The San Joaquin Valley’s air quality is better than it has been in decades but it still isn’t clean enough to meet all federal standards.

The truth is that even if nobody lived in the valley and there were no businesses or cars, it would still be polluted because of its distinctive topography and pollution blown in from the neighboring Bay Area, said Seyed Sadredin, executive director of the San Joaquin Valley Air Pollution Control District.

“The valley is like a bowl,” he said. “Because of temperature conditions in the summer and winter, we have a blanket over the valley that keeps the pollution trapped in here for long periods of time.”

The district has had some victories. Its eight counties (San Joaquin, Stanislaus, Merced, Madera, Fresno, Kings, Tulare and Kern) have reduced air pollution from businesses by 80 percent since 1980. And, for the first time this summer, the valley had zero violations of the hourly ozone standard – a huge improvement from 1996, when the valley had 281 violations of the standard.

But as the science advances, the Environmental Protection Agency keeps raising the bar for clean air, lowering the allowed amount of ozone and particulate matter. “Every five years, the EPA moves the goal post,” Sadredin said. “Our passing grades have become tougher.”

What makes it more difficult, he says, is that more than 80 percent of emissions come from trucks and cars, which the district cannot control. But the EPA insists the valley must meet the same air quality standards as the rest of the nation, and has refused to lift economic sanctions.

Air pollution causes suffering for many valley residents. Summer ozone causes respiratory irritation and aggravates problems like asthma. Winter problems with particulate matter (microscopic specks of soot) is much more dangerous. It can cause blood clots and even prompt heart attacks.

“Air pollution is a very serious health problem – it’s not just a nuisance,” said Bonnie Holmes-Gen, senior director of policy and advocacy for the American Lung Association in California. “It’s not just a haze that obscures our vision or causes us to cough a bit. It contributes to asthma attacks, shortness of breath, hospitalizations and premature death.”

The most vulnerable are young children and the elderly, said Dr. David Lighthall, the air pollution control district’s health science advisor.

Young children are breathing more rapidly so are exposed to a higher level of pollution than adults. “It’s pretty well established that children who are exposed chronically to ozone and especially particle pollution- by the time they’re adults, some of them are going to lose lung function relative to kids who didn’t grow up in that kind of environment,”Lighthall said.

Older adults are more at risk because their immune system is diminished and they are more likely to have a chronic disease like asthma or diabetes. Modesto, which is in the valley, was recently named one of the seven worst cities in America to retire in part because of its poor air quality.

Irene, an 86-year-old resident of Casa de Modesto retirement center in Modesto who doesn’t want to disclose her last name, has been so troubled by air pollution in recent years that she sometimes can’t go outside. She has shortness of breath in the winter.

“I just can’t do anything,” she said. “When I can’t breathe any more, I have to just stop and rest.”

Brenda Hurst, the 51-year-old office manager at Casa de Modesto, has such terrible problems with asthma and bronchitis that she is considering moving from the area, where she has lived since fifth grade. When she visits her daughter in Huntington Beach, she is fine. But in the valley, she constantly coughs. “I’m conscious of every breath I take,” she said. “You shouldn’t be thinking about breathing on an everyday basis.”

While most people can live in the valley without such serious hardship, “some people just can’t live here,” Lighthall said.

The air pollution district educates the public on what to do to reduce air pollution. Its most successful endeavor has been its “Check Before You Burn” campaign limiting fireplace use. It has reduced 18 tons a day of particulate matter, for a total of 30 percent reduction of particulate matter in the winter.

“A lot of people love burning wood and we got a lot of hate calls,” Sadredin said. “But I think there’s a greater acceptance.”

Fireplace use is regulated because when the winter air is stagnant, the smoke coming out of chimneys is not rising away- it’s drifting back down to ground level and into people’s homes.

The district has had a more difficult time signing up businesses to be Healthy Air Partners and participate in campaigns like Air Friendly Fridays, which encourages workers to carpool or bicycle commute or walk on that day. Out of the thousands of valley businesses, only a few hundred have enrolled – something that concerns Sadredin. “If people don’t sign up voluntarily, we may have to make these programs mandatory down the road.”

But some businesses are enthusiastic supporters. Modesto’s Center for Human Services has a Green Committee, which educates employees on how they can reduce air pollution and help the environment in general.

Seng Xiong, co-chair of the committee, said she distributes the air pollution control district’s Healthy Air Living newsletter each month and posts notices on a bulletin board about no burn days. Two years ago, the center installed bike racks. The center also encourages employees to link trips – make several stops in one trip instead of making separate trips.

Kaiser Permanente Fresno encourages bicycling and telecommuting and also flies different colored flags that alert staff and patients about the air quality of the day.

This winter air pollution has been particularly bad in the valley. In December, the soot level was four times higher than federal standards. But it could be worse.

“In China or Mexico, you don’t have to measure the air pollution,” Sadredin said. “You wipe it off your face.”