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Air quality and your health

Published September 19th, 2023

This summer, more than 120 million Americans were under air quality alerts as smoke from Canadian wildfires drifted into the United States.1 During this time, the CDC reported a 17% increase in asthma-related emergency room visits.2 Due to the changing climate, the frequency of these events is expected to rise, exposing people to poor air quality more often and for longer periods of time. Prolonged or frequent exposure to air pollution, from fires and other sources, can have negative effects on your health. In January of 2023, the U.S. Environmental Protection Agency (EPA) proposed strengthening the national air quality standard in an effort to improve protection against these effects.3

Air quality basics

Air quality is a measure of how clean or polluted the air is. Federal, state, and local agencies monitor air quality using the Air Quality Index (AQI) by measuring 5 major types of hazardous particle and chemical air pollutants including4:

Particle pollution or partical matter (PM)

  • The smallest particles, called PM2.5, include smoke from fires, vehicle exhaust, and factories.
  • Larger particles, called PM10, include dust from roads, construction sites, and mines.

Chemical pollution

  • Ground-level ozone
  • Carbon monoxide
  • Sulfur dioxide
  • Nitrogen dioxide

The AQI reports levels of air quality on a scale of 0-500 and is divided into 6 categories based on the level of health concern. These categories are color-coded by the level of threat, to make it easy for individuals to monitor their level of risk.

For context, the air quality index in New York City usually averages around 49 (Good), but in June 2023, when the smoke from Canadian wildfires seeped into the area, the index skyrocketed to 484 (Hazardous), temporarily making it the city with the worst air quality in the world.

Poor air quality can affect your health

Poor air quality is associated with a variety of health risks, most of which result from exposure to particulate pollution, like that found in smoke.5 These health risks are most dangerous for high-risk populations, including people with asthma, chronic obstructive pulmonary disease (COPD), cardiovascular disease, older adults, pregnant people, and young children.

Immediate/acute health risks

  • Lung and throat irritation
  • Shortness of breath
  • Wheezing or difficulty breathing
  • Rashes
  • Eye irritation

If you have been exposed to high levels of air pollution and are not feeling well, call your doctor or visit your local Urgent Care.

Long-term/chronic health risks

Prolonged or frequent exposure to air pollution can have serious, long-term, negative health effects. Studies have shown that chronic exposure to air pollution can increase risk for developing a variety of conditions.

Chronic respiratory illnesses

  • Air pollution increases the risk of developing chronic respiratory illnesses, including asthma, chronic bronchitis, COPD, and emphysema.6-9
  • The increased risk of developing asthma is particularly concerning in children exposed to poor air quality.10

Cancer risk

The World Health Organization recognizes air pollution as a human carcinogen (cancer causing agent), and studies have shown that poor air quality increases risk of a variety of cancers, including breast cancer, lung cancer and non-Hodgkins lymphoma.11

How does air pollution cause lung cancer?12

  • It was long hypothesized that air pollution could lead to lung cancer, but definitive evidence for how it promoted cancer was lacking until recently.
  • Scientists in the United Kingdom analyzed 32,957 lung tumors from non-smokers and found that increased PM5 air pollution led to a higher incidence of lung cancer.
  • Surprisingly, the reason was not because of increased mutations in lung tissue. Rather, they discovered that air pollution causes prolonged, low-level lung inflammation, which stimulates cells that were already mutated. This caused the cells to become cancerous.

Cardiovascular risk

  • Air pollution has shown to increase risk of cardiovascular diseases, including stroke and heart attacks.13,14

Pregnancy/prenatal risk

  • Air pollution has been associated with lower birth weights, increased risk of premature birth and increased risk of birth defects.15,16
  • Air pollution from automotive traffic has been shown to cause high blood-pressure in pregnant women.17

Dementia risk

  • There is increasing evidence that links air pollution with an elevated risk of cognitive impairment and dementia.18-20

Tips for protecting yourself in poor air quality

Monitor outdoor air quality in your area

Monitoring your air quality can help you to protect yourself from exposure to air pollution. Just like checking the weather before you head out for the day, it is becoming increasingly important to be aware of the air quality in your area. There are several ways to check your air quality. Each allows you to enter your location, get a real-time report about the air quality in your area, and manage your exposure if the air quality is poor.

  • The U.S. EPA’s air quality website or mobile app
  • Weather apps: The Weather Channel, AccuWeather, and the National Weather Service
  • Air Quality apps: AirCare, IQ Air
  • Portable and/or wearable air quality monitors available for home monitoring

When the air quality is poor, take measures to minimize your exposure

  • Stay indoors as much as possible. Limit outdoor time to less than 30 minutes.
  • Avoid exercising outdoors.
  • Keep your doors and windows closed.
  • Use air conditioning with HEPA filters.
  • If you must go outside, consider wearing a mask. Well-fitting N95 or KN95 masks are the best option.


  1. Yan, A. S., Mike Hayes,Holly. June 28, 2023 – Millions under air quality alerts in the US due to Canadian wildfire smoke. CNN (2023).
  2. McArdle, C. E. Asthma-Associated Emergency Department Visits During the Canadian Wildfire Smoke Episodes — United States, April– August 2023. MMWR Morb Mortal Wkly Rep 72, (2023)
  3. US EPA, O. EPA Proposes to Strengthen Air Quality Standards to Protect the Public from Harmful Effects of Soot. (2023).
  4. Air Quality | Tracking | NCEH | CDC. (2023). Fann, N. et al. Estimating the National Public Health Burden Associated with Exposure to Ambient PM2.5 and Ozone. Risk Analysis 32, 81–95 (2012).
  5. Altman, M. C. et al. Associations between outdoor air pollutants and non-viral asthma exacerbations and airway inflammatory responses in children and adolescents living in urban areas in the USA: a retrospective secondary analysis. Lancet Planet Health 7, e33–e44 (2023).
  6. Hooper, L. G. et al. Ambient Air Pollution and Chronic Bronchitis in a Cohort of U.S. Women. Environ Health Perspect 126, 027005 (2018).
  7. DeVries, R., Kriebel, D. & Sama, S. Outdoor Air Pollution and COPD-Related Emergency Department Visits, Hospital Admissions, and Mortality: A Meta-Analysis. COPD 14, 113–121 (2017).
  8. Wang, M. et al. Association Between Long-term Exposure to Ambient Air Pollution and Change in Quantitatively Assessed Emphysema and Lung Function. JAMA 322, 546–556 (2019).
  9. US EPA, O. The Links Between Air Pollution and Childhood Asthma. (2018).
  10. Air Pollution and Your Health. National Institute of Environmental Health Sciences
  11. Lung adenocarcinoma promotion by air pollutants | Nature.
  12. J, de B. et al. Ambient air pollution and cardiovascular diseases: An umbrella review of systematic reviews and meta-analyses. Journal of internal medicine 291, (2022).
  13. Sun, S. et al. Short-term exposure to air pollution and incidence of stroke in the Women’s Health Initiative. Environ Int 132, 105065 (2019).
  14. Rani, P. & Dhok, A. Effects of Pollution on Pregnancy and Infants. Cureus 15, e33906.
  15. Nieuwenhuijsen, M. J., Dadvand, P., Grellier, J., Martinez, D. & Vrijheid, M. Environmental risk factors of pregnancy outcomes: a summary of recent meta-analyses of epidemiological studies. Environmental Health 12, 6 (2013).
  16. National Toxicology Program (NTP). NTP Monograph on the Systematic Review of Traffic-related Air Pollution and Hypertensive Disorders of Pregnancy. (National Institute of Environmental Health Science, 2019). doi:10.22427/NTP-MGRAPH-7.
  17. Abolhasani, E. et al. Air Pollution and Incidence of Dementia: A Systematic Review and Meta-analysis. Neurology 100, e242–e254 (2023).
  18. Grande, G. et al. Association of Long-term Exposure to Air Pollution and Dementia Risk: The Role of Homocysteine, Methionine, and Cardiovascular Burden. Neurology 10.1212/WNL.0000000000207656 (2023) doi:10.1212/WNL.0000000000207656.
  19. Wu, J. et al. Air pollution as a risk factor for Cognitive Impairment no Dementia (CIND) and its progression to dementia: A longitudinal study. Environ Int 160, 107067 (2022).

About the Authors

Ross Keller, PhD

Research Director

Dr. Keller is focused on providing decision-grade information to cancer patients regarding the best treatments options. He has experience in genomics, cancer evolution, tumor modeling, and early-stage drug development.

Julie Nowicki, PhD

Health and Science Writer

Dr. Nowicki has a background in scientific research and education, with a focus on molecular genetics, and has extensive experience as a medical writer. At PHM, she writes a variety of scientific communications, including articles and educational materials that summarize complex medical information for patients.