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Economics and Justification Appendices

Appendices

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Economics & Justification

Appendices and Additional Resources

Health

  1. Physical Health
    1. General Safety:
      1. Thermal Comfort: Can avoid unnecessary heat and cold stress, provide better focus, maintain better posture, and reduce fatigue.
      2. IAQ: Poor IAQ can reduce occupant comfort and productivity, leading to distraction or even the inability to work effectively. This could lead to situations where employees or residents are less aware of potential hazards, affecting overall safety.  Also, IAQ can cause emergency evacuation, e.g. CO concentration is too high.
      3. Lighting:  Proper lighting improves visibility, allowing individuals to see potential hazards like uneven surfaces, obstacles, or spills, minimizing the risk of falls or slips.  The presence of natural light also associated with injuries. Falls are more likely with inadequate natural lighting in the home. Sufficient lighting ensures that workers can clearly see their surroundings, including potential hazards like machinery, equipment, or moving objects, enabling them to react appropriately and avoid accidents.  Good quality lighting, reduces the chance of incidents and injuries from "momentary blindness" (momentary low field vision due to eyes adjusting from brighter to darker, or vice-versa, surroundings).
      4. Acoustic:  Noise level, if too high, may mask the alert of danger from other colleagues. Unhealthy high level of ambient noises can cause hearing humming noise, or temporary hearing loss.
    2. Respiratory Issues:  Ambient air quality and its deleterious effects on human health have been brought to the forefront in recent times.  Air cleaning, as a comprehensive environmental intervention, decreases exposure to indoor pollutants.  Poor air quality can cause or exacerbate respiratory problems including:
      1. Asthma: Exposure to PM2.5 or NO2 air pollution during early childhood may play a role in the development of childhood asthma, especially in lower income families living in densely populated communities.  Per ASHRAE “Limiting Indoor Mold and Dampness in Buildings” Position Document, “..public health authorities have documented consistent associations between damp buildings and increased risks of adverse health effects, including exacerbation of existing asthma, new asthma, respiratory infections and allergic rhinitis (IOM 2004; WHO 2009). In addition, credible researchers have documented a causal link between damp buildings and exacerbations in children with asthma.”  A meta-analysis showed that children living in a home with damp or mould were 50% more likely to have asthma or wheezing.
      2. Allergies: Indoor air can have a lot of allergens, such as pollen, airborne pollutants produced by dust mites or cockroaches, and mold. These substances irritate the airways of people with allergies.
      3. Bronchitis: Childhood NO2 and PM10 exposures were associated with adult bronchitis symptoms.
      4. Chronic Obstructive Pulmonary Diseases (COPD): Indoor pollutant exposure, including PM 2.5 and NO2, was associated with increased respiratory symptoms and risk of COPD exacerbation, especially in developing nations.
      5. Poisoning: Carbon monoxide can provoke direct poisoning when breathed in at high levels. Heavy metals such as lead, when absorbed into the human body, can lead to direct poisoning or chronic intoxication, depending on exposure.  Per ASHRAE “Unvented Combustion Devices and Indoor Air Quality” Position Document, “...unvented combustion appliances should never be used as the primary/sole source of heating…About 170 people in the United States die every year from carbon monoxide (CO) produced by non-automotive consumer products.
      6. Lung Cancer: PM2.5 has been is linked to the development of lung cancer. Radon gas and smoke from burning domestic fuels further elevate lung cancer risk when exposed over extended periods of time.
    3. Obesity and Type 2 Diabetes:  Mild cold exposure at temperatures between 12 °C and 22 °C and heat exposure at temperatures above 30 °C were regarded as anti-obesity and anti-diabetes treatments.   PM2.5 can also contribute to Type 2 Diabetes.  Mildly cold or warm environments, outside the standard comfort zone, increases metabolism and energy expenditure which may help to tackle obesity.  For those with type 2 diabetes, exposure to mild coldness influences glucose metabolism and after 10 days of intermittent cold, patients had increased insulin sensitivity by more than 40%.  Noise pollution can cause or exacerbate type 2 diabetes
    4. Building-Related Illness:
      1. Poor IEQ can lead to Building-Related Illness (BRI), which includes a cluster of symptoms such as headaches, fatigue, eye irritation, and respiratory discomfort. Improving ventilation and controlling indoor pollutants can significantly reduce these symptoms.  Some health effects may show up shortly after a single exposure or repeated exposures to a pollutant. These include irritation of the eyes, nose, and throat, headaches, dizziness, and fatigue. Such immediate effects are usually short-term and treatable. Sometimes the treatment is simply eliminating the person's exposure to the source of the pollution, if it can be identified.  The largest U.S. study of building characteristics and occupant symptoms is the EPA Building Assessment Survey and Evaluation (BASE) Study of 100 representative office buildings.  Analyses of data from this study indicate a general decrease in BRI symptoms as study space ventilation rates increase from as low as 10 cfm (4.7 L/s) per person up to approximately 25 to 35 cfm (12 to 17 L/s) per person. 20% to 30% fewer occupants reported BRI symptoms in study spaces with ventilation rates above 20 to 25 cfm (9.4 to 11 L/s)  per person, compared to study spaces with lower rates typically ranging between 10 and 20 cfm (4.7 and 9.4 L/s) per person.
      2.  The elements that can impact BRI potentially include:
        • Particulate matter (PM2.5 & PM10)
        • Chemicals
        • Carbon monoxide (CO)
        • Mold and mildew spores
        • Radon (especially in basements)
        • Allergens (pollen, pet dander, dust mites)
        • Lead (Pb)
        • Nitrogen Dioxide (NO2)
        • Ozone (O3)
        • Sulphur Dioxide (SO2)
        • Formaldehyde
        • Asbestos
      3.  Thermal Environment: Thermal environment can impact Building-Related Illness
      4.  Impacts on Lighting, Acoustics, and thermal comfort: Poor and inappropriate lighting with absence of sunlight, bad acoustics, poor ergonomics and humidity may also contribute to BRI. Too bright or flickering lights are elements that may cause BRI
    5. Skin and IEQ:  Exposure to indoor pollutants like VOCs, chemicals, or low humidity can lead to skin irritation, dryness, or rashes. Long-term exposure could increase the risk of dermatological issues.
      1. Premature Skin Aging - UV exposure can cause permanent skin damage. In the last few decades, it has become increasingly clear that air pollution is also at fault for premature skin aging.  Back in 2010, research revealed that an increase in particulate matter (PM) due to traffic-related air pollution was associated with a 20 percent increase in pigment spots on the forehead and cheeks. In less-trafficked areas, researchers found that moderate levels of “background” (non-traffic related) particulate matter was accelerating skin aging in similar ways.  In 2017, a follow up study was done to examine the effects of indoor fine particle pollution  (PM2.5) exposure on skin aging, higher indoor PM2.5 levels (associated with factors such as cooking with solid fuels and inadequate indoor ventilation) were linked to an increase in pigment spots and wrinkles.
      2. Eczema - Eczema, also known as atopic dermatitis (AD), is a chronic skin condition that causes red, itchy patches on the skin that can periodically flare-up in response to environmental triggers. Although the primary risk factor for developing eczema is genetic (i.e. if you have a family history of allergies and skin conditions), research shows that environmental factors like air pollution, humidity, and temperature play a significant role in triggering and aggravating symptoms.   Aside from family history, exposure to specific indoor pollutants such as airborne chemicals (VOCs) and PM2.5 may also increase your risk of developing eczema at a young age, through what's referred to as "gene-environment interactions".  One study of primary school children in Seoul, Korea, found that eczema rates were significantly higher for children who had a family history of allergic diseases and had moved into a newly built house in their first year of life. Because harmful chemicals (VOCs) are emitted by many common building materials, fresh paint, and furniture, new houses tend to have higher levels of indoor chemical pollution. Additionally, newer houses are more airtight (to improve energy efficiency), which can cause air pollution to reach higher concentrations than outdoors. For these reasons, moving to a new home was considered an environmental trigger for the eczema gene.  Even if you live in an older home, you may still be vulnerable to air quality related symptoms. In addition to building materials, routine household activities such as cooking and cleaning can increase airborne pollution levels and trigger eczema flare-ups.
      3. Hives - Hives, also called urticaria, is a spontaneous skin reaction that occurs in response to specific allergens. Most people experience hives at least once in their lifetime, brought on by specific foods, medications, insect bites, sunlight, pet dander, or another (known or unknown) environmental trigger.  For some people, an increase in airborne pollutants like PM2.5, VOCs, ozone (O3), and nitrogen dioxide (NO2) can trigger a hives outbreak. A study conducted in Windsor, Canada, found that emergency room visits for hives increased in relation to short-term spikes in ambient air pollution. Similar to eczema, another study noted an association between chronic cases of hives in children and living in a new residence.
      4. Irritation, Breakouts, and Inflammation - Even if you don’t have an existing skin condition, airborne pollutants can cause everyday skin aggravation. Just as large particles such as dust and dirt collect on our skin, so do fine particles that are invisible to the naked eye. This microscopic build-up of pollution can trigger acne-like breakouts and disturb our skin’s natural flora (the microbiome of bacteria that exist on the outermost layer of our skin).  Many of the bacteria on our skin, such as Staphylococcus epidermidis, act as anti-inflammatories and help defend against potential pathogens. When air pollution upsets the natural balance of this ecosystem, it can decrease our skin’s ability to combat dryness, humidity, sunlight, UV radiation, pathogens, and allergens.
      5. Decrease in Skin Barrier Function: This paper concludes low humidity and low temperatures lead to a general decrease in skin barrier function and increased susceptible towards mechanical stress. Since pro-inflammatory cytokines and cortisol are released by keratinocytes, and the number of dermal mast cells increases, the skin also becomes more reactive towards skin irritants and allergens. Exposure to intense heat, UV radiation, pollution, and smoke can break down the skin’s protective lipid coat, deplete skin antioxidants, and trigger oxidative stress
    6. Increased Risk of Illness:  Poor IEQ can affect the immune system, making individuals more susceptible to infections, colds, and flu. Contaminants like bacteria and viruses may thrive in certain relative humidity (see below), poorly ventilated indoor spaces, and temperatures.
      1. Relative Humidity - The Sterling chart, from a 1986 research paper, suggests an optimum zone of 30 to 60 percent for relative humidity to minimize microbial activities.  ASHRAE Handbooks updated 30 to 60 percent.

      2. Optimal Thermal Comfort Range: Maintaining an appropriate environmental condition reflecting the requirements of the Standard 55.
      3. Indoor Air Quality - In renovations for better energy performance with tighter building envelope, evidence shows that certain retrofits increase the risk of health problems, particularly for airways, skin, and eyes.
      4. Daylighting -   Individuals with household sunlight exposure were 94% less likely to be diagnosed with tuberculosis than those without. An increased risk of leprosy associated with insufficient natural light exposure.
    7. Legionnaires’ Disease: Between 2000 and 2017, the number of Legionnaires’ Disease diagnoses grew by 5.5 times.  Breathing in water droplets that is contaminated can contribute to this disease.
    8. Cardiovascular: Per ASHRAE “Environmental Tobacco Smoke” Position Document:  “based on the preponderance of evidence, that exposure of nonsmokers to tobacco smoke causes specific diseases and other adverse effects to human health most significantly, cardiovascular disease and lung cancer.”  Research by EPA and others has found that exposure to increased concentrations of PM2.5 over a few hours to weeks can trigger cardiovascular disease-related heart attacks and death. Longer-term exposure can lead to increased risk of cardiovascular mortality and decreases in life expectancy.”  Noise pollution can cause or exacerbate cardiovascular disease.
    9. Passive Survivability:  Per DOE, Passive Survivability is “The ability to maintain safe indoor conditions in the event of extended energy outage or loss of energy supply. In practice, passive survivability enables safe indoor thermal conditions, relying on building design measures that require no energy.”  It is important that a building does not exceeds the survival temperatures (hot and cold) during prolonged power outage.  Besides thermal autonomy, daylighting and ventilation autonomy are also important for prolong power outage and survivability.
  2. Mental Health
    1. Stress and Mental Health: Poor IEQ is linked to mental health issues, such as increased stress, and mood disorders. The indoor environment is widely acknowledged as a non-pharmacological tool for regulating residents’ mental health. It is widely accepted that elements of IEQ, such as daylighting, thermal comfort, acoustics, and indoor air quality can significantly influence people's mental health. These elements can either diminish feelings of well-being or convey positive and negative information, impacting individuals' self-esteem, sense of security, and identity. 
      1. Anxiety Disorder:   Accumulating data suggest that air pollution increases the risk of internalizing psychopathology, including anxiety and depressive disorders. In another study, students’ perceptions of dormitory IEQ significantly affected anxiety symptoms, explaining 40% of the variance
      2. Mood Disorder:  Depression, bipolar, etc. mood disorder can be impacted by IEQ.  Indoor air quality, exposure to natural light and adequate lighting can impact the mood of a person.
        The impact of acoustic, or music therapy, can evoke memories in patients, to improve their mood and to alleviate stress. Artificial light at night and depressions:  Nine eligible studies were included in this review.  Overall,moderate evidence of a positive association between light at night exposure and depressive symptoms and to a lesser extent other mental disorders.
        Light Therapy and seasonal affective disorder and other types of depression:  can be effectively reduced by both natural and artificial light therapy. 
        Daylight, happiness, and sadness:  natural lighting conditions of housing significantly impact people's perceptions of happiness and sadness, with settings that have an increased amount of daylight entering the home leading to the greatest impacts.
        Heat stress and its consequences on mental well‐being -  Chronic heat stress can lead to increased stress, anxiety, and cognitive impairment.
        Lighting and view: A seminal study over 20 years ago showed that workers who had window views of nature felt less frustrated and more patient, and reported better health than those who did not have visual access to the outdoors or whose view consisted of built elements only.  Various studies since then have suggested similar conclusions, and although from the healthcare sector.  Another study of workers in a Californian call centre found that having a better view out of a window was consistently associated with better overall performance: workers were found to process calls 7% to 12% faster. Computer programmers with views spent 15% more time on their primary task, while equivalent workers without views spent 15% more time talking on the phone or to one another.
    2. Indoor Air Quality: The link between air pollution and poor mental health may relate to neurostructural (relationship between the nervous system and body structure) and neurofunctional (the relationship between the nervous system (neuro) and its function) changes. the majority of studies (73%) reported higher internalizing symptoms and behaviors with higher air pollution exposure. Air pollution was consistently associated (95% of articles reported significant findings) with neurostructural and neurofunctional effects (e.g., increased inflammation and oxidative stress, changes to neurotransmitters and neuromodulators and their metabolites) within multiple brain regions (24% of articles), or within the hippocampus (66%), PFC (7%), and amygdala (1%). The most studied exposure time frames were adulthood (48% and 59% for literature search) and the prenatal period (26% and 27% for literature). The extant literature suggests that air pollution is associated with increased depressive and anxiety symptoms and behaviors, and alterations in brain regions implicated in risk of psychopathology.  Fire smoke may also contributes to memory loss in Alzheimer diseases.
    3. Acoustic: noise pollution can cause or exacerbate stress; mental health and cognition problems, including memory impairment and attention deficits; childhood learning delays.  Acoustic stimuli such as music or ambient noise can significantly affect physiological and psychological health in humans. Specifically, music therapy exhibits promising effects on treatment of neurological disorders such as Alzheimer’s disease (AD) and Parkinson’s disease (PD). Auditory intervention affects an organism, encompassing modulation of immune responses, gene expression, neurotransmitter regulation and neural circuitry. As a safe, cost-effective and non-invasive intervention, music therapy offers substantial potential in treating a variety of neurological conditions.  More than 30% of research respondents considered their awareness of sounds when out and about in public spaces during darkness is important.  People feel less secure wherever sensory input – such as vision – is restricted, through poor lighting or in cramped spaces.
    4. Thermal Comfort: Thermal comfort impacts:
      1. Increased stress and anxiety: High temperatures can lead to discomfort, irritability, and frustration, which can increase stress levels.
      2. Depression and Seasonal Affective Disorder (SAD): Cold environments, especially during the winter months, are linked to depression, particularly in those with seasonal affective disorder. The lack of sunlight and extended darkness can disrupt circadian rhythms, reduce serotonin levels, and negatively affect mood.
      3. Social isolation: Cold weather often discourages outdoor activities and socializing, which can lead to loneliness and feelings of isolation. Lack of social interaction is a risk factor for mental health conditions like depression.
      4. Physical discomfort: Being exposed to cold can cause physical discomfort, such as numbness or shivering, which may contribute to heightened stress or anxiety levels.  On the other hand, a comfortable and stable thermal environment can promote better mental health by improving sleep quality, reducing stress, and enhancing overall mood and cognitive function.
    5. Lighting: Lighting impacts:
      1. Natural Light: Exposure to natural sunlight helps regulate our circadian rhythms, which play a key role in sleep-wake cycles and mood regulation. Sunlight triggers the production of serotonin, a neurotransmitter that improves mood and helps with focus. Lack of natural light, especially in winter, can lead to conditions like Seasonal Affective Disorder (SAD), which is a form of depression linked to changes in seasons and decreased sunlight exposure.
      2. Artificial Light: Poor or excessive artificial lighting can negatively affect mental health. For example, harsh, fluorescent lighting in workplaces or homes can cause eye strain, headaches, and irritability. On the other hand, dim lighting can sometimes promote relaxation but can also make people feel sluggish if it's too dark for extended periods.
      3. Blue Light: Exposure to blue light, especially from screens (phones, computers, TVs), in the evening can disrupt sleep by interfering with melatonin production. This can lead to poor sleep quality, which is strongly linked to mood disorders like anxiety and depression.
      4. Light Temperature: The color temperature of lighting also matters. Warm lighting (yellow or orange tones) tends to be more relaxing and is ideal for evening use. Cool lighting (blue or white tones) is often associated with alertness and productivity, making it suitable for daytime or work settings.
      5. Lighting in Environment: The overall ambiance created by lighting in a space can influence how a person feels. Bright, well-lit spaces are often associated with positive energy and productivity, while dim or poorly lit spaces can feel isolating or depressing.
  3. Infectious Disease Transmission: Ventilation rate, indoor air quality, lighting, and thermal conditions can impact the spread of infectious diseases.
    1. Ventilation rates: Per ASHRAE “Infectious Aerosols” Position Document, “Exposure to infectious aerosols is an important factor in the transmission of infections in indoor environments between a source and a susceptible individual.  Engineering controls demonstrated to reduce the risk of exposure to infectious aerosols include dilution with outdoor air provided by mechanical or natural ventilation, filtration of indoor air, indoor airflow patterns, and disinfection by germicidal ultraviolet light and other technologies proven to be effective and safe.”  ASHRAE 241, “Control of Infectious Aerosols”, has Equivalent Clean Air refers to a metric within the ASHRAE Standard 241, which defines the theoretical flow rate of pathogen-free air needed to significantly reduce the risk of disease transmission in a space, achieved by combining ventilation, filtration, and air cleaning technologies, essentially representing the "clean air" delivered to an occupied area considering all these factors; it is expressed as an "Equivalent Clean Airflow Rate" (ECAi) and is calculated based on the specific space and its occupancy level.
    2. IAQ: Pollutants in the air, e.g. PM 10, PM 2.5 and carry viruses to travel longer distances.  Evidence supports a clear association between air concentrations of some pollutants and human respiratory viruses interacting to adversely affect the respiratory system.
    3. Light: Sunlight played a significant role in infection control and preventing the spread of disease in buildings. Even today, forms of artificial light are effectively being used in hospital settings to reduce infection transmission.  UVC is also used in different settings to mitigate contaminants.
    4. Thermal conditions: Thermal environment, temperature and humidity can impact spread of infectious diseases, as in the Homeland Security  “Estimated  Airborne Decay of SARS-CoV-2 (virus that causes COVID-19)” calculator.  Also, air flow speed and direction and can infectious diseases spread.  In a Korean study, the researchers concluded that “droplet transmission can occur at a distance greater than 2 meters [6.5 feet] if there is direct airflow from an infected person.  The default airflow velocity in Standard 55 is 20 fpm. With sufficient flow and buoyancy-driven by temperature and stack effects, pathogens could travel 10 ft in 30 seconds.
  4. Sleep Quality:  IEQ can impact sleep quality.  Per ASHRAE “Ventilation, IEQ and Sleep Quality in Bedrooms” Residential Issues Brief, “A 2018 review attempted to define environmental conditions in sleeping environments for optimal sleep quality and proposed temperature and humidity ranging generally between 17-28 °C and 40-60% RH, all forms of noise being less than 35 dB, complete darkness and avoidance of blue light immediately before and during sleep, ventilation using sea-level air quality, and passive design using architectural features to incorporate the above elements into bedroom design.”   Sleep serves as a critical indicator of an individual’s physical, psychological and social health (Clement-Carbonell et al., 2021). Adequate sleep can regulate emotions, consolidate memory, enhance learning ability, and promote overall well-being (Rasch and Born, 2013; Papalambros et al., 2017; Ramar et al., 2021). Insufficient sleep not only increases the risk of obesity and cardiovascular diseases, but also triggers anxiety, depression and other mental disorders, leading to a decline in cognitive performance (Ward et al., 2014; Muto et al., 2016; Di Muzio et al., 2020; Scott et al., 2021). The Sleep Ambient Music Intervention can be an effective therapeutic measure for improving sleep quality and mental health (Loewy, 2020; Chen et al., 2021).
    1. IAQ and sleeping quality: Per ASHRAE “Ventilation, IEQ and Sleep Quality in Bedrooms” Residential Issues Brief, “Good air quality, especially the reduction of pollutants (e.g., carbon dioxide, volatile organic compounds, particulate matter, odor, etc.), can help individuals sleep more soundly. Poor air quality can lead to symptoms like nasal congestion, coughing, and difficulty breathing, disrupting sleep”.
    2. Light and sleeping quality: Light plays an important role in the function of the nervous and endocrine systems and the secretion of hormones such as melatonin. Melatonin is released by the pineal gland in a 24-h cycle according to how much light is received, regulating the body’s circadian rhythm. In regular sleep-wake cycles, the hormone is highest at night in the dark promoting healthy sleep and lowest during daylight promoting alertness. Disruption to these rhythms caused by a lack of daylight exposure during the day and exposure to bright lights during the night constitutes as improper light exposure which affects health.
    3. Thermal Comfort
      1. Core body temperature: During sleep, the body naturally cools down. A cooler environment supports this process, making it easier to fall asleep and maintain restful sleep throughout the night.
      2. Hot environments: When it's too warm, your body struggles to cool down. This can lead to tossing and turning, dehydration, and restlessness, which negatively affect sleep quality. It might also prevent you from entering deeper stages of sleep, like REM (rapid eye movement) sleep, which is important for restorative rest.
      3. Cold environments: While cooler temperatures might help you fall asleep initially, extreme cold can cause discomfort or awaken you during the night. If you're too cold, your body may expend energy warming itself, disrupting sleep cycles
    4. Acoustic
      1. Disruptive Sounds (Negative Impact) - Loud or sudden noises (e.g., traffic, barking dogs, construction sounds) can disrupt sleep cycles, causing you to wake up multiple times throughout the night or even prevent you from falling asleep entirely.  Noise can cause micro-awakenings, breaking your sleep into fragmented cycles, preventing you from reaching deep, restorative sleep stages like REM.Noise that disrupts your sleep can raise stress levels, leading to the release of stress hormones (like cortisol), which can make it harder to relax and fall asleep the next night.
      2. White Noise (Neutral or Positive Impact) - White noise or background sounds, such as a fan, air purifier, or white noise machine, can mask disruptive environmental sounds, creating a more consistent sleep environment
      3. Music or Nature Sounds (Positive Impact) - Soft, calming music can promote relaxation and help the brain transition into a sleep-ready state. This is especially helpful if you struggle with racing thoughts or anxiety before bed.  Sounds like rainfall, ocean waves, or gentle winds can also promote a sense of calm and help lower heart rates, making it easier to relax and fall into deep sleep
  5. Premature Death, and DALY, Mortality, and Long Term Issues:
    1. Acoustic and DALY: The World Health Organization (WHO) estimates that at least 1.6 million healthy life years are lost every year in western European countries alone due to the environmental noise (Kempen et al., 2018). In an earlier publication from the (WHO, 2011), it was estimated that in western Europe, 61,000 disability adjusted life years (DALYs) were lost to noise-associated ischemic heart disease, 45,000 to cognitive impairment in children, 903,000 to sleep disturbance, 22,000 to tinnitus, and 587,000 to annoyance.
    2. Light and Mortality Risk: This study predicted mortality risk from lighting. Individuals with brighter day light had incrementally lower all-cause mortality risk, and those with brighter night light had incrementally higher all-cause mortality risk, compared to individuals in darker environments. Individuals with lower circadian amplitude, or later circadian phase had higher all-cause mortality risks. Daylight, night light, and circadian amplitude predicted cardiometabolic mortality, with larger hazard ratios than for mortality by other causes. Findings were robust to adjustment for age, sex, ethnicity, photoperiod, and sociodemographic and lifestyle factors. Minimizing night light, maximizing day light, and keeping regular light-dark patterns that enhance circadian rhythms may promote cardiometabolic health and longevity.  Exposure to light at night, particularly brighter nights, has been linked to a 21% to 34% higher risk of premature death compared to those who experience darker nights, while brighter days are associated with a 17% to 34% lower mortality risk.
    3. Air Pollution: If a study shows that exposure to indoor air pollution (e.g., from cooking with solid fuels) causes 1,000 premature deaths and 5,000 cases of chronic respiratory diseases in a population.  The total DALY would represent the health burden associated with this exposure.  For premature deaths (YLL), if each death occurs at age 60 and the expected life expectancy is 80, this would contribute 20 YLL per death.  For chronic diseases (YLD), each case of chronic respiratory disease would be assigned a disability weight based on the severity of the disease and the number of years the person lives with.  Each year, 3.2 million people die prematurely from illnesses attributable to the household air pollution caused by the incomplete combustion of solid fuels and kerosene used for cooking (see household air pollution data for details).  The Environmental Protection Agency (EPA) notes that long-term exposure to indoor air pollutants can increase the risk of mortality from respiratory diseases by 10-20%.  In the year 2016, ambient air pollution was responsible for 4.2 million deaths. Worldwide, ambient air pollution is estimated to cause about 16% of the lung cancer deaths, 25% of chronic obstructive pulmonary disease (COPD) deaths, about 17% of ischaemic heart disease and stroke, and about 26% of respiratory infection deaths.
    4. Air Pollution in Homes: In this study, estimated population DALYs of chronic air contaminant inhalation in U.S. residences are indicated in below figure:

 Morantes G, Jones B, Molina C, Sherman MH. Harm from Residential Indoor Air Contaminants. Environ Sci Technol. 2024 Jan 9;58(1):242-257. doi: 10.1021/acs.est.3c07374. Epub 2023 Dec 27. PMID: 38150532; PMCID: PMC10785761. Source: National Library of Medicine.

Productivity and Performance

IEQ and Productivity

  • Enhanced indoor environmental quality improves cognitive function by between 61% to 101%, depending on the extent of improvements.
  • Better ventilation, lighting, and environmental quality results in an NPV of $37 to $55 per square foot as a result of productivity gains from less sick time and greater worker productivity.

Importance of Staffing Cost


Source: Health, Well-being & Productivity in Offices, World Green Building Council, Sept. 2014 [WGBC, 2014]

  1. Cognitive Function and Productivity:
    1. A 2000 study suggested for the United States, the estimated potential annual savings and productivity gains are $6 to $14 billion from reduced respiratory disease, $1 to $4 billion from reduced allergies and asthma, $10 to $30 billion from reduced Building-Related Illness symptoms, and $20 to $160 billion from direct improvements in worker performance that are unrelated to health. Productivity gains that are quantified and demonstrated could serve as a strong stimulus for energy efficiency measures that simultaneously improve the indoor environment.  The estimated benefits regarding US were a 1.1% average increase in performance in 12.4 million workers, an 18.8% average decrease in Building-Related Illness symptoms in 12.4 million workers, and 10 million days of avoided absence.$9-14 billion economic benefit associated with increasing ventilation rates to 32 cfm per person.  Numerous studies have indicated that the physical environment of healthcare settings is closely tied to staff well-being, productivity, and satisfaction.  Two studies have mentioned that offices with improved indoor environment can increase the productivity of occupants by more than 20%, which corresponds to more than GBP 130 billion per year in UK.
    2. IAQ:
      1. General ventilation can improve Staff Productivity => $410 per sq. m.  Studies have pegged that improved IAQ could result in an 8 - 10% boost in employee productivity. The World Green Building Council estimates that if staff productivity improves by even a conservative 5% because of improved IAQ, that alone would be worth $410 per sq m. (₹ 26,185 per sq m)
      2. Another study by Harvard calculates the benefit to a company as a result of improved cognitive scores and decision-making performance. According to the study, when ventilation was increased from 20 cfm/person to 40 cfm/person, it corresponded to a $6500 change in a typical office worker’s productivity.  Possible ROI = 120%
      3. The relationship between air pollution and the productivity of individuals at a large call center in China was studied. A 10-unit increase in the air pollution index decreases the number of daily calls handled by a worker by 0.35 percent. The analysis also suggests that these productivity losses are largely linearly increasing in pollution levels.
      4. Seminal research in 2003 identified 15 studies linking improved ventilation with up to 11% gains in productivity, as a result of increased outside air rates, dedicated delivery of fresh air to the workstation, and reduced levels of pollutants.  A meta-analysis in 2006 of 24 studies – including 6 office studies – found that poor air quality (and elevated temperatures) consistently lowered performance by up to 10%, on measures such as typing speed and units output. This analysis appeared to demonstrate that the optimum ventilation rate is between 20 and 30 litres/second (l/s).
      5. In a 2011 lab test which mimicked an office, a range of office-related tasks were carried out with the presence of airborne VOCs. Increasing ventilation from 5l/s to 20l/s improved performance by up to 8%. The same study estimated the value of increased ventilation to be $400 per employee per year
      6. “Ventilation and Performance in Office Work”, suggested there is positive relative performances with increase ventilation rateSeppänen, O., Fisk, W.J., & Lei, Q. (2006). Ventilation and performance in office work. Indoor air, 16 1, 28-36 . [Source: https://www.semanticscholar.org/paper/Ventilation-and-performance-in-office-work.-Sepp%C3%A4nen-Fisk/488944debb027af93cb25f5741b38a8fe7fea626]

      7. Another study based on ventilation, the scenarios include increasing ventilation rates when they are below 10 or 15 l/s per person, adding outdoor air economizers and controls when absent, eliminating winter indoor temperatures >23°C, and reducing dampness and mold problems.   The estimated benefits of the scenarios analyzed are substantial in magnitude, including increased work performance, reduced Building-Related Illness symptoms, reduced absence, and improved thermal comfort for millions of office workers. The combined potential annual economic benefit of a set of nonoverlapping scenarios is approximately $20 billion.
      8. In this study, from both cross sectional and intervention studies, of an association of increased student performance with increased ventilation rates. There is evidence that reduced respiratory health effects and reduced student absence are associated with increased ventilation rates.
        Indoor Air. 2011 Oct;21(5):357-67. doi: 10.1111/j.1600-0668.2011.00719.x. Epub 2011 May 4.
        Source: Published in Indoor Air Journal at https://doi.org/10.1111/ina.12403
    3. Thermal Comfort: 
      1. When temperatures are low, employees made 44% more mistakes than at optimal room temperature.
      2. For US, in this LBL Study, estimated $3.4 billion annual economic benefit, with $0.4 billion implementation costs, through integration of thermal occupant controls
      3. For US, in this LBL study, estimated $2 billion estimated annual value of work performance gains from avoiding high temperatures in the winter.
      4. Temperature Variations: This temperature fluctuation study suggested by cyclic fluctuating air temperature demonstrates that the thermal dissatisfaction rate for cyclic fluctuating air temperature control between 26°C–28°C is lower than that for constant air temperature control at 26°C, while consuming less energy. Moreover, occupant stress levels measured by salivary alpha-amylase, and subjective fatigue levels under cyclic fluctuating air temperature show that similar or even lower distinct results can be achieved with fluctuating air temperature control compared with constant air temperature control.
      5. Dynamic Thermal Comfort/Alliesthesia: The psychophysiological principle of thermal alliesthesia operates within the thermoneutral zone, making it equally relevant to quotidian indoor environments as it is to the extremes found in traditional physiological research. Non-steady-state built environments can potentially offer spatial alliesthesia through carefully managed contrasts between local and mean skin temperature trends. Transitional zones are suggested as design solutions.  Intensity of thermal pleasure increases proportional to thermal load incurred
      6. “Personal Environment” - A 2006 study tested effectiveness of adjustable desk mounted personalized air supply devices on perceived air quality. Greater satisfaction with air quality was reported with desk-mounted devices despite ventilation rates being the same. Similarly, providing individuals with personal control over light levels with dimmers in offices can lead to improvements in satisfaction and mood. Subsequent research added comfort, improved motivation, and greater ease of task performance to this list of benefits“Personal Control”, if an office worker has more control over their environment, they tend to be more satisfied as a result. One study found that individual control over temperature (in a 4°C range) led to an increase of about 3% in logical thinking performance and 7% in typing performance. Another suggests up to 3% gains in overall productivity as a result of personal control of workspace temperature.
      7. Thermal Comfort:  An analysis in 2006 of 24 studies on the relationship between temperature and performance indicated a 10% reduction in performance at both 30C and 15C compared with a baseline between 21C and 23C, leaving little doubt as to the impact thermal comfort has on office occupants. A more recent study in a controlled setting indicated a reduction in performance of 4% at cooler temperatures, and a reduction of 6% at warmer ones.
      8. In California,  without air conditioning, a 1°F hotter school year reduces that year's learning by 1 percent. Hot school days disproportionately impact minority students, accounting for roughly 5 percent of the racial achievement gap, according to UCLA research.
      9. Cooling system replacements boosted math scores by 3 percent of a standard deviation while heating system replacements led to a rise of 4 percent.
    4. Visual
      1. Lighting and Performance: Studies of office worker performance have shown that those with the best possible view of natural light performed between 10% and 25%1 better on tests of mental function and memory recall. On the other hand, those with poor views or no view at all (think high cubicle partitions, heavy glare, basement offices etc.), reported increases in fatigue and decreases in overall speed of performance. These variables can be controlled with circadian lighting design. Incorporating daylighting in the architecture can boost not just the performance of a building, but of those who occupy it as well.
      2. A comprehensive study conducted measurements of the physical environment and occupant satisfaction for 779 workstations in 9 different buildings, and suggested that lack of access to a window was the biggest risk factor for dissatisfaction with lighting.
      3. A study by neuroscientists suggested that office workers with windows received 173 percent more white light exposure during work hours, and slept an average of 46 minutes more per night. Workers without windows reported poorer scores than their counterparts on quality of life measures related to physical problems and vitality, as well as poorer outcomes on measures of overall sleep quality, sleep efficiency, sleep disturbances and daytime dysfunction.
    5. Acoustic
      1. A meta analysis finds reading comprehension scores in quiet classrooms were 0.80 points higher than children in noisier classrooms. Meta-analysis of the impact of 1 dB (dB) increase in environmental noise on reading and language abilities decreases performances. A meta-analysis from 3 studies found higher odds of cognitive impairment in people aged 45 + with higher residential noise exposure. After qualitative synthesis of remaining studies, there was high quality evidence for an association between environmental noise and cognitive impairment in middle-to-older adults, moderate quality evidence for an association between aircraft noise and reading and language in children, and moderate quality evidence against an association between aircraft noise and executive functioning in children. Generally the literature was supportive for other cognitive outcomes, but with low or very low-quality evidence.
      2. A study in 1998 found that there was up to a 66% drop in performance for a ‘memory for prose’ task when participants were exposed to different types of background noise. A follow-up study by the same authors in 2005 found that 99% of people surveyed reported that their concentration was impaired by office noise such as unanswered phones and background speech.
      3. The detrimental effect of ambient noise on the short-term memory processes was commonly found in a workplace setting. It could lead to possible causes for reduced efficiency in performing cognitive tasks.
      4. A good acoustic environment ensures the occupants’ psychological and physiological fitness and boosts concentration. In a 2011 laboratory experiment in Sweden, Jahncke et al. found increased performance on memory tasks and reduced tiredness in low-noise (39 dBA) work environments as compared to high-noise (51 dBA) work environments. Danielsson and Bodin identified that employees in individual closed offices reported higher health status, such as sleep quality and satisfaction rates, than those in open-plan offices. The types of offices, open or closed, and associated acoustic characteristics, such as privacy and noise disturbance, could have detrimental effects on occupants’ wellbeing and impact occupants’ job performance and subjective satisfaction.
      5. In a research conducted by The University of Arizona -"The results showed that when a worker's environmental sound level was above 50 decibels, each 10-decibel increase was related to a 1.9% decrease in physiological well-being. But when office sound was lower than 50 decibels, each 10-decibel increase related to a 5.4% increase in physiological well-being."
      6. Occupants’ self-rated job performance shows that over 60% of occupants in cubicles think acoustics interfere with their ability to get their job done


        Jensen, K., & Arens, E. (2005). Acoustical quality in office workstations, as assessed by occupant surveys. UC Berkeley: Center for the Built Environment. Retrieved from https://escholarship.org/uc/item/0zm2z3jg 

  2. Job Satisfaction - This research investigated and suggested that improving IEQ of offices is likely to have positive impact on job satisfaction and productivity of both professionals and academics.
  3. Attracting and Retaining Tenants/  Differentiator - Sustainability efforts which include improved IAQ increase employee satisfaction and thus improve retention as well as help attract talent.  Interface Inc. found that 71% of full-time workers consider a company’s commitment to sustainability an important criterion when evaluating a new workplace.  In a survey of its employees.  For more examples see SRER Report: Integrated Alternative Workplace Strategies (AWS), 2011; and SRER Report: More Sustainable Leased Space, 2011.
  4. Nature and IEQ: Research shows that exposure to natural environments has substantial benefits for improving psychological well-being (e.g., positive effect) and cognitive performance (e.g., working memory), which have the potential to improve learning performance. A prior study suggested that exposure to nature sounds (e.g., the sounds of birds, rainfall, and waves) through a mobile application in daily life can reduce university students’ mental fatigue and improve their cognitive performance.
    1. Playing natural sounds such as flowing water in offices could boosts worker moods and improve cognitive abilities in addition to providing speech privacy, according to a new study from researchers at Rensselaer Polytechnic Institute.
    2. Study on trees in urban areas suggested it has the effect of making people feel $10,000 richer or similar effect to 7 years younger.
    3. In this paper below, natural sound was rated as more restorative than industrial noise.

      Haga A, Halin N, Holmgren M, Sörqvist P. Psychological Restoration Can Depend on Stimulus-Source Attribution: A Challenge for the Evolutionary Account? Front Psychol. 2016 Nov 23;7:1831. doi: 10.3389/fpsyg.2016.01831. PMID: 27933011; PMCID: PMC5120095. 

  5. Absenteeism: Cost of Absenteeism is estimated below in 2015

    Source: Health, Well-being & Productivity in Offices, World Green Building Council, Sept. 2014 [WGBC, 2014]
    1. In this study, the effects of improved indoor environmental quality (IEQ) on perceived health and productivity in occupants who moved from conventional to green (according to Leadership in Energy and Environmental Design ratings) office buildings. In 2 retrospective-prospective case studies we found that improved IEQ contributed to reductions in perceived absenteeism and work hours affected by asthma, respiratory allergies, depression, and stress and to self-reported improvements in productivity. These preliminary findings indicate that green buildings may positively affect public health.
    2. IEQ: This study examined whether the combined effect of poor IEQ and self-reported psychosocial stressors (low social support from supervisors and experiences of injustice) increase the risk of employees’ long-term sickness absence (more than 10 days) in comparison to employees who report only poor perceived IEQ and no psychosocial stressors. Results: After background variables were included in the model, employees who reported poor IEQ and low social support had higher rates of long-term absence than those who reported poor IEQ and high support. Similarly, employees who reported poor IEQ and experiences of injustice had higher rates of absence than those who reported poor IEQ and no injustice. Conclusions: Employees who reported poor perceived IEQ and a psychosocial stressor had higher rates of long-term sickness absence one to three years later, in comparison with those who report only poor perceived IEQ and no psychosocial stressors. These findings demonstrate the importance of taking account of psychosocial stressors as well, when resolving indoor environmental problems.
    3. IAQ: Reduced absences may also be a key indicator of the benefits of good indoor air quality for businesses. Short term sick leave was found to be 35% lower in offices ventilated by an outdoor air supply rate of 24 l/s compared to buildings with rates of 12 l/s in a 2000 study . The same study estimated the value of increased ventilation to be $400 per employee per year.
    4. Lighting and View: A study in 2011 investigated the relationship between view quality, daylighting and sick leave of employees in administration offices of Northwest University Campus. Taken together, the two variables explained 6.5% of the variation in sick leave, which was statistically significant.
    5. Filtration  in this study, such as increased ventilation and higher grade air filtration (MERV-13 filters or higher) have been shown to result in a 9-20% annual reduction in sick leave. When implemented appropriately, these improvements can result in up to 60x return on investment in the form of worker reliability and productivity.
    6. While enhanced productivity solely as a function of improved health is still to be quantified, studies have calculated that employees tend to take 30% fewer sick leaves as a result of improved IAQ.
  6. Recovery Time:
    1. In this study, circadian lighting has shown to have useful applications in the healthcare industry as well, benefiting patients and institutions alike by actually decreasing average length of patient stays. A recent study published in Building and Environment reported findings that patients with direct access to morning light were seeing their stays shortened by anywhere from 16% to 41%.
    2. Florence Nightingale, renowned as the mother of nursing, advocated for care in environments with natural light, ventilation, cleanliness, and basic sanitation, believing that such conditions promote quicker recovery.
    3. Researchers have uncovered a strong connection between health outcomes and the indoor environment where individuals live or receive treatment in hospitals.  In 2012, it was estimated the economic benefits to the US of providing patients with views of nature to be US$93 million/year

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