AREA SUFFERS HIGH OZONE LEVEL; SANTA CLARITA'S UNHEALTHY AIR DAYS TIED FOR SECOND IN COUNTY.

Byline: Erin Gebroe Daily News Staff Writer

The Santa Clarita Valley tied with Pomona as the second-most unhealthful area in Los Angeles County last year in terms of the number of days health advisories were issued, according to preliminary figures released by the South Coast Air Quality Management District.

Ozone levels caused both areas to endure eight days of health advisory.

During a health advisory, air quality officials recommend that people avoid vigorous outdoor activities like jogging or playing basketball.

The east San Gabriel Valley garnered the most days of health advisories, with 19.

While the Santa Clarita Valley had eight health advisory days in 1998, it saw just two in 1997.

``That's a significant increase, obviously, and I think greater than we saw in some other areas,'' AQMD spokesman Bill Kelly said.

Health advisories are issued when the amount of ozone reaches 0.15 parts per million in a one-hour period.

Ozone forms when hydrocarbons and nitrogen oxides combine in the presence of sunlight. Levels tend to rise from May to October, when there is more sunlight.

A regional, as opposed to local pollutant, ozone typically gets blown from the western portion of the Los Angeles basin, which includes downtown Los Angeles, to the far inland valleys, including Santa Clarita, AQMD spokesman Sam Atwood said.

The path of ozone, which is guided by winds, helps explain why Santa Clarita had more health advisories last year than the previous year.

``As we have cut the amount of the pollution, it's taking longer for the ozone to form, and that means (ingredients of ozone are) blowing farther downwind before it does form,'' Kelly said.

Another explanation is El Nino, which brought rain in 1997, keeping smog levels lower.

``We did see more days of unhealthy smog levels in 1998 due to a return to normal weather patterns,'' Atwood said.

In addition to health advisories, the Santa Clarita Valley endured 38 days in which ozone levels exceeded state standards and 16 days in which they exceeded federal standards, which are less strict, according to the AQMD's 1998 figures.

Final tallies will be released in April, Atwood said.

Although ozone is invisible, its effects on people are not.

Exposure to the gas, a form of oxygen, may lead to shortness of breath, chest pain when inhaling deeply, wheezing and coughing, and lung damage similar to that caused by cigarette smoking, according to the American Lung Association.

Long-term exposure could lead to inflammation of the lung lining and increased respiratory discomfort.

People especially prone to problems from excessive ozone exposure include those who exercise outdoors and people with pre-existing respiratory disease.

Although ozone is a regional problem, individual cities can help reduce the amount of ingredients that form ozone, Kelly said.

``Thinking is increasingly that development policy or zoning policy can help decrease pollution by making it possible for people to not have to use their cars as much,'' Kelly said.

Lynne Plambeck, a member of the Santa Clarita Organization for Planning the Environment, is one of those thinkers.

Plambeck said areas should be compact instead of sprawling so people can walk more often. Additionally, public transportation should be more accessible, she said.

``We just need to pay attention to the way we build,'' Plambeck said. ``Because we're just starting to build up our downtown, we could incorporate a lot of those ideas. That's the way we're going to have to deal with ozone.''

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BOX: OZONE AIR QUALITY:These figures show the number of days that ozone levels prompted health advisories in 1998 in select communities. Also shown are numbers of days ozone levels exceeded state and federal standards, according to preliminary figures from the South Coast Air Quality Management District.