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Mar 08

Learn the facts about Bay Area air pollution

Posted on March 8, 2021 at 8:31 pm by Clay Curtin

The Bay Area Air Quality Management District works year-round to educate the public about the various sources of air pollution, how to protect yourself from the harmful effects and what you can do to help improve air quality throughout the region. The most common pollutants that affect air quality and public health in the Bay Area are ozone and particulate matter pollution:

Ozone pollution, also known as smog, can be a health hazard during the warmer months. Each day, air pollution builds up from cars and trucks on Bay Area roads. On hot days, pollution reacts with heat and sunlight to create ozone. When inhaled, ozone pollution can cause negative health effects, including irritation of the eyes, nose and throat, as well as trigger serious long-term health effects such as asthma aggravation, heart disease and more. On hot days when ozone may reach unhealthy levels, a Spare the Air Alert is called. The best way to improve air quality and reduce ozone pollution is to reduce your driving.

Particulate matter pollution consists of microscopic particles that come primarily from residential wood burning, as well as wildfire smoke, and can have immediate health impacts. These fine particles easily bypass the body’s natural filtration system, enter the lungs and even the bloodstream. Particulate matter can cause lung irritation and inflammation, exacerbate respiratory conditions and trigger asthma attacks. Particulate matter pollution from wood burning mainly occurs in the winter months. On cold, calm days, wood smoke can become trapped close to the ground by an inversion layer, typically formed when a layer of warm air acts as a lid over a layer of cooler air. Inversions prevent the air below from rising, which causes pollutants to build up. When particulate pollution is forecast to reach unhealthy levels, a Spare the Air Alert is called, and the use of all wood-burning devices indoors and outdoors is prohibited. Exemptions are available to residents whose sole-source of heat is an EPA-certified wood burning device that is registered with the Air District. 

In response to increasing smoke impacts from wildfires, an amendment to the Wood Burning Rule was adopted in 2019, allowing the Air District to ban wood burning year-round when a Spare the Air Alert for particulate pollution is called. 

Spare the Air Alerts are issued to notify the public when air quality is forecast to be unhealthy and to share information on ways to reduce air pollution. Bay Area residents can find out if a Spare the Air Alert is in effect by:
  • Signing up for text alerts by texting the word “START” to the number 817-57
  • Calling 1-877-4NO-BURN
  • Visiting or
  • Signing up for automatic email or phone Air Alerts at
  • Downloading the Spare the Air iPhone or Android app
  • Following Spare the Air on Facebook, Twitter and Instagram