Air Quality

Air pollution is a serious public health problem. Although the Bay Area has remained one of the cleanest of the five major urban California air basins in recent years, there are still several days annually when air pollution exceeds the federal and state air quality standards.

These standards, set at different concentrations for each of the major air pollutants, were developed to protect public health. The EPA has in turn devised a system to translate these standards into a simple, easy-to-understand, color-coded number scale that tells you whether or not the air is healthy to breathe. This system is called the Air Quality Index.

We can all help keep air pollution down by making the right "clean air choices" — personal decisions that make a difference in the quality of air we breathe. The single largest source of pollution in the Bay Area is the motor vehicle. On days when the air quality is forecast to be unhealthy, we can all make a big contribution to cleaner air by driving less.

Woodsmoke in My Neighborhood
The nine counties that surround San Francisco Bay are home to almost seven million residents and an estimated 1.7 million fireplaces and woodstoves. Woodsmoke air pollution from these woodburning appliances has been a health concern in the Bay Area for many years, especially on winter evenings.