For the second year in a row, the greater Los Angeles metropolitan area has not had a single Stage 1 ozone episode when air quality is very unhealthy, proving that such ozone levels are a thing of the past.
With rainy conditions predicted, Southern California's 2000 smog season has drawn to a close.
"AQMD's Air Quality Management Plan predicted an end to Stage 1 episodes by the year 2000, and our air pollution control programs have allowed the region to meet that milestone," said Barry Wallerstein, AQMD's executive officer.
As of Oct. 26, there had been 40 days of unhealthy air quality when the federal standard for ozone, 0.12 parts per million averaged over one hour, was exceeded. There were 41 unhealthy air days in 1999 and 62 in 1999, reflecting a long-term trend of significantly improved air quality.
Since 1985 there has been a 75% reduction in the number of days of unhealthy air quality, or an average of better than 7 fewer unhealthy air days each year.
This year, several areas, including coastal and south central Los Angeles County, north coastal Orange County, the west San Fernando Valley, Lake Elsinore and the Coachella Valley did not have a single exceedance of the federal ozone standard.
Southland residents have not experienced a Stage 1 episode since 1998. Stage 1 episodes, declared when ozone averages 0.20 parts per million for an hour, reached their peak in 1977 with 121 days -- one in three during that year -- attaining the very unhealthy level.
Air quality has improved so much in Southern California that the area, for the second year in a row, no longer has the worst ozone pollution in the nation. The Houston metropolitan area had more unhealthy days this year -- 44 compared to 40 here -- as of Oct. 26. Houston also had a higher peak ozone level -- 0.225 parts per million, exceeding California's Stage 1 level, compared to 0.18 in the Los Angeles Basin. Several other areas of the state and nation had slightly lower levels than Southern California.
The Southland experienced 17 ozone Health Advisories this year, when ozone levels exceed 0.15 parts per million and residents are advised to curtail vigorous and prolonged outdoor exercise. That number is slightly up from 12 in 1999, but considerably down from 43 in 1998 and higher numbers in previous years. Some variation is expected from year to year due to weather and wind conditions.
This year's continued trend of improved air quality occurred in spite of several periods of high temperatures and stagnant air inversions conducive to smog formation.
AQMD is the air pollution control agency for Orange County and the urban portions of Los Angeles, San Bernardino and Riverside counties.
-#-
AQMD Home Page
This page updated: March 01, 2004
URL: http://www.aqmd.gov/news1/Smog_Season_2000.html