Reporting on the impact of climate change on indoor air quality

The average American spends about 90% of their day inside, according to the EPA, so indoor air quality (IAQ) affects just about everyone.

IAQ is a public health term that describes the contents of the air inside and around structures in relation to health. As a health care reporter, it is important to help your readers understand indoor air pollutants, assess and measure their risks and connect how some negative health outcomes are made worse by a changing climate.

More frequent heat waves are driving people inside their homes to escape the heat, while temperatures are also rising inside. Outdoor air infiltrates into indoor environments, bringing harmful pollutants like ozone, particulate matter and allergens like pollen with it.

Federal and state laws regulate the quality of water, food, drugs and outdoor pollution, but there are no comprehensive regulations for indoor air quality - only limits on certain pollutants. A good place to start when writing about indoor air pollution is to contact local health departments or environmental agencies for specific guidelines and resources relevant to your area.

Pollutant sources and their effect on indoor air quality

Fuel-burning combustion appliances

Carbon monoxide (CO) is produced from the incomplete combustion of fuels, often used in heating or cooking. The toxic, colorless and odorless gas can build up when homes are not properly ventilated or when appliances are not maintained, causing nausea, dizziness and death, if not treated immediately.

PBS recently aired a segment on why carbon monoxide poisoning is on the rise as extreme weather causes more power outages. And after Hurricane Beryl caused blackouts in Houston in July, the Houston Chronicle did some great reporting on how you can avoid CO poisoning while using a generator.

Smoke

Wildfire smoke has a number of toxic particles that can be carried inside the home and contribute to indoor particulate matter. People located in the western United States and in rural areas are particularly vulnerable to wildfire smoke exposure inside their homes. The Mayo Health Clinic System wrote an informative guide to understanding the health impacts of wildfire smoke.

Smoking tobacco is a known carcinogen, and smoking inside concentrates the risk while exposing others to secondhand smoke. Indoor particulate matter 2.5 (PM2.5) is a reliable marker of the presence of tobacco smoke, which is closely correlated to chronic lung diseases. Gas utilities used the tobacco industry's tactics to avoid gas stove regulations, a story that NPR dove into last fall.

Radon

Exposure to radon is a major cause of lung cancer worldwide, according to the World Health Organization. Approximately 3% to 14% of all lung cancer cases are attributed to radon exposure, depending on a country's average radon level and prevalence of smoking.

The naturally occurring gas is a result of decaying uranium and it can be easily tested for. In a paper published in Nature in February, researchers found rural communities experience higher radon exposure versus urban areas, potentially due to a higher usage of wells for water.. In January, HUD committed $3 million in grants for testing and mitigation of radon to hopefully improve indoor air quality and protect about 3,000 residents from risks posed by radon exposure.

Excess moisture

The Washington Post recently declared that we just lived through the most humid summer on record. Human-caused climate change has accelerated water cycles, causing record amounts of moisture in the atmosphere. This has spurred significant flooding in the US in 2024, often entering people's homes and places of work.

When moisture remains consistent indoors, it can lead to the proliferation of pathogens, mold, allergens and other biological contaminants. Exposure to mold and mildew can trigger allergic reactions, asthma and other respiratory issues. Ensuring adequate airflow and managing humidity levels are key strategies for improving indoor air quality.

Key EPA resources on indoor air quality and climate change

• Take Action for Climate Readiness and Indoor Air Quality
• Adapting Buildings for Indoor Air Quality in a Changing Climate
• Indoor Air Pollution: An Introduction for Health Professionals

Experts to contact

• Mehdi Amouei Torkmahalleh, Ph.D. - assistant professor at the University of Illinois Chicago in Environmental and Occupational Health Sciences
  Torkmahalleh's focus is on "community exposure to ultrafine particles from indoor, workplace, and anthropogenic sources and examine the associations between these exposures and neurodegenerative diseases."
• Lawrence Berkeley National Laboratory Indoor Environment Lab
  The lab works to "advance health, productivity and energy efficiency in the built environment." You can find a contact list for their researchers here.

Additional resources

• Indoor Air Pollution (visualized in data) - Our World in Data.
• Canadian Wildfire Smoke Is Triggering Outdoor Air Quality Alerts Across the Midwestern U.S. It Could Pollute the Indoors, Too - Inside Climate News.
• Inside is not the answer: Air quality in the Great Lakes - Great Lakes News Collaborative.
• EPA chooses Mountain West project to reduce air pollution in schools - Wyoming Public Media.