Air Pollution and Your Health

1. Air Pollution and Your Health
● Health & Education
○ Environmental Health Topics
■ Environmental Agents
■ Acrylamide
■ Air Pollution and Your Health
■ Algal Blooms
■ Allergens & Irritants
■ Aloe Vera
■ Arsenic
■ Bisphenol A (BPA)
■ Cell Phone Radio Frequency Radiation
■ Climate Change
■ Cosmetics and Your Health
■ Dioxins
■ Electric & Magnetic Fields
■ Endocrine Disruptors
■ Essential Oils
■ Flame Retardants
■ Formaldehyde
■ Ginkgo
■ Hazardous Material/Waste
■ Hexavalent Chromium
■ Hydraulic Fracturing & Health
■ Indoor Air Quality
■ Lead
■ Mercury
■ Mold
■ Nanomaterials
■ Ozone
■ Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS)
■ Pesticides
■ Radon
■ Safe Water and Your Health
■ Soy Infant Formula
■ Styrene
■ Weather Extremes
Table of Contents
Introduction

2. Air pollution is a familiar environmental health hazard. We know what we’re looking
at when brown haze settles over a city, exhaust billows across a busy highway, or
a plume rises from a smokestack. Some air pollution is not seen, but its pungent
smell alerts you.
When the National Ambient Air Quality Standards were established in 1970, air
pollution was regarded primarily as a threat to respiratory health. Over the next
decades as air pollution research advanced, public health concern broadened to
include cardiovascular disease; diabetes mellitus; obesity; and reproductive,
neurological, and immune system disorders.
Air pollution exposure is associated with oxidative stress and inflammation in
human cells, which may lay a foundation for chronic diseases and cancer. In 2013,
the International Agency for Research on Cancer of the World Health Organization
(WHO) classified air pollution as a human carcinogen.
What Is Air Pollution?
Air pollution is a mix of hazardous substances from both human-made and natural
sources.
Vehicle emissions, fuel oils and natural gas to heat homes, by-products of
manufacturing and power generation, particularly coal-fueled power plants, and

3. fumes from chemical production are the primary sources of human-made air
pollution.
Nature releases hazardous substances into the air, such as smoke from wildfires,
which are often caused by people; ash and gases from volcanic eruptions; and
gases, like methane, which are emitted from decomposing organic matter in soils.
Traffic-Related Air Pollution (TRAP), from motor vehicle emissions, may be the
most recognizable form of air pollution. It contains most of the elements of
human-made air pollution: ground-level ozone, various forms of carbon, nitrogen
oxides, sulfur oxides, volatile organic compounds, polycyclic aromatic
hydrocarbons, and fine particulate matter.
Ozone, an atmospheric gas, is often called smog when at ground level. It is
created when pollutants emitted by cars, power plants, industrial boilers, refineries,
and other sources chemically react in the presence of sunlight.
Noxious gases, which include carbon dioxide, carbon monoxide, nitrogen oxides
(NOx), and sulfur oxides (SOx), are components of motor vehicle emissions and
byproducts of industrial processes.
Particulate matter (PM) is composed of chemicals such as sulfates, nitrates,
carbon, or mineral dusts. Vehicle and industrial emissions from fossil fuel
combustion, cigarette smoke, and burning organic matter, such as wildfires, all
contain PM.
A subset of PM, fine particulate matter (PM 2.5) is 30 times thinner than a human
hair. It can be inhaled deeply into lung tissue and contribute to serious health
problems. PM 2.5 accounts for most health effects due to air pollution in the U.S.

4. Volatile organic compounds (VOC) vaporize at or near room
temperature—hence, the designation volatile. They are called organic because
they contain carbon. VOCs are given off by paints, cleaning supplies, pesticides,
some furnishings, and even craft materials like glue. Gasoline and natural gas are
major sources of VOCs, which are released during combustion.
Polycyclic aromatic hydrocarbons (PAH) are organic compounds containing
carbon and hydrogen. Of more than 100 PAHs known to be widespread in the
environment, 15 are listed in the Report on Carcinogens. In addition to
combustion, many industrial processes, such as iron, steel, and rubber product
manufacturing, as well as power generation, also produce PAHs as a by-product.
PAHs are also found in particulate matter.
Fact Sheets
4 pages
(441KB)
Partnerships for Environmental Public Health (PEPH)
What Is NIEHS Doing?
Over its 50-plus year history, NIEHS has been a leader in air pollution research. In
1993, NIEHS researchers published the landmark Six Cities Study, which
established an association between fine particulate matter and mortality. The

5. institute continues to fund and conduct research into how air pollution affects
health and the population groups who are most affected.
How does air pollution affect our health?
Respiratory Disease
● Air pollution can affect lung development and is implicated in the
development of emphysema, asthma, and other respiratory diseases, such
as chronic obstructive pulmonary disease (COPD).
● PM and nitrogen oxide are linked to chronic bronchitis.
● In 2020, a major public health challenge was confluence of the COVID-19
pandemic and wildfires across the western U.S. Building on a
well-established connection between air pollution and respiratory-tract
infections, a study linked wildfire smoke with additional COVID-19 cases
and deaths.
Cardiovascular Disease
● Fine particulate matter can impair blood vessel function and speed up
calcification in arteries.
● NIEHS researchers established links between short-term daily exposure by
post-menopausal women to nitrogen oxides and increased risk of
hemorrhagic stroke.
● For a cross-section of older Americans, exposure to TRAP can result in
lowered levels of high-density lipoprotein, sometimes called good
cholesterol, increasing their risk for cardiovascular disease.
● According to a National Toxicology Program (NTP) report, TRAP exposure
also increases a pregnant woman’s risk for dangerous changes in blood
pressure, known as hypertensive disorders, which are a leading cause of
pre-term birth, low birth weight, and maternal and fetal illness and death.

6. Cancer
● A large study of more than 57,000 women found living near major roadways
may increase a woman’s risk for breast cancer.
● The NIEHS Sister Study found other airborne toxic substances, especially
methylene chloride, which is used in aerosol products and paint removers,
are also associated with increased risk of breast cancer.
● Occupational exposure to benzene, an industrial chemical and component
of gasoline, can cause leukemia and is associated with non-Hodgkin’s
Lymphoma.
● A long-term study, 2000-2016, found an association between lung cancer
incidence and increased reliance on coal for energy generation.
Whom does air pollution affect the most?
Air pollution affects everyone’s health, but certain groups may be harmed more.
Almost 9 out of 10 people who live in urban areas worldwide are affected by air
pollution.
Children
The NIEHS-funded Children’s Health Study at the University of Southern California
is one of the largest studies of the long-term effects of air pollution on children’s
respiratory health. Among its findings:
● Higher air pollution levels increase short-term respiratory infections, which
lead to more school absences.
● Children who play several outdoor sports and live in high ozone
communities are more likely to develop asthma.
● Children living near busy roads are at increased risk for asthma.

7. ● Children with asthma who were exposed to high levels of air pollutants were
more likely to develop bronchitis symptoms.
● Living in communities with higher pollution levels can cause lung damage.
Other studies on women and children
● NIEHS-funded researchers from the University of California, Davis,
Environmental Health Sciences Center are conducting the Bio-Specimen
and Fire Effects (B-SAFE) Study. This ongoing project seeks to discover if
and how recent wildfires and their smoke affected pregnant women and
their babies. Begun in 2017, study participants are pregnant women who
were living in Northern California when the 2018, 2019, or 2020 wildfires
occurred there.
● Breathing PM 2.5, even at relatively low levels, may alter the size of a
child's developing brain, which may ultimately increase the risk for cognitive
and emotional problems later in adolescence.
● Prenatal exposure to PAHs was associated with brain development effects,
slower processing speed, attention-deficit and hyperactivity disorder
(ADHD) symptoms, and other neurobehavioral problems in urban youth.
● In New York City, prenatal exposure to air pollution may play a role in
childhood ADHD-related behavior problems.

8. ● Prenatal exposure to particulate matter was associated with low birth
weight.
● Women exposed to high levels of fine particulate matter during pregnancy,
particularly in the third trimester, may have up to twice the risk of having a
child with autism.
● Second and third trimester exposure to PM 2.5 might increase the chance
of those children having high blood pressure in early life.
● In California’s agricultural San Joaquin Valley, women who were exposed to
high levels of carbon monoxide, nitrogen oxide, or nitrogen dioxide during
their first 8 weeks of pregnancy were more likely to have a baby with neural
tube defects.
● In Marietta, Ohio, home to a ferromanganese refinery, manganese
concentrations in blood and hair, a biomarker of air pollution exposure, were
associated with lower child IQ scores.
Older adults
● Alzheimer’s disease and related dementias are a public health challenge for
aging populations. NIEHS-funded researchers at the University of
Washington identified a link between air pollution and dementias. This
well-conducted study adds considerable evidence that ambient air fine
particles increase risk of dementias.
● Air pollution was linked to a greater chance of developing several
neurological disorders, including Parkinson's disease, Alzheimer's disease,
and other dementias. Hospital admissions data from 63 million older adults
in the U.S., obtained over 17 years (2000-2016), was analyzed along with
estimated PM 2.5 concentrations by zip code to conduct the study.
● In older adults, long-term exposure to TRAP may significantly hasten
physical disabilities. The risk is more pronounced among racial minorities
and lower-income people.

9. ● PM 2.5 air pollution is also associated with accelerated memory problems
and Alzheimer’s-like brain declines, which was seen among women 65
years of age and older. Conversely, a multi-year study published in 2022
shows improved air quality is associated with lower risk of dementia in older
women. The researchers also stated this decline in dementia risk was
equivalent to taking nearly 2 1/2 years off the age of the women studied.
● Nutrients may counter some harmful effects from air pollution. A 2020 study
found omega-3 fatty acids, obtained by eating certain fish, may protect
against PM 2.5-associated brain shrinkage in older women.
Rural dwellers
● An NIEHS-funded study found that concentrations of PM 2.5 in rural
Washington State were comparable to urban Seattle. In this study, as
regional PM 2.5 increased, there were increased asthma symptoms, such
as limitation of activities, more wheezing, and more nighttime waking, in
rural children.
● In the rural U.S., large-scale animal feeding operations might compromise
regional air quality through emission of pollutants, such as ammonia gas. A
study found acute lung function problems in children with asthma in such
areas.
Different genes
Your genes play a role in respiratory health. NIEHS-funded research discovered
that people with specific gene variants, which made them more likely to have lung
inflammation, had a greater chance of suffering from asthma if they lived close to
major roadways.
NIEHS and community involvement

10. Breathing dust from mine tailings, created by active and abandoned mining
operations, affects lung function. NIEHS grant recipients address such health
hazards in disadvantaged communities, such as Native American people in the
West, through culturally relevant health communication.
NIEHS also helps residents of Imperial County, California track air pollution
through a network of 40 community-run monitors. In this county, long-term
improvements in air quality were associated with significant lung-function
improvement in children.
Join an asthma study!
The goal of the Natural History of Asthma with Longitudinal Environmental Sampling
(NHALES) study is to help scientists understand how bacteria and other factors in the
environment affect people who have moderate to severe asthma.
Who can participate?
● Moderate to severe asthmatics.
● Males and females, aged 18-60.
● Females should not be pregnant or breastfeeding at the start of the study, but may still
participate if they become pregnant during the study.
● Nonsmokers who are also not around significant amounts of secondhand smoke.
● No history of chronic obstructive pulmonary disease, emphysema, cystic fibrosis (CF),
pulmonary fibrosis, non-CF bronchiectasis, sarcoidosis, unstable angina, or pulmonary
hypertension.
● Not allergic to methacholine.
● Able to provide your own transportation to clinic visits on the NIEHS campus in North
Carolina.
For more information about this study:
NHALES: Asthma Study
Tel 855-MYNIEHS (855-696-4347)
nhales@mail.nih.gov

11. Community-level tactics can help reduce exposure to TRAP:
● Using high-efficiency particulate air (HEPA) filtration.
● Building land-use buffers and vegetation barriers.
● Improving urban design with gardens, parks, and street-side trees.
● Creating active-travel options, such as bicycling and walking paths.
Why improving air quality matters
● Air pollution and birth outcomes are linked as global public health concerns.
Researchers analyzed indoor and outdoor air pollution data from all
inhabited continents along with key pregnancy outcomes. Their findings
indicate efforts to reduce PM2.5 exposure could lead to significant
reductions in the number of low-birth weight and pre-term birth infants
worldwide. Air pollution reduction would be especially beneficial for children
born in low- and middle-income countries.
● Among children in Southern California, decreases in ambient nitrogen
dioxide and PM 2.5 were associated with fewer cases of asthma.
● An NIEHS-funded study found that a mixture of several B vitamins may
protect DNA from changes attributable to PM 2.5 air pollution.
● Bronchitis symptoms declined as pollution levels dropped in the Los
Angeles region.
● Improving air quality may improve cognitive function and reduce dementia
risk, according to studies supported in part by NIH and the Alzheimer's
Association.
● When fossil-fuel power plants close, nearby air pollution is reduced. A study
found the incidence of preterm births went down within 5 kilometers of
retired coal and oil-powered plant locations.
Further Reading

12. Stories from the Environmental Factor (NIEHS newsletter)
● Interventions Needed to Slow Climate-driven Air Pollution, Researchers
Note (March 2022)
● Air Pollution and Forever Chemicals Continue to Pose Health Risks (March
2022)
● Links Between Air Pollution, Diet, and Heart Health Focus of Webinar
(December 2021)
● Fine Particulate Air Pollution Associated With Higher Dementia Risk
(September 2021)
● Better Air Quality May Lower Dementia Risk Among Older Women (August
2021)
● Indoor Air a Neglected Source of Chemical, Particulate Exposures (May
2021)
● Wildfire Severity Increases, Experts Call for Coordinated Federal Response
(May 2021)
● Air Quality Monitoring Innovations Merit Small Business Recognition
(February 2021)
● Climate Change Worsens Air Pollution, Extreme Weather, Expert Says (July
2020)
● Health Disparities in Congressional Spotlight (June 2020)
● COVID-19 Research Grants Get Rapid NIEHS Funding (May 2020)
● Pregnancy Hypertension Risk Increased by Traffic-related Air Pollution
(January 2020)
● NIH Researchers Tackle Questions on Air Pollution and Pregnancy
(September 2019)
● Nonsmokers Can Get Emphysema from Air Pollution, Study Finds
(September 2019)
● India and NIEHS Partner to Advance Air Pollution Research (August 2019)
● Los Angeles Youth Take on Air Monitoring (February 2019)

13. Podcasts
● Air Pollution and Your Heart is about the role air pollution plays in heart
disease.
● Air Quality Monitoring for Citizen Science explores the potential and
limitations of air quality monitors and offers strategies for citizen scientists
who want to use monitors.
● When Wildfires Hit Close to Home is about NIEHS-funded research on the
complexity of urban wildfires and how they may affect human health.
● Wildfire Smoke and Children's Health
Additional Resources
● AirNow, a tool developed in partnership by several government agencies,
allows you to monitor air quality in real time anywhere in the U.S. Simply
enter your zip code as indicated on the website.
● EPA's Air Sensor Toolbox provides information on the operation and use of
air-sensor monitoring systems for technology developers, air-quality
managers, citizen scientists, and the public.
● How Smoke From Fires Can Affect Your Health – To limit your exposure to
smoke, the EPA offers steps you can take to protect yourself.
● Smoke-ready Toolbox for Wildfires is a compendium of resources from the
EPA to help educate you about the risks of smoke exposure and actions
that protect your health.
● THE (Trade, Health, Environment) Impact Project brings together
researchers and community groups to find solutions for communities
affected by trade-related pollution, such as ports and roadways with
trucking.
● Wildfire Smoke Collection – The journal Environmental Health Perspectives
has published high-impact papers and reviews exploring exposure and
resulting health effects related to wildfires.

14. Related Health Topics
● Asthma
● Exposure Science
● Gene and Environment Interaction
● Lung Diseases
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