Air pollution has been a pressing issue for decades and is undeniably linked to the environment and human health. In fact, air pollution continues to be the world’s largest environmental health threat.
Due to a decades-long increase in carbon emissions, urbanization, and climate change, more areas are facing the challenge of poor air quality. This is a major issue. Air pollutants can not only cause health problems, but they also pose a significant threat to the environment. Unfortunately, more than 100 million people in the U.S. live in places with poor air quality.
Poor air quality can result from many sources: industrial pollution, environmental incidents, vehicle emissions, wildfires, and natural causes. Unfortunately, air quality is getting worse, potentially harming homeowners and renters across the United States. As such, air quality information is more important than ever. It's crucial to understand these risks and take steps to protect your home and community.
To help current and future home searchers understand the impact of climate change on air quality in their area, Redfin has partnered with climate nonprofit First Street to show the Air Factor® for every property on Redfin.com. Air Factor® builds off of decades of peer-reviewed research to show the current and future outdoor and indoor air quality risk for every home, city, and county so homebuyers and homeowners have all the information they need when deciding where to live.
Air Factor® analyzes the two most common harmful air pollutants: fine particulate matter (PM2.5), and ozone. PM2.5 is emitted from wildfires and other man-made sources, including vehicles and other fuel consumption. Ozone forms when many common pollutants react with sunlight. Other pollutants are flagged on the Risk Factor™ website. The EPA notes that many human-caused pollutants are falling, but overall pollution is rising.
Air Quality Risk FAQs
How is air quality measured?
- AQI 0-50: Good
- AQI 51-100: Moderate
- AQI 101-150: Unhealthy for Sensitive Groups
- AQI 151-200: Unhealthy
- AQI 201-300: Very Unhealthy
- AQI 301-500+: Hazardous
Established by the Environmental Protection Agency (EPA), the AQI measures five harmful air pollutants regulated by the Clean Air Act: ground-level ozone, particulate matter (PM2.5 and PM10), carbon monoxide, sulfur dioxide, and nitrogen dioxide.
How does poor air quality affect your home?
While many pollutants originate outdoors, they regularly find their way indoors. Airborne pollutants such as particulate matter (PM2.5), ozone (‘smog’), pollen, mold, and volatile organic compounds (VOCs) can lead to respiratory problems, heart diseases, cancers, allergies, and other health concerns.
Mold and mildew are common culprits for internal structural damage. Other pollutants, notably particular matter, ozone, and sulfur and nitrogen oxides, can prematurely deteriorate building materials and harm the longevity of your home.
How can you improve air quality at home?
- Install an air purifier with a HEPA filter and air quality monitor
- Maintain HVAC systems and replace filters
- Install highly-insulated windows, doors, and building materials
- Open windows and circulate air using fans
- Clean and dust regularly
- Use natural cleaners and avoid scented products
- Don’t use air fresheners
- Switch to electric appliances
- Don’t burn anything indoors unless necessary
In the long term, supporting clean energy, practicing sustainable habits, developing urban forests, and advocating for air quality regulations are important actions you can take to reduce the impact of pollution.
What types of air pollution are the most common?
- Pollen
- Mold
- Dust mites
- Sulfur dioxides
- Carbon monoxide
- Asbestos
- Lead
- PFAS
- VOCs
How does climate change affect air quality?
Pollutants are increasing primarily because climate change creates longer warm seasons and shorter cold seasons, allowing hot, stagnant air to accumulate and harmful air pollutants to build up in an area. Hotter temperatures have also been shown to lead to an increase in natural disasters, including wildfires, and allow ozone to build up more quickly.
Additionally, longer warm seasons can mean longer pollen seasons and less relief during the winter. More frequent rainfall and flooding may also lead to more mold growth.
How do wildfires affect air quality?
Are wildfires getting worse?
What is ozone pollution?
Air quality and equity
Additionally, people who are farm workers, firefighters, roofers, and construction workers are more likely to be impacted by air quality risks, especially as climate change progresses.
The Top 10 U.S. Metros With the Highest Risk of Air Pollution
Rank | Metrp | Share of Properties With High Air Factor® Risk | Total Properties With High Air Factor® Risk |
---|---|---|---|
1 | Portland, OR | 100% | 866,949 |
2 | Seattle, WA | 100% | 863,100 |
3 | Sacramento, CA | 100% | 795,662 |
4 | Okaland, CA | 100% | 749,426 |
5 | San Jose, CA | 100% | 477,662 |
6 | San Francisco, CA | 100% | 350,664 |
7 | Tacoma, WA | 100% | 306,393 |
8 | Fresno, CA | 100% | 293,100 |
9 | Spokane, WA | 100% | 241,422 |
10 | Stockton, CA | 100% | 225,796 |
High risk is defined as a property having an Air Factor® of 5 (major) or higher. Since 90 metros (all in the Western U.S.) have 100% of properties at risk, table is sorted by total properties at risk.
This page is for informational purposes only and is not a substitute for professional advice from a medical provider. Consumers should independently verify any claim, agency, or service mentioned.