We meet high standards for improving our air and water quality, protecting and restoring the natural environment and conserving natural resources. High-quality air is fundamental to the health of people, nature and our economy. The number of days Silicon Valley air exceeds ozone standards is an indicator of air contamination. Ozone is the main component of smog and is created when volatile organic compounds and nitrogen oxides are exposed to sunlight.
Vehicles are the primary source of such emissions.
In 1999, Silicon Valley experienced one bad-air day as measured against the federal ozone standard, down from three in 1998. The region exceeded the stricter state standard 12 days, compared to 21 days in 1998. The health of bays, lakes and rivers depends on the health of their watershed, the land area from which all water drains. Without careful planning, development, road construction and agriculture can adversely affect watershed quality by contributing sediment from erosion and by releasing contaminants such as household chemicals, oil and debris from roads, and fertilizer and pesticide runoff. The U.S. Environmental Protection Agency has developed a composite rating of the Santa Clara Basin's overall watershed health.