LandWatch State of Monterey County Report 1998
3.8 Air Quality

Monterey County is part of the North Central Coast Air Basin. The Basin currently meets the federal ozone (smog) and particulate matter standards. Because the federal ozone standards were met in 1990, the Basin was redesignated to a federal attainment area in 1997 (clean air area).(4)

The Basin continues to violate the California ozone and particulate matter standards that are more stringent than federal standards; however, the number of violations has declined over the years. In 1987, there were 34 days exceeding the State ozone standard; in 1996, there were 21, and in 1997, there were two. None of the 1996 or 1997 violations occurred in Monterey County. Fifty percent of recent violations are the result of transport from the San Francisco Bay Area (i.e., the violations would have occurred even with no emission contribution from the North Central Coast Air Basin).

Emission forecasts for pollutants that form ozone show a decline to about 2010, after which they begin to increase; that is, emission growth begins to overtake emission controls. Thus, ozone levels will increase after 2020 unless additional controls are implemented. Major sources of ozone forming emissions include mobile sources, solvents, Moss Landing Power Plant, manufacturing, and industry.

Most violations of the California standard for particulate matter of ten microns or less in diameter (PM10) have occurred at coastal stations where sea salt is the primary reason for violations. Aside from violations at the coastal Moss Landing air monitoring station, there has been only one violation elsewhere in Monterey County since 1994. PM10 emissions are projected to increase over the years due to increases in vehicle travel. (10) Major sources of PM10 include vehicle travel on paved and unpaved roads, windblown dust from open fields, and farming operations.