The health effects of tiny, invisible particles of air pollution can penetrate deep into our lungs, bloodstream and body. According to the World Health Organization, these pollutants are responsible for about one-third of deaths from stroke, chronic respiratory disease and lung cancer, and a quarter of deaths from heart disease.
The combined effects of ambient and household air pollution cause 6.7 million premature deaths each year (World Health Organization, 2022). It is estimated that ambient (outdoor) air pollution caused 4.2 million premature deaths worldwide in 2019.

Air pollution is a global problem due to its wide scope and far-reaching impact, and without proactive intervention, deaths from outdoor air pollution are expected to increase by more than 50% by 2050.
The World Health Organization celebrates International Clean Air Day on September 7 every year for blue skies, and the theme for 2023 is “Creating Clean Air Together”, which highlights the need for “strengthened alliances, increased investment and shared responsibilities given the cross-border nature of air, To overcome air pollution” To tackle pollution, all stakeholders must take responsibility for protecting the Earth’s atmosphere and ensuring healthy air for all, they said.
How does air pollution affect our health?
The National Institute of Environmental Health Sciences (NIEHS) has been a leader in air pollution research for more than 50 years and continues to fund and conduct research on how air pollution affects the health and populations most affected. Some of the data provided in this regard related to diseases related to this issue are:
- Respiratory Diseases: Because air pollution affects lung development, it has been linked to the development of emphysema, asthma, and other respiratory diseases such as chronic obstructive pulmonary disease (COPD); PM and nitrogen oxides have been linked to chronic bronchitis.
- Cardiovascular diseases: Fine particulate matter affects blood vessel function and accelerates arterial calcification. Researchers at the NIEHS Research Institute found a link between short-term daily exposure to nitrogen oxides and an increased risk of hemorrhagic stroke in postmenopausal women.
In a representative sample of older Americans, exposure to TRAP contamination results in lower levels of high-density lipoprotein (sometimes called good cholesterol), which increases the risk of cardiovascular disease.

According to a report from the National Toxicology Program (NTP), exposure to TRAP contamination also increases a pregnant woman’s risk of dangerous changes in blood pressure, known as hypertensive disease, which is premature birth, low birth weight, and illness and death for the mother and baby.
- cancer: A large study of more than 57,000 women by the NIEHS Research Institute found that living near major roads increases a woman’s risk of breast cancer. Other airborne toxins, particularly methylene chloride used in aerosol products and paint strippers, are also linked to an increased risk of breast cancer, the study found.
Occupational exposure to benzene, an industrial chemical and component of gasoline, can cause leukemia and has been linked to non-Hodgkin lymphoma. A long-term study from 2000 to 2016 found a link between lung cancer incidence and greater reliance on coal for energy production.
Who is most affected by air pollution?
The USC Children’s Health Study, funded by NIEHS, is one of the largest studies of the long-term effects of air pollution on children’s respiratory health. Its findings include:

- Higher levels of air pollution can increase respiratory infections in the short term, leading to more school absences.
- Children who play a variety of outdoor sports and live in communities with high ozone are more likely to develop asthma.
- Children who live near busy roads are at higher risk of developing asthma.
- Children with asthma who are exposed to high levels of air pollutants are more likely to develop symptoms of bronchitis.
- Living in a neighborhood with higher levels of pollution can lead to lung damage.
Other studies on women and children
Researchers at the UC Davis Center for Environmental Health Sciences, funded by the NIEHS Institute, are conducting the Biological Specimens and Fire Effects (B-SAFE) study. This ongoing project aims to understand whether and how recent wildfires and their smoke are affecting pregnant women and their babies. The study, which began in 2017, included pregnant women living in Northern California at the time of wildfires in 2018, 2019 or 2020.
Inhaling PM 2.5, even at relatively low concentrations, can alter the size of children’s developing brains, ultimately increasing the risk of cognitive and emotional problems in late adolescence.
Prenatal exposure to PAHs can affect brain development, slow processing speed, attention deficit hyperactivity disorder (ADHD) symptoms, and other neurobehavioral problems in urban adolescents. In New York City, prenatal exposure to air pollution may lead to ADHD-related behavioral problems in children.

Prenatal exposure to particulate matter is associated with low birth weight. Women who are exposed to high levels of particulate matter during pregnancy, especially in the third trimester, may be at twice the risk of giving birth to a child with autism. Exposure to MP 2.5 during the second and third trimester may increase a child’s risk of developing hypertension in the first years of life.
In California’s agricultural San Joaquin Valley, women who were exposed to high levels of carbon monoxide, nitric oxide, or nitrogen dioxide in the first eight weeks of pregnancy were more likely to give birth to babies with neural tube defects.
In Marietta, Ohio, home to an iron and manganese refinery, blood and hair manganese concentrations (biomarkers of air pollution exposure) were associated with lower IQs in children.

Elderly research
Air pollution has been linked to a higher likelihood of developing a variety of neurological diseases, including Parkinson’s disease, Alzheimer’s disease and other types of dementia. To conduct this study, we analyzed hospital admission data for 63 million older Americans obtained over a 17-year period (2000 to 2016) and estimated MP 2.5 concentrations by code.
Improved air quality can improve cognitive function and reduce the risk of dementia, according to research supported in part by the National Institutes of Health (NIH) and the Alzheimer’s Association. In older adults, long-term exposure to TRAP contamination can significantly accelerate physical disability. Minorities and low-income people are at increased risk.
MP 2.5 Air pollution has also been linked to accelerated memory problems and Alzheimer’s-like brain decline, both of which have been observed in women aged 65 and older. Nutrients can counteract some of the harmful effects of air pollution. A 2020 study found that omega-3 fatty acids obtained by eating some fish may prevent MP 2.5-related brain shrinkage in older women.
Genes play an important role in respiratory health. Research funded by the NIEHS Research Institute found that people with specific genetic variants that make them more susceptible to lung inflammation are more likely to develop asthma if they live near major roads.
Pollutants according to the World Health Organization
The main pollutants are:
Particulate matter is a common surrogate indicator of air pollution. There is reliable scientific data demonstrating the health effects of exposure to this pollutant. The main components of particulate matter are sulfates, nitrates, ammonia, sodium chloride, black carbon, mineral dust and water.
- Carbon monoxide (CO)
Carbon monoxide is a colorless, odorless and tasteless toxic gas produced when carbon fuels such as wood, petroleum, charcoal, natural gas and kerosene are burned incompletely.
Ground-level ozone (not to be confused with the ozone layer in the upper atmosphere) is one of the main components of photochemical smog and is formed when sunlight reacts with the gas.
- Nitrogen dioxide (NO2)
NO2 is a gas commonly released when fuel is burned in the transportation and industrial sectors.
SO2 is a colorless gas with a pungent odor. It is produced by burning fossil fuels (coal and oil) and smelting sulfur-containing ores.