Asthma Capitals: Risk Factors and Indicators That Can Worsen Asthma or Influence Asthma Rates

Socioeconomic status plays a major role in the development of asthma and a person’s ability to manage it. People living below 100% of the Federal Poverty Level (FPL) are more likely to have asthma than people living at any percentage above the poverty level.¹

Numerous studies have explored and confirmed the link between poverty and poor asthma outcomes. For example, living in poverty directly affects:

• Housing quality and increased exposure to indoor asthma triggers
• Physical environment and increased exposure to outdoor asthma triggers
• Ability to pay for asthma care due to competing priorities and basic needs
• Access to quality asthma care due to suboptimal health care coverage.

Many cities in our report have poverty as a top risk factor. Good asthma management can be difficult when families are worried about paying for housing, clothing, utilities, and food. The cost of care may affect the decision to seek medical care. A lack of reliable transportation and paid sick leave may influence a person’s ability to attend regular health care appointments.

These cities have the highest rates of poverty^†:

† For each city included in the 2025 Asthma Capitals, AAFA obtained the poverty rate for its respective county. The estimates range from 7.2% to 26.9%. Download image of Figure 1 table

Insurance status is one of the strongest predictors of consistent access to asthma care. People without insurance, or with limited coverage, face steep costs for routine office visits, emergency care, and medicines. Even people with insurance often face high deductibles and copays.

However, insurance itself can also be costly. These costs may vary depending on employment status and whether the job offers health insurance as a benefit and pays any of the costs. Other options include marketplace health insurance and government-sponsored insurance, like Medicare or Medicaid. Some states have expanded health insurance options for their residents while others have not. Racial and ethnic minority populations disproportionately experience barriers to health insurance, contributing to disparities in health care.

These cities have the highest number of uninsured residents^†:

† For each city included in the 2025 Asthma Capitals, AAFA obtained the uninsured rate for its respective county. The estimates range from 3.1% to 30.2%. Download image of Figure 2 table

Asthma medications can be expensive, particularly newer, targeted options. People with asthma may choose to ration their inhalers, delay refills, or skip doses to save money.³ In some cases, families must choose between asthma medicine and other household expenses. These financial pressures lead to worse control, higher risks of asthma attacks, and greater reliance on emergency care.

Recent changes to government insurance options like Medicaid may put people in this program at risk of losing coverage.

Medicaid offers a safety net for many people with asthma whose household income falls below certain government-set limits. Nearly half of all children with asthma get their health insurance through Medicaid, and adults on Medicaid are 2 times more likely to have asthma than adults with private insurance. Federal legislation passed in July 2025 will create new barriers to qualify for Medicaid and this may take that lifeline away for some people, or place additional burdens on these individuals to keep their coverage.

Nonpartisan projections indicate the Medicaid cuts imposed by the new law may result in around 16 million people losing health insurance coverage by 2034,⁴ including nearly 2 million people with asthma. Experts also project other consequences:

• Rural hospitals will close faster.⁵ Rural hospitals provide access to care and treatment for many people with asthma.
• With fewer hospitals/clinicians as a fall out from these cuts, even people on private insurance will experience adverse impacts to their care, including loss of access to treatment and a potential rise in emergency room visits.⁶

Medicaid cuts passed in the recent federal bill are expected to go into effect toward the end of 2026. Experts warn that these cuts will reverse gains in asthma care made in recent years.

Effective asthma management begins with access to the right providers. Many people with asthma rely on primary care providers, who diagnose the condition, prescribe medicines, and offer follow-up management. But for many people—especially those with severe or uncontrolled asthma—specialist care can make a significant difference. Allergists and pulmonologists can provide advanced diagnostic testing, offer advanced therapies, and create individualized management plans.

Yet access to specialists varies dramatically. In rural areas, people may have to travel for hours to see a specialist. Even in urban centers, shortages of specialists serving low-income neighborhoods can leave families without nearby options. Long wait times are common, sometimes stretching weeks or months.

These cities have the fewest asthma specialists per asthma patient^†:

† For each city included in the 2025 Asthma Capitals, AAFA obtained data on specialists per 10,000 asthma patients. Download image of Figure 3 table

People managing asthma and allergies can search for specialists in their area using the Find an Allergist tool from the American College of Allergy, Asthma & Immunology (ACAAI): acaai.org/find-an-allergist

Poor air quality can negatively affect everyone’s health. Research shows that air pollution can make asthma worse and trigger asthma symptoms.⁷ It also causes increased rates of emergency room visits, hospital admissions, and school absenteeism related to asthma. Air pollution includes gases, smoke from fires, volcanic ash, dust particles, emissions from transportation, and other substances that can harm the lungs.

Major air pollutants include:

• Harmful gases (ground-level ozone, carbon monoxide, sulfur dioxide, nitrogen dioxide)
• Particle pollution (also called particulate matter or soot pollution, reported by size: PM_2.5 and PM₁₀)

Ground-level ozone, a gas, is one of the most common air pollutants. Ozone contributes to what we typically experience as smog or haze. Ozone triggers asthma because it is irritating to the lungs and airways. Other gases can also trigger asthma.

Small particles in the air found in haze, smoke, and airborne dust can pass through your nose or mouth and get into your lungs. People with asthma are at greater risk from breathing in small particles. PM_2.5 pollutants are the most dangerous because they can get deep into the airways.⁸

Nearly half of the U.S. population lives in areas with unhealthy levels of ozone or particle pollution.⁹

These cities all received an F rating from the American Lung Association’s 2025 State of the Air Report for high ozone days and particle pollution^†:

† For each city included in the 2025 Asthma Capitals report, AAFA obtained the grades for high ozone days and particle pollution for the respective county. Grades were averaged to produce an overall grade, ranging from A to F. Download image of Figure 4 table

Housing Quality and Indoor Air Pollution

Indoor air quality is just as important as outdoor air quality. We spend about 90% of our time indoors, whether at school, home, or in the workplace.¹⁰ Indoor air can be up to 5 times more polluted than outdoor air. Buildings can trap harmful air pollution and other asthma triggers inside. Reducing asthma triggers in homes, schools, and workplaces is an important part of asthma management.

The following can negatively affect indoor air quality:

• Allergens, such as dust mites, animal dander, cockroaches, and mold
• Scents and fragrances from candles, scent diffusers, cleaning products, and personal hygiene products
• Chemicals and volatile organic compounds (VOCs) from building materials, cleaning products, and new furniture
• Burning fuels and wood (from cooking food or heating the indoor space)
• Emissions from vehicles, gas-powered generators, and other machinery
• Outdoor air pollution that enters the building (like from wildfire smoke)
• High levels of humidity that encourage mold growth and dust mites

Due to limited data on the MSA level, AAFA’s Asthma Capitals report does not rank cities based on indoor air quality (IAQ) or housing quality as a risk factor for asthma. But this is a critical area to address in housing policy, building maintenance, school environmental policies, and workplace accommodations.

In the U.S., about 1 in 4 adults and 1 in 5 children have seasonal allergies such as pollen allergy.^11,12 Pollen is a common allergen that can cause allergic asthma (asthma triggered by allergens).

That number could rise in the coming years due to climate change.¹³ Many people have been experiencing worsening pollen allergy symptoms over the years.

Pollen allergy seasons start earlier and end later in the year than they did previously.¹⁴ Research shows that from 1990-2018, pollen seasons start 20 days earlier and last 10 days longer.¹⁵ With warmer, longer seasons, allergy-causing plants can move into new areas. Ragweed, for example, is migrating northward due to climate change.

These cities have the highest pollen scores^†:

† For each city included in the 2025 Asthma Capitals, AAFA obtained daily pollen counts for each growth form (tree, grass, and weed) for the most recent calendar year (2024). Data were obtained from Pollen Sense, LLC Automated Particulate Sensors (APS). These sensors automatically image particulate matter collected from ambient air and use a neural network algorithm to identify individual pollen species and calculate daily pollen counts. Using these daily pollen counts, AAFA calculated the number of days each MSA had within the “high” or “very high” levels for each growth form, as determined by existing risk scales for each type. “Very high” days had a higher weight than “high” days for the final calculation of pollen scores. Download image of Figure 5 table

Tobacco smoke and e-cigarette aerosol can be especially harmful to people who have asthma.

About 1 in 5 adults with asthma smoke tobacco products.¹⁶ Children who live with smokers have more frequent asthma attacks. More than 40% of children who go to the emergency department for asthma live with smokers.¹⁷

According to the CDC, smoking is the leading cause of preventable death in the U.S.¹⁸ Smoking is not only harmful to the person doing the smoking but also to people nearby who inhale secondhand smoke or come into contact with thirdhand smoke. People with asthma are at greater risk of harm from tobacco products. Many chemicals, gases, and small particles in secondhand and thirdhand smoke can irritate the lungs and airways, causing additional inflammation and swelling.

Secondhand smoke—also known as environmental tobacco smoke (ETS)—refers to smoke that is released in the air when a smoker exhales, as well as smoke released from a burning cigarette, cigar, or pipe. Secondhand aerosols are also released by electronic smoking devices (e-cigarettes, hookahs, vapes).

Thirdhand smoke is residue from tobacco smoke. When a nicotine product is smoked, chemicals in the smoke stick to surfaces and dust for months after the smoke is gone. The chemicals in the residue then react to other pollutants in the air, like ozone, to create harmful particles you can easily inhale or ingest.¹⁹

Tobacco smoke and aerosols (including secondhand and thirdhand smoke) are unhealthy for everyone. There is no safe level of exposure to secondhand or thirdhand smoke. But many non-smokers are exposed to ETS in public places, homes, vehicles, and workplaces.

These cities do the least to protect their residents and visitors from tobacco smoke and have fewer smoke-free laws^†, comparatively:

† For each city included in the 2025 Asthma Capitals, AAFA obtained data on whether there was a 100% smoking ban for cars with minors, non-hospitality workplaces, restaurants, bars, and multi-unit housing. Download image of Figure 6 table

Prohibiting smoking in indoor spaces protects nonsmokers (including children) from ETS. Many state and local jurisdictions have passed laws that ban smoking in some places. These smoke-free zones may include workplaces, restaurants, hotels, parks, public housing, and transit systems. Research your state or county to see what the laws are in your area.

Both control medicines (sometimes called “controllers”) and quick-relief medicines (sometimes called “rescue inhalers”) may be necessary for optimal asthma management.

Quick-relief medicines help relieve asthma symptoms as they happen. These medicines act fast to relax the constricting smooth muscles around the airways. This allows the airways to open up so air can flow through them.

Frequent use of a quick-relief medicine (like albuterol) may indicate a higher number of asthma episodes and lack of asthma control.

Quick-relief medicine use is highest in these cities^†:

† For each city included in the 2025 Asthma Capitals, AAFA obtained the total number of quick-relief medicine prescriptions for the respective census-designated metropolitan statistical area, or MSA, from 2024. Analysis included estimating the prescription rate per patient prevalence. Download image of Figure 7 table

Control, or controller, medicines help prevent and control asthma symptoms. There are several kinds of asthma control medicines, including inhaled corticosteroids (ICS) and biologics. Asthma control medicines are prescribed for persistent cases of asthma. A high number of these prescriptions may indicate that a city’s residents have more severe or uncontrolled cases of asthma.

Asthma control medicine use is highest in these cities^†:

† For each city included in the 2025 Asthma Capitals, AAFA obtained the total number of controller medicine prescriptions for the respective census-designated metropolitan statistical area, or MSA, from 2024. Analysis included estimating the prescription rate per patient prevalence. Download image of Figure 8 table

One type of control medicine for asthma, called biologics, are available for people with moderate-to-severe asthma. These medicines are not for everyone, but for certain people, they can make a meaningful difference in reducing symptoms, improving quality of life, and lowering the need for oral steroids.

Biologic drugs (or biologics) are antibodies (proteins) that are designed to block specific molecules in the human body. Asthma biologics work by disrupting cells or blocking specific molecules that trigger inflammation. Most biologics can be taken at home or given in a doctor’s office every 1 to 8 weeks. They are given through an injection (shot) or intravenously (through an IV).

As of 2025, there are 6 biologics approved by the FDA for asthma—Xolair, Nucala, Fasenra, Cinqair, Dupixent, and Tezspire. Additional drugs are under development and may be available soon.

1. Centers for Disease Control and Prevention. (2024). Most recent national asthma data. U.S. Department of Health and Human Services. https://www.cdc.gov/asthma/most_recent_national_asthma_data.htm

2. Office of the Assistant Secretary for Planning and Evaluation. (2024). HHS poverty guidelines for 2025: Detailed guidelines and resources. U.S. Department of Health and Human Services. https://aspe.hhs.gov/sites/default/files/documents/dd73d4f00d8a819d10b2fdb70d254f7b/detailed-guidelines-2025.pdf

3. Xia, T., et al. (2023). Cost-related medication nonadherence in U.S. adults with asthma: National Health Interview Survey 2013–2020. Annals of Allergy, Asthma & Immunology. Advance online publication. https://doi.org/10.1016/j.anai.2023.07.013

4. Congressional Budget Office. (2025, June 4). Letter to Senators Wyden, Pallone, and Neal . U.S. Congress. https://www.cbo.gov/system/files/2025-06/Wyden-Pallone-Neal_Letter_6-4-25.pdf

5. National Rural Health Association. (2025). Impacts of the One Big Beautiful Bill (OBBB) on rural communities. https://www.ruralhealth.us/nationalruralhealth/media/documents/advocacy/2025/obbb-impacts-on-rural-communities_06-20-25-final_v3-(002).pdf

6. Center on Budget and Policy Priorities. (2025). Medicaid cuts would reduce access to health care for entire communities. https://www.cbpp.org/blog/medicaid-cuts-would-reduce-access-to-health-care-for-entire-communities

7. Tiotiu, A. I., Novakova, P., Nedeva, D., Chong-Neto, H. J., Novakova, S., Steiropoulos, P., Kowal, K., & Seys, S. F. (2020). Impact of air pollution on asthma outcomes. International Journal of Environmental Research and Public Health, 17(17), 6212. https://doi.org/10.3390/ijerph17176212

8. Centers for Disease Control and Prevention. (2024). Air pollutants. U.S. Department of Health and Human Services. https://www.cdc.gov/air-quality/pollutants/index.html

9. American Lung Association. (2025). State of the Air 2025. https://www.lung.org/getmedia/5d8035e5-4e86-4205-b408-865550860783/State-of-the-Air-2025.pdf

10. U.S. Environmental Protection Agency. (2024). Indoor Air Quality.  https://www.epa.gov/report-environment/indoor-air-quality

11. Ng, A.E. & Boersma, P. (2023). NCHS Data Brief, no 460: Diagnosed allergic conditions in adults: United States, 2021. National Center for Health Statistics. https://dx.doi.org/10.15620/cdc:122809

12. Zablotsky, B., Black, L.I., & Akinbami, L.J.(2023). NCHS Data Brief, no 459: Diagnosed allergic conditions in children aged 0-17 years: United States, 2021. National Center for Health Statistics. https://dx.doi.org/10.15620/cdc:123250

13. Climate Central. (2021). Pollen & Allergy Season. https://www.climatecentral.org/climate-matters/pollen-allergy-season

14. Zhang, Y., Bielory, L., Mi, Z., Cai, T., Robock, A., Georgopoulos, P., & Kinney, P. L. (2022). Projected climate-driven changes in pollen emission season length and magnitude over the Northern Hemisphere. Nature Communications, 13, 1236. https://doi.org/10.1038/s41467-022-28764-0

15. Anderegg, W. R. L., Abatzoglou, J. T., et al. (2021). Anthropogenic climate change is worsening North American pollen seasons. Proceedings of the National Academy of Sciences, 118(7), e2013284118. https://doi.org/10.1073/pnas.2013284118

16. Centers for Disease Control and Prevention. (2023). Asthma and Secondhand Smoke. U.S. Department of Health and Human Services. https://www.cdc.gov/tobacco/campaign/tips/diseases/secondhand-smoke-asthma.html

17. Patra, K. (2017). Tobacco and Children with Asthma. American Academy of Pediatrics. https://www.healthychildren.org/English/health-issues/conditions/tobacco/Pages/Tobacco-and-Children-with-Asthma.aspx

18. Centers for Disease Control and Prevention. (2024). Cigarette Smoking. U.S. Department of Health and Human Services. https://www.cdc.gov/tobacco/about/index.html

19. James, J., George, G., Cherian, M., & Rasheed, N. (2022). Thirdhand smoke composition and consequences: A narrative review. Public Health and Toxicology, 2(2), 1–6. https://doi.org/10.18332/pht/151102