CLEAN AIR VICTORY NEAR L.A. ON TRACK TO MEET CARBON MONOXIDE GUIDELINES.

Byline: Lisa Mascaro Staff Writer

Southern California stands to score a major victory this winter in its war on smog, with the Los Angeles Basin likely becoming the country's last metropolitan area to come clean on carbon monoxide emissions.

Reducing the noxious fumes that come primarily from vehicle tailpipes wouldn't end the bad air days, but it would mark a milestone in the decades-long battle to meet federal air quality standards.

Los Angeles now meets federal standards for lead but problems remain in three other areas. If the basin can get through the winter without any high carbon monoxide days, it will get a clean bill of health for the second component of smog and face only the continuing struggle to reduce ozone and particulate matter.

The best weapon against carbon monoxide will be the weather.

Experts say if the coming months bring wind, rain or other conditions to whip up the air and avoid an inversion layer, it will allow carbon monoxide emissions to rise and disperse - although residents can also do their part by tuning up their car engines and driving less, if such a thing were possible.

``It really is a weather-dependent phenomenon at this point,'' said Joe Cassmassi, senior meteorologist at the South Coast Air Quality Management District. ``With El Nino developing and hopefully bringing us some rain this winter ... This may be the kind of assist that can help us out.''

Once the smog-choked region cleans up carbon monoxide, it still faces tough battles over ozone and particulate matter.

The South Coast is the last remaining metropolitan region in the nation to clean up carbon monoxide - a colorless, odorless gas that can cause physical ailments, and illness and death among those with cardiovascular disease.

While carbon monoxide has been steadily on the decline - thanks to newer, cleaner-burning cars and trucks - the basin's sunken landscape and often-present inversion layer keep emissions stubbornly locked in at higher-than-acceptable levels.

The region failed to meet its December 2000 deadline for cleaning up carbon monoxide. But with no violations in 2001 and just one logged so far this year, the L.A. area is on track to hit the mark by year's end.

The region must to go two full years with no more than one violation to be considered in compliance.

``I'd say it's a landmark, certainly,'' said David Jesson, a specialist in the Environmental Protection Agency's air division.

``We've essentially cleaned up the lead,'' he said referring to the 20- year battle won with the help of unleaded gasoline. ``Now we're on the verge of cleaning up carbon monoxide. We see pretty much that the problem is over.''

Emissions of lead - which posed health hazards to children who inadvertently gobbled it up while playing where it settled on streets and yards - have fallen 94 percent nationwide in the 20 years since the EPA started phasing in unleaded gasoline.

Similarly, new standards on vehicle manufacturers are steadily knocking down the amount of carbon monoxide emissions coming from cars, whose tailpipes account for 78 percent of all CO emissions in South Coast skies.

In 1972, cars were allowed to emit 39 grams of carbon monoxide a mile, but 1993 the standard was set at 3.2 grams. Today, many vehicles emit 1.7 grams, Jesson said.

The results mean many fewer tons of carbon monoxide are being spewed into the air. In 2000, Southern California measured 5,884 tons of CO emissions a day, including 4,583 from tailpipes. By 2005, the amount is expected to fall to 4,230 tons a day, with 2,967 from tailpipes.

The San Fernando Valley area has been relatively clear of carbon monoxide since 1997, when a violation was recorded in Reseda.

The South Coast basin as a whole remains out of compliance because of stubborn problems primarily in the Lynwood area south of downtown, where freeways and topography converge to lock in pollution.

What the region needs now are not the balmy days that draw newcomers when the rest of the country is buried under blankets of snow, but more whipped-up weather conditions that keep the air from being trapped and stagnant.

With no inversion layer, the carbon monoxide could rise and disperse instead of getting locked into the basin by rising warm air, experts said.

If the area logs one bad day, with a violation between now and Dec. 31, the region would have to start over next year, trying to go two consecutive years without a problem.

There is not likely to be any reprimand if the standard is not met this year because the region is working toward the goal, the EPA said.

``It'd be disappointing,'' Cassmassi said. ``We're members of the community as well. We live here; we want to chalk up another attainment. ... But we'd have to start over again.''

Carbon monoxide is only part of the group of air pollutants that combine to keep Southern California a smog capital.

The region faces a 2006 deadline to be rid of ozone - the main ingredient of smog that aggravates respiratory conditions like asthma - and a 2010 deadline to be done with particulate matter - tiny, inhalable particles of dust and pollutants.

Both goals will be difficult to reach, experts said.

``We're certainly looking at the 2006 particulate matter deadline as something that's going to be difficult to obtain. ... and the 2010 for ozone as difficult and challenging,'' said Jesson of the EPA.

Earlier this month, Denver, which a decade ago was famous for its brown cloud, became the first major city in the nation to achieve a clean bill of air health for five of the six standards.

The EPA measures carbon monoxide, ozone, particulate matter, lead, nitrogen dioxide - which the South Coast was rid of nearly a decade ago, the last area in the nation to meet that standard - and sulfur dioxide, which is not a problem for the South Coast region.

But the brown haze, which comes mainly from nitrogen dioxide, still settles over the South Coast region, despite that standard having been reached.

``An area like Denver really doesn't really have the challenge L.A. has. In the case of L.A., everything is wrong - meteorology, topography, continuous sunshine. ... You're basically cooking and accumulating more,'' Jesson said.

``You've got the most difficult problem anywhere in the country.''

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SOURCE: Daily News research