In the Bay Area, a certain amount of air pollution comes from industrial sources, such as refineries and power plants. But a greater percentage of harmful air emissions come from cars and trucks, construction equipment, and other motor vehicles. In the wintertime, the largest single source of air pollution is residential wood burning.

Types of Air PollutionWood Smoke

In order to protect public health, the U.S. EPA and the state of California have created air quality standards for pollutants that are commonly present in the air we breathe. 

In the Bay Area, the common pollutants of greatest concern are ozone and fine particulate matter. Ozone is the main ingredient in summertime smog, and fine particulate matter - which is made up of an assortment of extremely small airborne particles, or mixtures of solid particles and liquid droplets - is primarily a problem in the wintertime. 

The state of California has also identified a category of air pollutants called toxic air contaminants. These are generally present in very small amounts in the air, but are extremely hazardous to human health. In the Bay Area, the toxic air contaminant of greatest overall concern is exhaust from diesel engines.

What You Can Do

CongestionAs a Bay Area resident, there are a number of things you can do to reduce air pollution:

Drive Less
The most important thing is to drive less - take public transit, carpool, bike, or walk whenever you can to get to work, shopping, or wherever you need to go.  and  are good resources for finding a way to go places without using your car.

Burn Less Wood 
In the wintertime, burning less wood can make a big difference in local air quality and will help protect the health of your family and neighbors. It is illegal in the Bay Area to burn wood when a Winter Spare the Air Alert is in effect.

Spare the Air
The Air District created the Spare the Air Program to educate residents about air pollution, encourage actions to improve air quality in the Bay Area, and to provide advance notice when air quality is expected to be unhealthy. As part of the Spare the Air Program, the Air District asks residents to reduce pollution by making clean air choices every day. This can include walking and biking more often, taking transit, telecommuting or carpooling, driving less, reducing energy consumption at home, and making many other daily choices that improve air quality. The Air District’s Spare the Air website provides many tips and resources for reducing air pollution