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Built Environment

image from Rich Johnstone at Creative Commons

Our built environment includes all the human-made physical spaces where we live, recreate and work. These include our buildings, furnishings, open and public spaces, roads, utilities and other infrastructure. These structures and spaces affect our health by bringing pollutants into our environments and by allowing or restricting access to physical activity, transportation and social interactions.

Indoor Environments and Health

Because close to 90 percent of time is spent indoors on average in developed countries,1 and because indoor spaces in developing nations are often greatly impacted by burning solid fuels, indoor environments have a huge potential to influence health worldwide.2 The features of our indoor environments that can affect our health and well-being include noise, temperature, humidity and mold, light, air quality, lead paint, electromagnetic and radiofrequency radiation and water quality.

Air Quality

Indoor environments can concentrate some pollutants such that indoor levels can be many times higher than outdoor levels.3 Poor indoor air quality may increase rates of asthma, allergies, and infectious and respiratory diseases.4

Radon

content from ToxipediaRadon is a radioactive noble gas formed by the decay of uranium, thorium and radium; soils and rocks containing high levels of uranium, such as granite, phosphate, shale and pitchblende are natural sources of radon. Radon is continually being formed in soil and released to air as a result of the extended half-lives of uranium and radium and their abundance in the earth's surface. Outdoors, radon exposure is not a concern because the radon is rapidly diluted to low levels by circulating air. However, radon seeps through cracks and gaps in buildings and homes, increasing indoor concentrations to toxic levels in buildings that are not adequately ventilated. 

Radon is the second leading cause of lung cancer after cigarette smoking, estimated to cause between three and 14 percent of all lung cancers in a country, depending on the national average radon level and smoking prevalence.5 The US Environmental Protection Agency (EPA) and the Surgeon General's office estimate radon is responsible for more than 20,000 lung cancer deaths each year in the US6 and is the leading cause of lung cancer in nonsmokers.7 Smoking multiplies the risk of lung cancer from radon such that smokers are estimated to be 25 times more at risk from radon than non-smokers.8

Carbon Monoxide

wood stove

 

image from madalse at Creative Commons

When fuel is burned in in cars or trucks, small engines, stoves, lanterns, grills, fireplaces, gas appliances or furnaces, fumes containing carbon monoxide are produced. Without adequate ventilation indoors, carbon monoxide can build up, poisoning people and animals. Carbon monoxide poisoning is characterized by headache, dizziness, weakness, upset stomach, vomiting, chest pain and confusion, and is compared to flu symptoms. Higher concentrations are lethal.9

Particulate Pollution

content from ToxipediaParticulate matter (PM) in air comes from dust, fly ash, soot, smoke, pollen, spores, fibers, pet dander, aerosols, fumes, mists and condensing vapors that can be suspended in the air for extended periods of time.10

Indoor sources of PM:

  • smoky cigar

     

    image from Brandon at Creative Commons

    Cooking
  • Burning of fuels, candles and other materials
  • Smoking
  • Some electronics, such as laser printers

Particulates are often characterized by size:

  • PM10: inhalable particles with diameters that are generally 10 micrometers and smaller; a micrometer is 1/1000000 of a meter, or about 1/25400 of an inch
  • PM2.5: fine inhalable particles with diameters that are generally 2.5 micrometers and smaller.11

Exposures to particulate matter impact many aspects of health, including lung development and health, asthma, cardiovascular health, fetal growth and preterm birth, and kidney cancer:12 More about the health impacts of particulates is on our Air Quality webpage.

The World Health Organization estimates that three billion people cook and heat their homes using open fires and simple stoves burning biomass and coal. Particulate matter is a grave issue in these homes, with exposures particularly high among women and young children who spend the most time near the domestic hearth. Health effects of these exposures:

  • cooking over an open fire

     

    image from Chris Beckett at Creative Commons

    Annually, more than 4 million people die prematurely from illness attributable to the household air pollution from cooking with solid fuels.
  • More than 50 percent of premature deaths due to pneumonia among children under 5 are caused by the particulate matter (soot) inhaled from household air pollution.
  • Exposure to household air pollution leads to 3.8 million premature deaths annually from noncommunicable diseases including stroke, ischemic heart disease, chronic obstructive pulmonary disease (COPD) and lung cancer.13

Chemicals

content from ToxipediaChemicals can contribute to poor indoor air quality:14

  • Off-gassing from paints and furniture finishes can contain volatile organic compounds (VOCs), which are associated with rhinitis.
  • Some plastics, such as vinyl shower curtains and flooring, and also air fresheners, new carpets, dryer sheets, and items dry-cleaned with PERC can off-gas toxic chemicals. High-heat cooking with some non-stick cookware may release perfluorinated chemicals into the air.
  • Furnishings with foam components can contain high levels of flame retardants that migrate into air. Some activities, such as gymnastics, can bring people into higher contact with these chemicals.15
  • Some hobbies and crafts introduce fumes from glues, paints, solvents and other substances into the air.
  • Some cosmetics, especially nail polishes, polish removers and perfumes, can contribute toxic chemicals to indoor air. Some hair dyes and treatments also contain toxic chemicals.
  • Asbestos used in building materials can degrade fine particles into the air if not covered appropriately. Asbestos exposure a serious risk during building renovations.
  • Carbon dioxide from our own breathing can build up in unventilated indoor spaces; a 2015 study found a decline in cognitive performance with elevated levels of carbon dioxide and VOCs.16
  • Degrading lead paint can become fine particles that can be inhaled. Burning candle wicks that contain lead can also raise indoor lead concentrations to levels toxic to children. A 2010 investigation found elevated lead levels in most children's bounce houses in California's Bay area, leading to a lawsuit.17
  • Mercury-containing compact fluorescent light bulbs release small amounts of mercury if broken.
  • Some glues used in particle board may contain chemicals that produce formaldehyde, a known carcinogen. Glues in wallpaper and flooring can also contribute toxic chemicals to indoor air.
  • Some cleaning solutions (especially those containing ammonia or chlorine bleach) can release toxic chemicals that can irritate airways and cause bronchitis, rhinitis or asthma attacks.

These are examples of chemicals frequently found in homes. Indoor workplaces, especially those involving manufacturing, can have many further chemicals in the air. Industries that produce or use large quantities of the items listed above would certainly need to address indoor air quality to promote optimal health and safety.

Water Quality

The built environment's plumbing infrastructure can affect water quality, as 2015 events in Flint, Michigan, taught the world. Lead pipes or solder either within buildings or connecting buildings to water mains can contaminate water coming into homes with enough lead to cause permanent harm to children's brains and also affect adult health.

Chlorine and other disinfectants added to water can interact with other materials in water to create disinfectant by-products, such as trihalomethanes and haloacetic acids. These by-products are associated with some forms of cancer, reproductive health impacts and neural tube defects in fetuses.18 Indoor chlorinated swimming pools can be a significant source of exposures to chlorine and by-products.19

Fluoride may be added to municipal water supplies, and in some places occurs naturally in water. High levels can have health impacts, including dental fluorosis, joint pain, bone deformity, and adverse cognitive development in children.20

Lead Paint

content from ToxipediaLead was used as an additive in paint for many years to speed drying, improve the finish and resist moisture. In 1922, the League of Nations banned lead-based paint due to mounting health concerns, yet the United States did not curtail its use in homes until the Lead-Based Paint Poisoning Prevention Act was enacted in 1971. Lead paint use continued in buildings until 1978.

EPA graphic on lead paint in homes

graphic from the US Environmental Protection Agency21

Small chips of flaking paint can adhere to hands or dusty surfaces and then be transferred to food and ingested. Crawling children and toddlers are especially likely to encounter paint chips on floors, and they often put their hands in their mouths.

Lead is toxic to people of any age but is especially damaging to fetuses and young children. Very small amounts of lead cause permanent brain and neurological damage to children. Other health impacts include reproductive health effects, anemia, renal disease, cataracts, coronary artery disease, hearing loss, hypertension, psychiatric disturbances, seizures and more, as described on our Lead webpage.

Pesticides

Pesticides are often used to control insects, rodents and other pests within buildings, where residues on surfaces and in the air can expose occupants. Various pesticides are associated with cancer, neurodevelopmental impacts, reproductive impacts, asthma attacks, immune suppression, hearing loss, psychiatric disturbance and other effects.22

PCBs

Polychlorinated biphenyls, commonly known as PCBs, were phased out by a 1976 US federal law but remain within many buildings built before then. PCBs were used in hundreds of industrial and commercial applications, such as in electrical equipment. In schools, PCBs may be found in caulk, electronics, fluorescent light ballasts and other building materials.23

PCBs can cause skin conditions such as acne and rashes and may impact neurodevelopment, reproductive health and immune system functioning.24

Dirty Electricity

Relatively clean 60 Hz (North America) or 50 Hz (most of the rest of the world) AC current is delivered to our homes and buildings. To save energy, electronic devices including computers, televisions, stereos, CFL and low-voltage lighting use transformers and power supplies to convert this current to low-voltage power. These transformers "chop-up" conventional AC voltages, using electricity in short bursts as opposed to a smooth continuous flow of current. This constant stopping and starting of the electrical current causes what engineers call electrical feedback, in technical terms known as "electrical transients." Because AC current switches direction constantly, any AC appliance also creates electrical harmonics.

Together these transients and harmonics are called electromagnetic pollution, often subdivided into excessive EMF, dirty electricity, and electrosmog, depending on the frequency or mix of frequencies. This electrical pollution rides along on a building's electrical system with the ability to contaminate an entire home and even buildings and homes nearby.25

There is limited evidence that dirty electricity can impact health, but a 2016 review concluded that "The available evidence for DE [dirty electricity] as an exposure affecting human health at present does not stand up to scientific scrutiny."26

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Electromagnetic Radiation and Radiofrequency Radiation

We experience electromagnetic fields (EMFs) as heat, light, magnetic attraction/repulsion and  electricity. EMFs are the basis of all chemical and biochemical reactions, including those in our bodies. Exposures to EMFs can be of several types:

  • Direct exposure through conduction, such as touching a wire or other conductive path
  • Indirect exposure through convection, such as breathing in ionized particles
  • Remote exposure from radiated fields, whether nearby magnetic fields or more distant electric fields from wiring, antennas, metal surfaces and so on.27

Since the early 20th century, environmental exposure to human-made EMFs has been steadily increasing as growing electricity availability, advancing technologies and changes in social behavior have created more and more artificial sources of EMFs.

High-frequency EMFs are produced by mobile phones, WiFi and "smart meters."28 The Bioinitiative Report 2012 reviewed more than 1800 additional studies since the 2007 report and concluded that biological effects "are clearly established and occur at very low levels of exposure to electromagnetic fields and radiofrequency radiation."29 More information about EMFs is on our Radiation Environment webpage.

Humidity and Mold

content from ToxipediaHumidity levels in buildings affect our comfort levels, but of much greater importance is the contribution of high humidity to the growth of mold and some bacteria. All mold needs to thrive is water and a food source, which is readily available in buildings from wood, paper, tile glue, rugs and other textiles, sheetrock and other building materials.

moldy shower area

image from nusltegroup at Creative Commons

Excess water or moisture in indoor environments can accrue from these sources:

  • leaking plumbing
  • inadequately ventilated showers, laundry areas and cooking areas; dishwashers can also create steam
  • seepage into basements and crawl spaces
  • overflow from heavy rain or floods

Symptoms and conditions associated with mold include nasal stuffiness, eye irritation, wheezing or skin irritation. People with serious allergies to molds may have more severe reactions,30 and mold exposures have been found to contribute to asthma incidence and episodes in children.31 Mycotoxins in some types of mold can lead to inflammation and possibly chronic illness.32 Estimates of costs for illness and mortality related to mold and dampness exceed $20 billion (2014 dollars) just within the US.33

Keeping the indoor humidity below 50 percent—and 37 percent is even better—is recommended to avoid mold growth.34

Noise

noise

 

image from richardoyork at Creative Commons

Noise levels indoors can easily exceed the 85 dB(A) sustained level at which hearing loss occurs.35 Excessive indoor noise can come from appliances, such as hair dryers and kitchen exhaust fans, or from music, television or recreational electronics. Noise from outside buildings can also intrude into indoor spaces: traffic, trains, airplanes, heavy equipment, generators, lawn equipment, fireworks and more.

Designing Buildings to Reduce Noise Pollution36

  • Use double-pane windows.
  • Use sound walls and trees as sound buffers.
  • Orient buildings to refract or reflect traffic-related noise.
  • Use rail transit.
  • Restrict the use of truck and bus idling, especially in neighborhoods.

Lower levels of noise can produce sleep disturbance, cardiovascular effects including heart attacks and stroke, learning impairment, psychophysiological effects, psychiatric symptoms and impaired fetal development. Noise also has widespread psychosocial effects including noise annoyance, reduced performance and increased aggressive behavior.37

Noisy work environments are more concerning than noise at home. Please see The National Institute for Occupational Safety and Health (NIOSH) website for more information about noise and health in workplaces:

Light

computer screens and artificial light

 

image from NASA Johnson at Creative Commons

Artificial light has changed many aspects of human life, from allowing us to be productive long outside daylight hours to reducing the risk of damage and injury from uncontrolled fire. Light has its negative side, however, in disrupting circadian rhythms of sleep and wakefulness. Early research indicates that artificial light, and especially blue light from electronic screens and some energy-efficient bulbs, may contribute to the incidence of chronic disease and obesity.38

Temperature

Our ability to heat and cool indoor environments has a huge impact not only on comfort but on our health. Controlled temperature environments bring these benefits:39

  • Reduce heat's exacerbation of many chronic diseases and, at extreme levels, damage to the brain, heart, lungs, kidneys and liver
  • Reduce heat stroke
  • Reduce hypothermia and its effects on cardiovascular health
  • Reduce deaths from either heat or cold

At the same time, the built environment can create problems by concentrating ambient heat and creating urban heat islands. The annual mean air temperature of a city with one million people or more can be 1.8–5.4°F (1–3°C) warmer than its surroundings. In the evening, the difference can be as high as 22°F (12°C). Indoor temperatures can be considerably greater than in nearby rural areas.40 Dense urban areas without indoor cooling can experience substantial health impacts during heat episodes.

Sick Building Syndrome and Building-related Illnesses

content from Toxipedia"Sick building syndrome" (SBS) describes situations in which building occupants experience acute health effects that appear to be linked to time spent in a building, but no specific illness or cause can be identified. The effects may be localized in a particular room or zone, or they may be widespread throughout the building.

"Building-related illness" (BRI) refers to diagnosable illnesses that can be attributed directly to airborne contaminants in buildings. An example of BRI is Legionnaire's Disease, attributed to specific bacteria.41

Outdoor Built Environments

Transportation

Beginning with the invention of the automobile, and accelerating after World War II, environments from neighborhoods to regions worldwide have been designed or adapted to allow and promote automobile and other vehicle use. These decisions and designs have had far-reaching consequences for communities and societies:

  • sprawl neighborhood

    A sprawling, car-dependent neighborhood in New Jersey; image from Kalzer Rangwala at Creative Commons

    Increased road construction and maintenance
  • Promoted neighborhood sprawl
  • Increased traffic noise, pollution and congestion
  • Increased reliance on petroleum
  • Reduced opportunities for walking and other active transportation

These consequences all have implications for our health. Designing or altering transportation systems to focus on clean community transit and walkability could have far-reaching public health benefits.

Road Construction and Maintenance

More vehicle use generally means more paved roads and parking lots. Building and maintaining roads release toxic fumes42 and involve polluting and noisy heavy equipment. Rain runoff from roads and parking lots impacts water quality and can increase levels of heavy metals in water.43 Asphalt and sealants also impact air quality: a 2010 investigation found that residences adjacent to parking lots with coal-tar-based seal coat have concentrations of PAHs in house dust 25 times higher than residences adjacent to unsealed pavement or asphalt-sealed pavement, and living adjacent to coal-tar-sealed pavement can increase excess lifetime cancer risk as much as 38 times.44

Sprawl

Sprawl, Equity and Employment Opportunities

A 2016 analysis of walkability in the 30 largest US urban areas found that households in walkable areas spend less on transportation (19 percent of income in the most walkable areas compared to 28.6 percent in the least walkable areas). Moderate-income households in highly walkable urban metros also have substantially greater access to employment  opportunities.45

Sprawl is characterized by low-density and single-use residential areas where homes are far from any other destination. The only route between homes and jobs, shopping, schools, places of worship and other frequent destinations may be on a busy high-speed arterial road that is unpleasant or even unsafe for biking or walking. Population density may be too low to support public transit systems. Driving is often the most convenient—or even the only realistic—means of transport.46

As schools, shopping and jobs have become separated from neighborhoods, vehicle use has increased. The separation of schools from neighborhoods is one reason fewer children walk to school.47 However, it's not the only reason, for the percentage of US children living within a mile of school who walked or biked to school dropped from close to 90 percent in 1969 to only 31 percent in 1999.48

Health researchers have found that people who live in areas marked by sprawl-style development tend to be less physically active, weigh more, are more likely to be obese and are more likely to suffer from high blood pressure.49

Increased Traffic

Traffic noise can directly impact health. For example, a 2016 study found that the risk of myocardial infarction (heart attack) rose with exposure to road noise or railroad noise. The association was strongest, and extended to airplane noise, among those whose heart attacks were fatal.50 Traffic noise is also associated with impacts on respiratory and metabolic health.51

polluting car

 

image from Luc at Creative Commons

Air pollution from vehicles includes several pollutant types: fine particulate matter (PM), air toxicants, and volatile organic compounds (VOCs), carbon monoxide and nitrogen oxides which combine to form ground-level ozone (smog). Traffic pollution contributes to poor respiratory and cardiovascular health,52 and it is a factor in preterm birth, low birth weight, miscarriage and stillbirth.53 Early research has connected air pollution to poor cognitive performance, both in children and in elders.54

Traffic pollution is a great concern in developing countries where vehicle ownership is on the rise, especially when vehicles are older and use leaded gasoline or diesel fuels.55

A built environment that locates walkable and open spaces within areas with higher traffic and congestion may increase pedestrians' and cyclists' exposure to vehicle pollution. Siting homes, schools and workplaces near heavy traffic likewise increase the risks of exposures.56

BuiltEnvironmentGraphic

Data from UK, France, Germany and the US;57 click to zoom

Traffic congestion has both direct and indirect costs to societies beyond the pollution it generates. A 2014 investigation of traffic in the United Kingdom (UK), France, Germany and the US found that in 2013 road users spent, on average, 36 hours in gridlock every year in metropolitan areas, predicted to increase by six percent between 2013 and 2030. The value of the direct (time and fuel wasted) and indirect (increased cost of doing business) costs of congested traffic during peak periods in 2013 was estimated at $200.7 billion across all four advanced economies. This study further estimates that vehicle idling releases 15,434 kilotons of carbon dioxide (a key driver of climate change) equivalent into the atmosphere across the UK, France, Germany and the US every year. This output is forecasted to rise by 16 percent between 2013 and 2030.58

Longer driving times and more frequent commuting by car are associated with these health effects:59

traffic jam

 

image from Hamed Saber at Creative Commons

  • Weight gain, even among physically active adults
  • Higher cholesterol levels
  • Higher blood sugar
  • Lower cardiorespiratory fitness
  • Higher continuous metabolic score
  • A higher tendency toward depression, anxiety, and social isolation
  • A greater risk of hypertension
  • More traffic accidents

Reliance on Petroleum

Although there has been some movement toward vehicles that are not powered by fossil fuels, as yet the overwhelming majority of vehicles rely on petroleum products.

The oil and gas industry is the largest industrial source of emissions of volatile organic compounds (VOCs), which contribute to the formation of ground-level ozone. Exposure to ozone is linked to aggravated asthma, increased emergency room visits and hospital admissions, and premature death.60

Toxicants in Crude Oil

Crude oIl contains hundreds of substances. These are some health effects of a few:61

Benzene

Chromium

  • Asthma
  • Bronchitis
  • Cancer
  • Chronic renal disease
  • COPD (chronic obstructive pulmonary disease)
  • Skin ulceration

Mercury

Nickel

Sulfur dioxide

Toluene

Xylene

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Every stage of petroleum production and use impacts health:

  • Exploration, drilling and extraction involve road building, use of heavy equipment (often diesel-powered) and increased vehicle traffic, with health effects described above. A 2016 review of 45 studies found moderate evidence that oil and natural gas extraction increase risks of preterm birth, miscarriage, birth defects, decreased semen quality and prostate cancer.62
  • Refining petroleum releases hazardous toxicants including particulates, sulfur oxides, carbon monoxide, hydrocarbons, benzene, aldehydes and ammonia.63 The trend is for fewer emissions, with reductions of 50 percent or more in sulfur oxides, nitrogen oxides, VOCs and hazardous air pollutant (HAP) emissions from 1990 to 2013.64 The decline of many emissions in the US is attributable to the implementation of the Clean Air Act Amendments of 1970 and 1990.65 However, refinery employees and residents of neighborhoods near and downwind of refineries still suffer disproportionate health impacts from the toxics associated with refining,66 and explosions, accidents and fires at refineries are hazardous to all in the vicinity.
    refinery fire in Richmond, CA

    Refinery fire in Richmond, California; image from nick fullerton at Creative Commons
  • Transporting crude oil and refined petroleum products produces pollution on shipping lanes, at ports, along railways and on highways all along shipping routes.
  • content from ToxipediaOil and fuel spills can and often do happen at any stage of extraction and transporting oil. Crude oil contains hundreds of substances, many of which are known carcinogens and have other health impacts (at right).67 Oil spills can also increase toxicants—and especially polycyclic aromatic hydrocarbon (PAH) and metals—in seafood, contaminating an important food source. The effects of oil dispersants used in cleaning spills on food supply and human health are not yet known,68 but an analysis by Toxipedia staff found several chemicals of high concern to human health among an aggregate list of chemicals found in oil dispersant products that the US Environmental Protection Agency had approved in 2011 for use in an oil spill.
  • Consumption of the final products: Both the vapors from gasoline and the substances produced when it is burned (carbon monoxide, nitrogen oxides, particulate matter, and unburned hydrocarbons) contribute to air pollution.69 Burning petroleum products also releases carbon dioxide, which contributes to climate change. Diesel fuel is used in most freight trucks, trains, buses, boats, and nonroad (farm and construction) vehicles. It is also used in some cars and small trucks, especially in Europe, and in diesel engine generators to generate electricity.70 Diesel fuel produces 15 percent less carbon dioxide than gasoline but emits four times more nitrogen dioxide pollution and 22 times more particulates.71

Opportunities for Physical Activity

Cities that have green spaces, sidewalks, trails and bike lanes promote physical exercise and mental health.72 Health benefits of physical activity include these:73

Children and Adolescents Adults
  • Improved cardiorespiratory fitness
  • Improved muscular fitness
  • Improved bone health
  • Favorable body composition
  • Improved markers of cardiovascular and metabolic health.
  • Lower risk of early death
  • Lower risk of heart disease and stroke
  • Lower risk of high blood pressure and adverse blood lipid profile
  • Lower risk of type 2 diabetes
  • Lower risk of colon and breast cancer
  • Lower risk of metabolic syndrome
  • Prevention of weight gain
  • Weight loss, particularly when combined with reduced calorie intake
  • Improved cardiorespiratory fitness
  • Improved muscular fitness
  • Prevention of falls
  • Reduced depression
  • Better cognitive function (for older adults)
  • Improved health of kidneys, joints and lymphatic system

CDC infographic on the built environment

CDC infographic; click to open a PDF of the infographic

Data from the infographic at right:74

Effects of Environments Limiting Physical Activity

Effects of Environments Promoting Physical Activity

Less physical activity is responsible for 250,000+ US deaths a year. Walkable communities and active transportation can increase physical activity by 150 percent.
Physical inactivity costs the US $120 billion in 2012 alone. Bicycle and pedestrian infrastructure saves $1.20-$3.80 for every dollar invested in the US.
5,000 US deaths per year from pedestrian and bicycle crashes with motor vehicles Separated walkways prevent 88 percent of pedestrian-related motor vehicle crashes.
Road traffic pollution causes 58,000 US deaths per year. Walkable communities generate less pollution by driving 25% fewer miles.

Much of our walking occurs outdoors, and so building walkability into our built environment, in clean and safe spaces, promotes daily walking.75

Other key points about built environments, transportation and physical activity:76

Co-benefit of Walkable Neighborhoods: Greater Social Cohesion

On streets with more traffic, neighbors are less likely to know each other. Walkable communities and communities where more people walk offer opportunities for personal interaction and social involvement. These interactions help strengthen the personal bonds that bring people and communities together, creating more social cohesion.77 See more about this below in Built Environment and Mental Health.

  • Children are more active outside when school playgrounds are available to the public.
  • Walking is the most common form of physical exercise. Safe places to walk near automobile traffic include medians and crosswalks.
  • People who live near trails are more physically active on average.
  • More physical activity promoted by a healthy built environment can reduce medical costs associated with obesity and obesity-related diseases.
  • Fewer children walk or bike to school now than in 1969, dropping from 50 percent to 13 percent.
  • Driving less reduces air pollution.
  • Cities are not equal in the quality of environment they offer, with up to a 10-fold difference in the number of fatalities of pedestrians and bicyclists between cities.
  • Residents of walkable neighborhoods are more likely to meet the Physical Activity Guidelines for Americans. Transit riders are also more likely than drivers to meet the activity recommendations.78

Transportation Safety. One impediment to people's choices to walk and bicycle for transportation is the need for safe sharing of roads with vehicles. An environment designed for automobiles puts more pedestrians and cyclists at risk of being hit compared to one that focuses on bike lanes and safe pedestrian walkways. In 2013 in the US, 4,735 pedestrians were killed and an estimated 66,000 were injured in motor vehicle-related crashes, and the proportion of vehicle-pedestrian incidents resulting in fatalities increased from 2004 to 2013.79 Built environment factors associated with more motor vehicle-pedestrian incidents:80

  • mannequins of killed pedestrians in Chicago

    In 2011, Chicago installed 32 mannequins along Wacker Drive, with each mannequin representing a pedestrian killed in Chicago the year before; image from Kevin Zolkiewicz at Creative Commons.

    Lack of sidewalks and crosswalks
  • Poor lighting
  • Streets with high-speed traffic and/or higher non-highway traffic volume
  • Poorly timed crossing signals
  • More arterial streets without transit
  • More commercial zoning in neighborhoods
  • More total employees in a neighborhood
  • More total residents in a neighborhood
  • More people living in poverty

Energy and Heating

The introduction of electricity to buildings has had a huge positive impact on quality of life and health worldwide. In fact, lack of reliable electric power is a health concern: many parts of the world do not have reliable access to electricity in their health care facilities, impeding their ability to care for patients during night time hours, to operate equipment, store medications and vaccines, manage hazardous waste and even pump water.81 The ways we heat our buildings and power our electricity have widespread impacts on our outdoor environments and health, with huge differences in impacts depending on the sources of electricity.

Coal

As with petroleum, coal causes harm to health at every stage of its production and use.82 A 2011 review estimated that the life-cycle effects of coal and the waste stream generated are costing the US public a third to over one-half a trillion dollars annually.83

open cut coal mine

Open cut coal mine Hunter Valley; image from Max Phillips (Jeremy Buckingham MLC) at Creative Commons

Coal mining leads US industries in fatal injuries and is associated with chronic health problems among miners. Rates of coal worker's pneumoconiosis and progressive massive fibrosis are increasing in the United States despite regulations.84

Communities near coal mines may be adversely affected by blasting, washing, leakage from "slurry ponds", the collapse of abandoned mines, damage done to streams and waterways, and the dispersal of dust from coal trucks during transportation. Slurry injected underground can release arsenic, barium, lead and manganese into nearby wells, contaminating local drinking water supplies.85

Transporting coal adds pollution to the air from diesel locomotive engines and wind-blown coal dust. Occasional spills onto land and waterways pollute those resources.

coal-fired power plant

 

image from Cathy at Creative Commons

Coal combustion releases mercury, particulate matter, nitrogen oxides, sulfur dioxide and dozens of other substances known to be hazardous to human health, as described above. Coal pollutants affect all major body organ systems and contribute to four of the five leading causes of mortality in the US: heart disease, cancer, stroke and chronic lower respiratory diseases. 

  • Respiratory effects include asthma, lung disease and lung cancer, and adverse effects on normal lung development in children.
  • Cardiovascular effects include arterial occlusion (artery blockages leading to heart attacks) and infarct formation (tissue death due to oxygen deprivation, leading to permanent heart damage), as well as cardiac arrhythmias and congestive heart failure. Exposure to chronic air pollution over many years increases cardiovascular mortality.
  • Nervous System Effects include a correlation between coal-related air pollutants and stroke, as well as loss of intellectual capacity, primarily through mercury.86

US Power Plant Impacts, 2010 estimates:87

Health Impact  Annual Incidence Valuation, Millions of Dollars
Mortality  13,200 $96,300
Hospital admissions  9,700 $230
ER visits for asthma  12,300 $5
Asthma attacks 217,600 $11
Heart attacks 20,400 $2,230
Chronic bronchitis 8,000 $3,560
Lost work days 1,627,800 $150

Coal combustion also contributes substantially to climate change, as shown in the graph in the section on renewable energy below.

TVA coal ash disaster scene

Site of the TVA coal ash disaster near Kingston, Tennessee, more than three years later; in 2008 a dike ruptured, releasing enough coal ash to fill a football field nearly a half-mile high. Image from Appalachian Voices at Creative Commons

Storage of post-combustion wastes from coal plants threatens human health: A 2016 inventory by the US Environmental Protection Agency lists 117 High and Significant hazard coal ash ponds in the United States:88

  • High hazard potential classification indicates that failure or misoperation will probably cause loss of human life.
  • Significant hazard potential classification indicates dams where failure or misoperation results in no probable loss of human life, but can cause economic loss, environment damage, disruption of lifeline facilities, or other concerns.

Oil and Natural Gas

content from ToxipediaExtraction of oil and gas through hydraulic fracturing—commonly known as fracking—has become widespread, and natural gas has even been lauded as a source of greener energy for the future. An investigation of fracking impacts in Riverkeeper’s 2010 report included well blowouts and explosions, drinking and surface water contamination, improper wastewater discharge, stray gas migration and air pollution.89 A 2012 workshop convened by the Institute of Medicine Roundtable on Environmental Health Sciences, Research, and Medicine highlighted both occupational and community impacts:90

web of fracking pads

In areas where shale-drilling/hydraulic fracturing is heavy, a dense web of roads, pipelines and well pads turn continuous forests and grasslands into fragmented islands. Image from Simon Fraser University at Creative Commons

  • Chemicals that may pose exposure risks during oil and gas extraction include respirable crystalline silica, diesel particulate, volatile organic compounds (VOCs), hydrogen sulfide, acid gases, aldehydes, lead and other elements. The National Institute for Occupational Safety and Health determined that respirable crystalline silica presented an occupational exposure hazard likely greater than exposures to chemicals.
  • Noise
  • Increased heavy traffic
  • Social disruption

Studies have found that natural gas drilling operations may result in elevated endocrine-disrupting chemical activity in surface and ground water,91 with evidence that fracking operations can result in adverse reproductive health and developmental effects in humans.92

The hydraulic fracturing process—and especially the disposal of fracking wastewater by high-pressure injection into deep wells—has been linked to seismic activity and earthquakes, which can contribute to physical and mental harm to people.

The oil and gas industry is also a significant emitter of methane, a potent contributor to climate change, which has its own health impacts.93 A 2016 investigation concluded that total fossil fuel methane emissions (fossil fuel industry plus natural geological seepage) are 60 to 110 percent greater than previous estimates.94 This is a great concern, for methane is many times more potent as a greenhouse gas than carbon dioxide.

Burning natural gas produces negligible amounts of sulfur, mercury and particulates, but does produce nitrogen oxides—precursors to smog—but at lower levels than gasoline and diesel used for vehicles.95

Burning heating oil produces fewer carbon emissions than coal, but more than natural gas.96 Home heating oil is similar to diesel, but may have more sulfur content.97 As detailed above, diesel fuel produces more nitrogen oxides and particulate pollution than gasoline.

Nuclear Power

While nuclear-generated electricity is seen as part of the solution to electricity's contribution to climate change, nuclear power is not without its health impacts (information from the Canadian Association of Physicians for the Environment98 and supplemented as noted): 

Uranium Mining Impacts on Native American Communities

Uranium mining, which creates serious health and environmental problems, has disproportionately impacted indigenous people because much of the world’s uranium is located under indigenous land.99

Over several decades of uranium mining in the US, miners—and especially Native American miners—were not informed of known health impacts of the work, were not provided necessary ventilation or protective equipment, were systematically underpaid, and were often denied compensation for mining-related illnesses.100

Risks for lung cancer and other respiratory problems are nearly four times higher in Navajo miners than in nonminers. Communities around mines have a higher incidence of birth defects, and the Navajo Birth Cohort Study seeks to ascertain the causes.101 One of the study's findings: 27 percent of the participants have high levels of uranium in their urine, compared to 5 percent of the US population as a whole.102

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Uranium mining contaminates air, water and soil, which can impinge on nearby populations.
Crushing radioactive rock produces dust and leaves behind fine radioactive particles subject to wind and water dispersal. Radon gas, a potent lung carcinogen, is released continuously from the tailings in perpetuity. Drilling and blasting can disrupt and contaminate local aquifers. Water used to control dust and create slurries for uranium extraction becomes contaminated. The production of 1,000 tons of uranium fuel generates approximately 100,000 tons of radioactive tailings and nearly one million gallons of liquid waste containing heavy metals and arsenic in addition to radioactivity. These uranium tailings have contaminated rivers and lakes.103

Uranium miners experience higher rates of lung cancer, tuberculosis and other respiratory diseases.104

The fission process in reactors creates radioactive fission products.105 All functioning reactors routinely release radioactive material into the air and into the water used to cool them.

A 1995 pooled analysis of nuclear workers from the US, Canada and the UK found an increased risk for leukemia (excluding chronic lymphoid leukemia).106

In nuclear accidents, the radioactive isotopes released include I-131 and Cs-137. Human exposure to released I-131 comes mainly from consuming contaminated water, milk, or foods or by breathing contaminated dust particles in the air.107

Although it is very difficult to determine increases in cancer due to a specific event,108 exposure to radioactive iodine increases the risk of thyroid cancer many years later, especially for children and adolescents.109 Leukemia is also connected to nuclear power accidents: Studies after both the 1979 accident at the Three Mile Island reactor in the US and the 1986 accident at Chernobyl in Ukraine have shown elevated risks of leukemia among workers (Chernobyl) and the downwind community (Three Mile Island).110 Elevated rates of pre-menopausal breast cancer have also been noted in the community surrounding Chernobyl.111 Other documented health effects following Chernobyl include cataracts, cardiovascular disease, immunological changes, congenital malformations (birth defects), infant mortality, and mental health impacts.112  

apology from Tokyo Electric Power Co. leader

 

image from Dominic Alves at Creative Commons

Studies of health impacts of the 2011 Fukushima Daiichi nuclear power plant have cataloged disaster-related death caused by stress, exhaustion and worsening of pre-existing illnesses due to evacuation.113 Analyses of mortality following evacuation have concluded that the risks from evacuation were greater to nursing-home residents than the risks of radiation.114 Severe mental health problems and probable post-traumatic stress disorder have been documented among evacuees, including children.115

Other health impacts documented to date include a modest increase in perinatal mortality116 and an increased incidence of thyroid cancer in children,117 although it's too soon for full assessments of trends.

Transporting uranium and its waste carries with it the risk of accidents or spills, with further risk of air, water and soil contamination.

Nuclear waste storage is an ongoing problem, for as yet no safe way to dispose of spent fuel has been developed. Spent fuel remains radioactive for hundreds of thousands of years. “Geologic storage”—burying the waste deep underground—is being considered but carries the risk of potential contamination of air and water.

Wood

smoke from a furnace

image from Gerry at Creative Commons

Burning wood in fireplaces, wood stoves and outdoor wood furnaces generates particulate matter and releases toxicants including benzene, formaldehyde, acrolein and polycyclic aromatic hydrocarbons (PAHs). Health impacts from these toxicants include eye and throat irritation, respiratory problems (asthma, bronchitis, lung infections such as pneumonia and reduced lung function), cardiovascular disease and cancer. Children, teenagers, older adults, people with lung disease including asthma and COPD, or people with heart diseases are the most vulnerable.118

Burning biomass emits more carbon than fossil fuels per megawatt energy generated. Depending on the moisture content of the wood and the type of coal, burning wood produces roughly 150 percent the carbon dioxide of burning coal and up to 400 percent of the carbon dioxide of burning natural gas.119 Wood does not have the mining or refining emissions of these fuels, however, nor are spills a concern.

Renewable Energy

Renewable energy sources—including solar, wind, geothermal, hydroelectric and hydrokinetic (tide and wave) power—vastly reduce air pollution, water pollution and impacts on climate from emissions of carbon dioxide and methane.

Carbon dioxide equivalents of several fuels
Data are from the Union of Concerned Scientists. When ranges of estimates are available, the midpoint between high and low estimates is used;120 click to zoom.

Some renewable power sources have been used by humans for hundreds of years—dams, windmills and tide gates, for example. Recent new technologies and scale have brought new and expanded health impacts.

Benefits of Switching to Clean Energy121

  • Reduce millions of tons of carbon pollution
  • Reduce hundreds of thousands of tons of health-damaging particulate pollution and gases
  • Protect the most vulnerable
  • Reduce consumer electric bills
  • Increase participation of small businesses in energy market
  • For every $1 invested in clean power, US households will see $7 in health benefits
  • The US will see a $26-$46 billion health benefit
  • Annually, the US will have
    • 3,600 fewer premature deaths
    • 1,700 fewer heart attacks
    • 900,000 fewer asthma attacks
    • 300,000 fewer missed workdays and schooldays

Solar energy use, depending on the scale, can use land that otherwise might have been available for agriculture or other uses. Water is used in manufacturing solar panels, and concentrating solar thermal plants (CSP) technologies need water for cooling during electricity production.

However, most of the health impacts of solar power are from hazardous materials used in manufacturing PV solar panels. Workers can be exposed to chemicals including hydrochloric acid, sulfuric acid, nitric acid, hydrogen fluoride, 1,1,1-trichloroethane and acetone. Worker exposure to silicone dust is also a concern. Mining of rare earth elements can leave behind chemical and physical destruction that can greatly harm surrounding communities.122

Wind energy produced by industrial wind turbines (IWTs) can impact people who live or work nearby. Reported symptoms include decreased quality of life, annoyance, stress, sleep disturbance, headache, anxiety, depression and cognitive dysfunction. Some people report anger, grief or a sense of injustice. Suggested causes of symptoms include a combination of wind turbine noise, infrasound (low-frequency sound), dirty electricity, ground current and shadow flicker.123

Geothermal power plants use water from local sources. Open-loop systems emit carbon dioxide, ammonia, methane, boron and hydrogen sulfide, which eventually turns into sulfur dioxide and sulfuric acid which contributes to heart and lung disease. However, sulfur dioxide emissions from geothermal plants are approximately 30 times lower per megawatt-hour than from coal plants. Some geothermal plants also emit small amounts of mercury. Closed-loop systems emit almost nothing.

Hydrothermal plants are sited on geological “hot spots" which tend to have higher levels of earthquake risk. There is evidence that hydrothermal plants can lead to an even greater earthquake frequency.124

Hydroelectric power from dams can have tremendous impacts on land use and wildlife, but direct health impacts on humans are minimal,125 except for those who live downstream of a breached dam.

Hydrokinetic energy from tides and waves has no reported human health impacts at this time, although impacts on landscapes, wildlife and natural processes can be considerable.126

In sum, even though renewable energy sources have some negative health impacts, a switch to renewable and sustainable energy will reduce the production of air pollution from burning fossil fuels and will significantly impact public health and the economy.127

Power Transmission Lines

high voltage trasmission lines

image from Tim Anderson at Creative Commons

Low-frequency magnetic fields from power lines (EMFs) induce circulating currents within the human body. The strength of these currents depends on the intensity of the magnetic field. If sufficiently large, these currents can cause stimulation of nerves and muscles or affect other biological processes.128 The Bioinitiative Report 2012 reviewed studies in which "researchers report headaches, concentration difficulties and behavioral problems in children and adolescents and sleep disturbances, headaches and concentration problems in adults."129

More information about EMFs is on our Radiation Environment webpage.

Light Pollution

In addition to using electricity, which affects health as described above, light itself can have health impacts. The inappropriate or excessive use of artificial light—known as light pollution—includes these components:130

city lights

 

image from Mack Male at Creative Commons

  • Glare: excessive brightness that causes visual discomfort
  • Skyglow: brightening of the night sky over inhabited areas
  • Light trespass: light falling where it is not intended or wanted, or even needed
  • Clutter: bright, confusing and excessive groupings of light sources

A 2015 review of 85 studies concluded that exposure to artificial bright light during the nighttime suppresses melatonin secretion, increases sleep onset latency and increases alertness, thus delaying and possibly disrupting sleep. Nighttime light exposure may have negative effects on psychological, cardiovascular and/or metabolic functions.131

As described above with indoor lighting, blue light—shorter wavelengths of light—especially causes sleep disruption by disturbing melatonin secretion and causing circadian phase shifts, even if the light is not bright.132 White LED lamps, which emit more blue light than other types of lamps, are estimated to have five times greater impact on circadian sleep rhythms than conventional street lamps. In June 2016, the American Medical Association cautioned against blue wavelengths in outdoor lighting in their statement, "Community Guidance to Reduce the Harmful Human and Environmental Effects of High Intensity Street Lighting." The guidance recommends shielding all light fixtures and using only lighting with 3000K color temperature and below.133

Recreational Environments

content from ToxipediaCrumb rubber, made by shredding used vehicle tires, is the infill used on top of synthetic athletic fields as a cushioning agent between the green blades of plastic "grass." Shredded tires are also used on children's playgrounds. Crumb rubber's use is unregulated, and there is little consistency as to ingredients among manufacturers and batches. In June 2015, a Yale University/EHHI study determined that the recycled tire mixture contains as many as 96 different chemicals, including 12 carcinogens and 20 irritants. Toxic materials in crumb rubber include lead, styrene 1,3-butadiene, carbon black and carbon nanotubes.

crumb rubber with artificial turf

image from www.softsurfaces.co.uk at Creative Commons

Almost half of the chemicals identified in crumb rubber  lack any toxicity assessments. On February 12, 2016, the US Environmental Protection Agency, the Centers for Disease Control and Prevention/Agency for Toxic Substances and Disease Registry, and the US Consumer Product Safety Commission (CPSC) launched a multi-agency action plan to study key environmental human health questions about crumb rubber.134

Swimming pools may contain disinfection by-products, chemical constituents of personal care products—such as parabens and ultraviolet (UV) filters from sunscreens—and by-products from reactions of these chemicals with each other and with UV radiation. Exposure to some of these chemicals may lead to health risks.135

Waste

landfill

 

image from Alan Levine at Creative Commons

Waste disposal can impact human health. Residence near landfill sites has been related to raised incidence of low birth weight births and various congenital malformations (birth defects). Waste management workers have been shown to have increased incidence of accidents and musculoskeletal problems.136

Everything with an electric cord or battery eventually becomes electronic waste, known as e-waste. A 2013 estimate of roughly 40 million metric tons of e-waste produced globally each year hints at the scope of the problem. About 13 percent of that weight is recycled, mostly in developing countries. Informal recycling markets in China, India, Pakistan, Vietnam and the Philippines handle anywhere from 50 to 80 percent of this e-waste.137

E-waste often contains harmful substances, but additional toxicants can also be created during waste processing:138

  • Chemicals in the product itself: lead, mercury, cadmium and other metals; flame retardants and BPA
  • Chemicals created by substandard processes: dioxin formation during burning of halogenated plastics or use of smelting processes without suitable off-gas treatment; open-air burning used to retrieve valuable components also creates fine particulate matter air pollution
  • Reagents used in the recycling process: cyanide and other strong leaching acids, nitrogen oxides gas from leaching processes and mercury from amalgamation

boy melting ewaste

A boy winces at the smoke rising from the computer motherboards being melted over open fires in a recycling yard in Delhi; image from Greenpeace India at Creative Commons.

The 1989 Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and Their Disposal was created to regulate hazardous waste, but e-waste is a huge and still growing problem at disposal sites. Toxic contamination of air and water is common, and children are often among those trying to earn a living by breaking down e-waste to recover valuable materials.

Health impacts at unregulated or underregulated disposal sites and surrounding communities include cancer, pulmonary and cardiovascular disease, reproductive harm and neurological harm.139 Guiyu, China, is known as the largest e-waste recycling site in the world, and the city's residents exhibit substantial digestive, neurological, respiratory and bone problems. 80 percent of Guiyu's children experience respiratory ailments and are especially at risk of lead poisoning.140

Built Environment and Socioeconomic Status

CDC poster

graphic from the CDC; click to zoom

The built environment interacts with socioeconomic status: inequitable distributions of power, money and resources create inequitable access to built environments that support health. Poverty, age and mobility also make some populations more vulnerable to built environment-related disease than others. Youth, elderly, those with limited incomes and people with disabilities disproportionately experience poor built environments, such as those with high traffic volumes, noise and crime rates, or neighborhoods close to polluting industries. Indoor environments in low-income areas are more likely to expose residents to lead paint and mold. Exposure to more toxicants and fewer opportunities to engage in physical activity are a double whammy against low-income and disabled people.141

Built Environment and Mental Health

Exposures like noise, air pollution, overcrowding and a lack of access to nature can increase our physical and emotional stress. Conversely, integrating opportunities to interact with nature into the way we build our cities can have positive effects on our health, including allowing us to think more clearly and to reduce stress.142

With more time in a car comes more traffic congestion and delays, both linked to high blood pressure, more days in a hospital and decreased job performance.143 The association arises from the stress of unpredictability and loss of control experienced in traffic conditions. In this fashion, those with long daily commutes are at a higher risk of stress-related diseases.

Social Capital and Built Environment

Many factors contribute to a community’s sense of belonging, trust and reciprocity, otherwise known as social capital. Social capital is strengthened by vibrant social networks, a psychological sense of community and a community’s contact with nature. Features of the built environment can foster or inhibit a community’s social capital:144

  • Time spent alone in a car on in a private indoor space reduces social capital and increases isolation
  • Walkability and access to green spaces strengthen a community’s social capital, allowing people to meet, recognize and get to know neighbors
  • More public space provides opportunities to build social capital

Country and Community Priorities

Policymakers in different communities and countries may have very different priorities for the built environment. For example, developing countries may focus more than industrialized nations on providing basic infrastructure such as sanitation, housing and food. Both developing and industrialized nations may want to focus on reducing traffic crashes, air and water pollution and retaining farmland and forests. Solutions to issues may be different between countries based on community needs, priorities and resources.145

Built Environment Scale

Two scales of the built environment are typically considered: the regional and the local.

The regional scale considers major areas of population and how people get to and interact with places of employment and housing. Considerations include transportation to and from work, housing availability and cost, and school district and neighborhood quality. Healthier regional built environments focus on pedestrian-friendly design.

The local scale, or that of the neighborhood, also focuses on transit but more on household travel needs. The distance to frequent destinations, such as grocery stores, schools and recreation areas, and the ease of traveling by foot or bike both impact a person’s choices of active transportation. In disconnected neighborhoods, families often have to drive to access schools or recreational areas.146

Thriving in the Built Environment

This page presents dozens and dozens of ways that the built environment can harm our health, but it doesn't need to be so. Choices about materials in indoor environments can greatly improve the health impacts in the spaces where many of us spend most of our time. Some relatively minor adjustments can provide substantial health benefits.

Planning outdoor environments to minimize noise, reduce pollution and crime, promote physical activity and foster social connections is within our community control if we act together. There are many instances of communities that have reclaimed neighborhoods and reaped great economic and health benefits, making communities into places where people want to live, work and raise children.147 Individual choices regarding consumption and policymakers/lawmakers can drive much bigger changes. On a societal scale, choices about travel, energy sources, community design and economic structures have the potential to create more healthful built environments all around the world.


This page's content was created by Nancy Hepp and Lorelei Walker, PhD, and last revised in October 2016.

CHE invites our partners to submit corrections and clarifications to this page. Please include links to research to support your submissions through the comment form on our Contact page.

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