Tens of thousands of people in Stanislaus, Merced, Tuolumne and San Joaquin counties are at heightened risk of premature death because of dirty air, according to a report released Thursday.
The American Lung Association's "State of the Air: 2004" says the four counties and 30 others in California failed clean-air tests for ozone pollution, commonly known as smog, and for microscopic, sootlike particles that increase health risks for people, particularly those with cardiovascular and lung diseases.
It's the first time the association's annual study has included particle pollution data, which became available through a newly created national air quality surveillance network.
The Modesto and Merced metropolitan areas ranked among the 25 communities in the nation with the worst exposure to the tiny particles.
Modesto was 11th, and its metropolitan area -- essentially the entire county -- had more than 169,000 people in the two age groups most vulnerable to the pollution. That includes people 14 and younger and 65 and older. There are 482,440 people in the region.
The greater Merced area ranked 23rd for particle pollution and was the sixth-worst ozone-polluted community in the nation. Of the 225,398 in the greater Merced area, an estimated 82,600 people are in the vulnerable age groups and there are 24,339 people who suffer from respiratory illnesses such as asthma, chronic bronchitis and emphysema.
Such studies on the valley's dirty air are no surprise to health officials, but they are a concern.
"From a public health perspective, our greatest concern is that air pollution exacerbates respiratory illness and heart disease," said Dr. John Walker, Stanislaus County's public health officer.
In the study, Stanislaus and Merced counties got failing grades for particle pollution during 24-hour periods and over an entire year. Also, those counties failed the test for ozone pollution.
San Joaquin County flunked the test for particle pollution, but improved from an F to a D grade for smog. In addition, the air was not all that fresh over the foothills of Tuolumne County, which failed the test for ozone.
According to the report, 24.3 million people in California are at risk from ozone air pollution and 22.7 million are in danger from exposure to particle pollution.
Produced by oil refineries, agriculture, wood burning and other sources, particle pollution can be dangerous when unhealthy levels persist over a long period of time, or even if the levels occur for only a few hours or days.
Studies link particle pollution to increased risk of asthma attacks, heart attacks and strokes, lung cancer and premature death, the study says.
People with cardiovascular diseases, children and the elderly are most vulnerable to the health risks associated with particle pollution. So are people who suffer from chronic lung disease.
When inhaled, the fine particles embed themselves deep in the lungs and may even pass through the lungs to the blood. Researchers are still trying to sort out the different ways the contaminants damage the body.
"This report is a wake-up call for Californians to realize that we are breathing unhealthy air in our own communities," said Dr. John Balmes, a spokesman for the American Lung Association. He is involved in a Fresno study into links between air pollution and children with asthma.
"The threat may be invisible to the human eye, but it is real and it can kill," he said.
The health risks are why the association is fighting what it sees as Bush administration efforts to weaken the Clean Air Act.
Balmes said that pollution in the San Joaquin Valley is a two-pronged problem. Development, which brings more cars and trucks to the valley, increases the amount of tailpipe emissions. In addition, the valley gets regular doses of smog drifting over the Diablo Range from the Bay Area.
Balmes said valley communities need to pay closer attention to what urban development does to their air basin.
"Development is good for the economy, but you can't just develop and develop without thinking about what it does to the air quality," he said.
Since children are more vulnerable to the adverse health effects of air pollution, the study says that choosing a cleaner-fueled vehicle goes a long way toward protecting their health.
The study was based on air quality measurements made by state and local agencies and reported to the Environmental Protection Agency for the years 2000 through 2002. Communities received from top to failing grades based on how often air pollutants reached unhealthy levels under the EPA's air quality indexes.
Darlene DeMarco, director of the association's Valley-Lode branch, said the association has a San Joaquin County program for children five and younger who suffer from asthma. Nurses provide home evaluations, and instruct family members in the use of inhalers and the proper way to take medications.
The study, "State of the Air: 2004" can be viewed at www.californialung.org.
Bee staff writer Ken Carlson can be reached at 578-2321 or firstname.lastname@example.org.
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