Larry Allen, county air pollution control officer, was in for a nasty shock when he saw the latest annual air quality report from the American Lung Association. It listed San Luis Obispo County as having the ninth worst air quality in the nation.
The report showed that from 2006 to 2008 the county exceeded federal air standards for ozone on 93 days. This is a worse record than other areas of the state that are notorious for their air pollution problems, such as Merced, El Centro and Modesto.
Not fair, Allen said.
All but four of those bad air days were recorded at two monitoring stations along the county’s eastern border. Of the other four, two were in Atascadero, one was in San Luis Obispo and one was in Morro Bay.
Only the two violations in Atascadero are considered homegrown incidents, Allen said. The other two were caused by massive wildfires burning in Santa Barbara County at the time.
“In their report, it makes it look like we have the ninth worst air quality in the nation, whereas 99 percent of our population lives in areas that meet federal air standards,” Allen said. “It presents a confusing message to our residents.”
Ozone is one of two major types of air pollution regulators monitor. It is formed when emissions from cars and other sources react to heat and sunlight. Ozone — often called smog — irritates the lungs and causes asthma and other lung diseases.
The two monitoring stations that accounted for the lion’s share of the violations were in the Carrizo Plain in the southeastern corner of the county and at Red Hills, a remote location near the Kern County line east of Paso Robles.
Both of these locations are at higher elevations and are exposed to a persistent band of ozone formed in the Central Valley, Los Angeles and San Francisco Bay areas and transported by winds throughout the state, Allen said.
Because of these higher ozone levels, particularly during the hot summer months, Allen’s agency in May instituted its first air quality flag warning system at the elementary school in the Carrizo Plain. Color-coded banners are flown from the school’s flagpole, notifying residents of that day’s air quality.
This is not to say that the populated areas of the county are entirely free of air quality problems, Allen said. The North County communities of Atascadero and Paso Robles occasionally violate ozone standards.
The Nipomo Mesa also has high particulate levels. A recent study by the air pollution control district pinpointed sand blowing inland from Oceano Dunes State Vehicular Recreation Area as the source of the particulate pollution.
Nation’s top ten smoggiest areas
1. Los Angeles-Long Beach-Riverside
5. Greater Sacramento area
7. Houston-Huntsville, Texas
8. Greater San Diego area
9. San Luis Obispo County
10. Charlotte, S.C.
SOURCE: American Lung Association