Even with an improved ranking, Imperial County still rated an "F" from the American Lung Association for its levels.
Air-quality issues affect lung health in general, American Lung Association of San Diego and Imperial Counties vice-president Jan Cortez said at a press conference Wednesday.
"Imperial County has the state's highest hospitalization rates for childhood asthma," Wednesday's report states.
In areas where air quality is poor, there is more asthma and more respiratory problems.
The county had 35 bad ozone days for the year. Of those, 32 days had an unhealthy amount of ozone for sensitive groups, which include children, the elderly, people with chronic respiratory problems and those who work outdoors. Three days were unhealthy for all residents.
California dominated the list of 25 counties with the worst ozone air pollution with 11 counties. The top five are in California.
San Bernardino County had the worst ozone with 50 days of very unhealthy levels of ozone, 50 days of unhealthy levels and 165 days of unhealthy levels for sensitive groups.
In another category, metropolitan areas, California took the top four of 25 for the third year in a row. The Los Angeles-Riverside-Orange County metropolitan area has the most ozone pollution in the country, followed by Bakersfield, Fresno and the Visalia-Tulare-Porterville area.
While Imperial County flunked in ozone, a bigger problem locally is PM-10, or dust matter smaller than 10 microns. (A human hair is about 75 microns in diameter.) The county does not meet air-quality standards for PM-10.
Small air particles in Calexico have been measured at 10 times above federal air-quality standards and more than double what the government says causes significant harm to health, the association's report states.
A new concern is dust from exposed land at the Salton Sea if water levels drop. Water levels could drop if the San Diego County Water Authority-Imperial Irrigation District water transfer takes water from farmers for irrigation, a byproduct of which is ag runnoff feeding the sea.
The American Lung Association weighed in on the potential problem April 12 saying toxic particles such as selenium, cadmium and arsenic found in the sea bed would make dust storms more unhealthy.
The association does not do a national scale report on particulate matter.
Visit the American Lung Association on the Web at: www.lungsandiego.org
>> Staff Writer Laura Mitchell can be reached at 337-3452 or firstname.lastname@example.org