Tom Jordan, special projects director for the San Joaquin Valley Air Pollution Control District, said the area has made some gains in controlling pollutants such as carbon monoxide in the 13 years since his organization was created.
Ozone and particulate matter, however, continue to plague the Valley's air quality, he said.
"We hadn't cleaned up far enough fast enough," Jordan told an audience of 50 at a Merced County League of Women Voters forum in Merced.
Jordan said ozone, also known as smog, takes its greatest toll on air quality in summer months. It can cause sore throats, coughing and fatigue. Controlling it means working out new plans for cars and factories that emit the chemical.
Particle pollution does the most harm in the fall and winter, though for different reasons.
Tiny particles of dust from Valley agriculture can pollute the air during the fall harvest season, causing respiratory problems for some people.
In the winter, fog traps particles from vehicle exhaust and fireplaces, posing a greater health danger, Jordan said.
He said the district is preparing a new plan to clean its air by 2010, its third deadline to meet federal air-quality standards.
Mary Michal Rawling, project manager for the Merced-Mariposa Asthma Coalition, encouraged the audience to be mindful that poor air quality can cause asthma in children.
"Yes, we're worse than L.A.," she said, pointing to a graph showing that the Valley suffers more bad air days for longer periods of time than Southern California's notoriously bad air.
Diana Westmoreland Pedrozo, executive director of the Merced County Farm Bureau, said new air-quality restrictions are taking an inordinate toll on the Valley's agriculture industry.
Farmers received some air quality exemptions for the past 50 years, but those are ending, creating new problems for the state's agriculture industry, she said. Some of these restrictions will limit burning and use of diesel engines.
"I'm not even sure what agriculture's contribution (to air quality problems) is -- my guess is 25 percent, maybe. We're getting 100 percent of the burden," she said.
Reporter Adam Ashton can be reached at 385-2484 or aashton@mercedsun-star.com.
