medicine The Sound Sleep Study. Research report. Printed page 11 documents HVAC isolation and continuous-operation recommendations; page 16 reports REM arousal curves.

ASHRAE. (2023). Chapter 49 Noise and Vibration Control. HVAC Applications Handbook. Engineering background-noise and sound-quality guidance, not a universal sleep-stage threshold.

The links in the paper open the supporting source. The following records provide publication details and concise descriptions of their role. Source types distinguish experimental findings, associations, mechanisms and guidance.

Allen JG MacNaughton P Satish U Santanam S Vallarino J and Spengler JD. (2016). Associations of Cognitive Function Scores with Carbon Dioxide Ventilation and Volatile Organic Compound Exposures in Office Workers A Controlled Exposure Study of Green and Conventional Office Environments. Environmental Health Perspectives 124 805-812. Controlled office exposure study.

ASHRAE. (2023 edition overview accessed September 2026). Thermal Environmental Conditions for Human Occupancy. Official Standard 55 overview. Standard scope and methods.

ASHRAE. (2025 June 25). Human Health and Wellness in the Built Environment. Position document. Professional guidance.

ASHRAE. (2025 editions overview accessed September 2026). Standards 62 1 and 62 2. Official ventilation standards overview. Standard scopes and edition information.

ASHRAE. (2025 revision). Position Document on Indoor Carbon Dioxide. ASHRAE. Professional guidance and evidence appraisal.

Baniassadi A Manor B Yu W Travison T and Lipsitz L. (2023). Nighttime ambient temperature and sleep in community dwelling older adults. Science of the Total Environment 899 165623. Observational home monitoring.

Basner M and McGuire S. (2018). WHO Environmental Noise Guidelines for the European Region A Systematic Review on Environmental Noise and Effects on Sleep. IJERPH 15 519. Systematic review and physiological data reanalysis.

Basner M Müller U and Elmenhorst EM. (2011). Single and Combined Effects of Air Road and Rail Traffic Noise on Sleep and Recuperation. Sleep 34 11-23. Controlled polysomnographic study.

Basner M Smith MG Cordoza M et al. (2026 February 2). Efficacy of pink noise and earplugs for mitigating the effects of intermittent environmental noise exposure on sleep. Sleep zsag001 DOI 10.1093/sleep/zsag001. Controlled polysomnographic experiment.

Ben Simon E and Walker MP. (2018). Sleep loss causes social withdrawal and loneliness. Nature Communications 9 3146. Laboratory sleep deprivation and social response studies.

Boubekri M et al. (2014). Impact of Windows and Daylight Exposure on Overall Health and Sleep Quality of Office Workers A Case Control Pilot Study. Journal of Clinical Sleep Medicine 10 603-611. Observational pilot.

Boubekri M Lee J MacNaughton P et al. (2020). The Impact of Optimized Daylight and Views on the Sleep Duration and Cognitive Performance of Office Workers. IJERPH 17 3219. Short crossover field intervention with manufacturer involvement.

Brink HW et al. (2022). A systematic approach to quantify the influence of indoor environmental parameters on students perceptions responses and short term academic performance. Indoor Air 32 e13116. Pilot classroom assessment.

Brown TM et al. (2022). Recommendations for daytime, evening, and nighttime indoor light exposure to best support physiology, sleep, and wakefulness in healthy adults. PLOS Biology 20 e3001571. Expert consensus informed by human experiments.

Burns AC et al. (2023). Day and night light exposure are associated with psychiatric disorders an objective light study in more than 85000 people. Nature Mental Health 1 853-862. Cross sectional cohort analysis.

Buxton OM et al. (2012). Sleep disruption due to hospital noises a prospective evaluation. Annals of Internal Medicine 157 170-179. Laboratory polysomnographic experiment.

Cedeño Laurent JG et al. (2021). Associations between Acute Exposures to PM2.5 and Carbon Dioxide Indoors and Cognitive Function in Office Workers A Multicountry Longitudinal Prospective Observational Study. Environmental Research Letters 16 094047. Longitudinal observational study.

Chang AM Aeschbach D Duffy JF and Czeisler CA. (2015). Evening use of light-emitting eReaders negatively affects sleep, circadian timing, and next-morning alertness. PNAS 112 1232-1237. Randomized crossover experiment.

Cummings BE and Waring MS. (2020 online 2019). Potted plants do not improve indoor air quality A review and analysis of reported VOC removal efficiencies. Journal of Exposure Science and Environmental Epidemiology 30 253-261. Quantitative reanalysis of chamber findings.

Dwyer RJ Kushlev K and Dunn EW. (2018). Smartphone use undermines enjoyment of face to face social interactions. Journal of Experimental Social Psychology 78 233-239. Restaurant field experiment and experience sampling.

Figueiro MG Plitnick BA Roohan C Sahin L Kalsher M and Rea MS. (2019). Effects of a Tailored Lighting Intervention on Sleep Quality Rest Activity Mood and Behavior in Older Adults With Alzheimer Disease and Related Dementias A Randomized Clinical Trial. Journal of Clinical Sleep Medicine 15 1757-1767. Clinical crossover trial.

Hjetland GJ et al. (2021). Ambient bright light treatment improved proxy rated sleep but not sleep measured by actigraphy in nursing home patients with dementia a placebo controlled randomised trial. Primary journal record on PubMed. Cluster randomized trial.

Hongisto V. (2005). A model predicting the effect of speech of varying intelligibility on work performance. Indoor Air 15 458-468. Model based on prior task studies.

Hygge S Evans GW and Bullinger M. (2002). A Prospective Study of Some Effects of Aircraft Noise on Cognitive Performance in Schoolchildren. Psychological Science 13 469-474. Natural experiment around airport relocation.

International Commission on Illumination. (2024). CIE Position Statement on Integrative Lighting Recommending Proper Light at the Proper Time. CIE PS 001 2024 third edition. Professional guidance.

Jones ER Cedeño Laurent JG Young AS Coull BA Spengler JD and Allen JG. (2022). Indoor humidity levels and associations with reported symptoms in office buildings. Indoor Air 32 e12961. Observational office study.

Keränen JS Virjonen P and Hongisto VO. (2008). Characterization of acoustics in open offices four case studies. Acoustics 08 Paris conference paper in Particle scientific library. Measured physical interventions not a human health trial.

Krause AJ et al. (2019). The Pain of Sleep Loss A Brain Characterization in Humans. Journal of Neuroscience 39 2291-2300. Sleep deprivation experiment and daily observations.

Kudo E Song E Yockey LJ et al. (2019). Low ambient humidity impairs barrier function and innate resistance against influenza infection. PNAS 116 10905-10910. Animal mechanism experiment.

Loengbudnark W Khalilpour K Bharathy G Voinov A and Thomas L. (2023). Impact of occupant autonomy on satisfaction and building energy efficiency. Energy and Built Environment 4 377-385. Building survey and contextual field intervention.

Mason IC et al. (2022). Light exposure during sleep impairs cardiometabolic function. PNAS 119 e2113290119. Randomized laboratory experiment.

Mendell MJ et al. (2013). Association of classroom ventilation with reduced illness absence a prospective study in California elementary schools. Indoor Air DOI 10.1111/ina.12042. Prospective observational study.

Miller NJ et al. (2022). Flicker A review of temporal light modulation stimulus responses and measures. Lighting Research and Technology technical paper hosted by US Department of Energy. Technical research synthesis.

Miller et al. (2024). Visibility and annoyance of the phantom array effect varies with age and history of migraine. Lighting Research and Technology DOI 10.1177/14771535241288783. Laboratory LED waveform experiment.

Morishita M et al. (2018). Effect of Portable Air Filtration Systems on Personal Exposure to Fine Particulate Matter and Blood Pressure Among Residents in a Low Income Senior Facility A Randomized Clinical Trial. JAMA Internal Medicine 178 1350-1357. Randomized double blind crossover trial.

Phillips AJK et al. (2019). High sensitivity and interindividual variability in the response of the human circadian system to evening light. PNAS 116 12019-12024. Controlled human experiment.

Phipatanakul W et al. (2021). Effect of School Integrated Pest Management or Classroom Air Filter Purifiers on Asthma Symptoms in Students With Active Asthma A Randomized Clinical Trial. JAMA 326 839-850. Randomized trial with null primary clinical result.

Picou EM Gordon J and Ricketts TA. (2016). The Effects of Noise and Reverberation on Listening Effort in Adults With Normal Hearing. Ear and Hearing 37 1-13. Laboratory listening experiment.

Prather AA et al. (2015). Behaviorally Assessed Sleep and Susceptibility to the Common Cold. Sleep 38 1353-1359. Observed sleep preceding experimental viral challenge.

Sander EJ Marques C Birt J Stead M and Baumann O. (2021). Open plan office noise is stressful multimodal stress detection in a simulated work environment. Journal of Management and Organization 27 1021-1037. Short experimental office simulation.

Schmidt FP et al. (2013). Effect of nighttime aircraft noise exposure on endothelial function and stress hormone release in healthy adults. European Heart Journal 34 3508-3514. Randomized home exposure experiment.

Smolders KCHJ de Kort YAW and Cluitmans PJM. (2012). A higher illuminance induces alertness even during office hours findings on subjective measures task performance and heart rate measures. Physiology and Behavior 107 7-16. Laboratory experiment.

Stansfeld SA et al RANCH study team. (2005). Aircraft and road traffic noise and children’s cognition and health a cross national study. Lancet 365 1942-1949. Cross sectional school study.

Steinemann A. (2016). Fragranced consumer products exposures and effects from emissions. Air Quality Atmosphere and Health 9 861-866. Self reported population survey.

Stothart C Mitchum A and Yehnert C. (2015). The Attentional Cost of Receiving a Cell Phone Notification. Journal of Experimental Psychology Human Perception and Performance 41 893-897. Controlled attention task experiment.

Strøm Tejsen P Zukowska D Wargocki P and Wyon DP. (2016). The effects of bedroom air quality on sleep and next day performance. Indoor Air 26 679-686. Two small field ventilation interventions.

Sunyer J et al. (2015). Association between Traffic Related Air Pollution in Schools and Cognitive Development in Primary School Children A Prospective Cohort Study. PLOS Medicine 12 e1001792. Prospective child cohort.

Thoma MV et al. (2013). The effect of music on the human stress response. PLOS ONE 8 e70156. Randomized laboratory stress experiment.

Torresin S et al. (2018). Combined effects of environmental factors on human perception and objective performance A review of experimental laboratory works. Indoor Air 28 525-538. Review abstract limited assessment.

US Access Board. (Accessed September 2026). Chapter 3 Operable Parts. Guide to the Architectural Barriers Act Accessibility Standards. Accessibility guidance within applicable scope.

US Centers for Disease Control and Prevention. (2025 January 3). Controlling Legionella in Potable Water Systems. CDC. Water management guidance.

US Centers for Disease Control and Prevention. (2026 January 12). Carbon Monoxide Poisoning Basics. CDC. Public health and safety guidance.

US Environmental Protection Agency. (2018 second edition and current webpage). Guide to Air Cleaners in the Home. EPA. Residential engineering and health guidance.

US Environmental Protection Agency. (2022 guide webpage updated April 20 2026). How to Use Air Sensors Air Sensor Guidebook. EPA. Planning evaluation and data quality guidance.

US Environmental Protection Agency. (2026 August 17 update). How to Address Radon When Building a New Home. EPA. Construction and testing guidance.

US Environmental Protection Agency. (Accessed September 2026). Controlling Pollutants and Sources Indoor Air Quality Design Tools for Schools. EPA. Source control design guidance.

US Environmental Protection Agency. (Accessed September 2026). Low Cost Air Pollution Monitors and Indoor Air Quality. EPA. Measurement limits and interpretation.

US Environmental Protection Agency. (Accessed September 2026). Moisture Control Part of Indoor Air Quality Design Tools for Schools. EPA. Envelope construction and condensation guidance.

US General Services Administration. (2020 September). GSA Commissioning Guide. GSA guide hosted by WBDG. Lifecycle commissioning process.

Wargocki P and Wyon DP. (2007). The Effects of Moderately Raised Classroom Temperatures and Classroom Ventilation Rate on the Performance of Schoolwork by Children RP 1257. HVAC and R Research 13 193-220. Classroom field interventions.

Whole Building Design Guide. (Accessed September 2026). Commissioning Documents Process Contents and Acceptance. WBDG. Owner requirements and technical design process.

Wilkins AJ Nimmo Smith I Slater AI and Bedocs L. (1989). Fluorescent lighting headaches and eyestrain. Lighting Research and Technology 21 11-18. Double blind crossover field intervention.

Woo CC et al. (2023). Overnight olfactory enrichment using an odorant diffuser improves memory and modifies the uncinate fasciculus in older adults. Frontiers in Neuroscience. Small intervention abstract limited review.

World Health Organization Regional Office for Europe. (2009). WHO guidelines for indoor air quality dampness and mould. WHO. Evidence based public health guidance.

World Health Organization Regional Office for Europe. (2018). Environmental Noise Guidelines for the European Region. WHO. Population exposure guidance.

Yang T Wang J Huang J Kelly FJ and Li G. (2023). Long term Exposure to Multiple Ambient Air Pollutants and Association With Incident Depression and Anxiety. JAMA Psychiatry 80 305-313. Prospective cohort analysis.

Yin J et al. (2019). Effects of biophilic interventions in office on stress reaction and cognitive function A randomized crossover study in virtual reality. Indoor Air 29 1028-1039. Small virtual reality crossover experiment.

Zhang X Wargocki P Lian Z and Thyregod C. (2017). Effects of Exposure to Carbon Dioxide and Bioeffluents on Perceived Air Quality Self assessed Acute Health Symptoms and Cognitive Performance. Indoor Air 27 47-64. Controlled repeated exposure study.

Internal research consulted

These documents were used as research leads and context. They are not independent confirmation of the studies they summarize. The primary acoustic conference paper is identified separately.

Air Quality Metrics for Biological Resilience (Primary Research).docx. Internal research synthesis or research working document used to identify and audit claims.

Air Quality Research .docx. Internal research synthesis or research working document used to identify and audit claims.

Artificial Light's Impact on Humans.docx. Internal research synthesis or research working document used to identify and audit claims.

Characterization_of_acoustics_in_open_offices_-_four_case_studies.pdf. Primary conference paper from Particle Scientific Documentation; also cited in the scientific sources.

Children, Indoor Environmental Quality, and Educational Performance.docx. Internal research synthesis or research working document used to identify and audit claims.

Executive Summary2.pdf. Internal research synthesis or research working document used to identify and audit claims.

Expand Air Quality framework.docx. Internal research synthesis or research working document used to identify and audit claims.

Flicker and CRI_ Human Health Impacts.docx. Internal research synthesis or research working document used to identify and audit claims.

Invisible flicker from LED drivers causes headaches.docx. Internal research synthesis or research working document used to identify and audit claims.

LUX journal.pbio.3001571.pdf. Stored copy of Brown et al 2022; the public original is cited above.

MT_SWF_WayfindingDesign.pdf. Practitioner wayfinding reference used for context, not proof of a physiological effect.

Scent, Biophilia, and Indoor Air Quality (1).docx. Internal research synthesis or research working document used to identify and audit claims.

Security Technology's Human Impact Research.pdf. Internal research synthesis or research working document used to identify and audit claims.

The Clinical and Financial Imperative of Blended Environmental Design in Modern Healthcare.docx. Internal research synthesis or research working document used to identify and audit claims.

Claims from the internal collection that were not adopted

The paper does not carry forward claims that high color rendering alone protects long-term ocular or cardiovascular health; that every LED system causes neurological damage; that one dimming percentage eliminates health risk; that CO2 alone universally causes deep-sleep loss; or that a single humidity band is a proven biological requirement for every building. It also excludes unsupported claims about radon as an acute brain-fog cause, inevitable surveillance-related neurological harm, automatic gains in biological age, and guaranteed clinical or financial returns from a complete building package.

These exclusions preserve the strongest argument in the collection: environmental conditions are consequential, many are designable, and the project should deliberately specify and verify the ones that matter to its occupants.