COLUMN ONE : Particles--Tiny Killer in the Air : Less than half the thickness of a human hair, they go deep into the lung to cause illness and death. Despite new attention, the problem eludes solution.

Aaron Lee knows more about his bronchial tubes than most 11-year-olds. When he awakens at 3 a.m., struggling for breath in his Inglewood home, he gives himself a home breathing treatment--even though he sometimes falls back to sleep, spilling medicine on his pajamas.

Aaron, who has suffered from asthma for nine years, is among 100 children in the Los Angeles area helping researchers solve one of the thornier air quality mysteries of the 20th Century:

Why do microscopic particles in the air--a problem nationwide but most serious in Southern California--make respiratory illnesses worse? How do these particles, which are less than half the thickness of a human hair, kill?

Particulate pollution is a chemical grab bag that contains items as simple as desert sand when it is crushed into unseen powder by traffic, and as complex as the matter formed when chemicals in air pollution interact in Los Angeles.

As early as 1952, it was blamed for contributing to an estimated 4,000 deaths during a major fog episode in London. In the 1990s, it has been fingered by researchers as the culprit in as many as 60,000 deaths each year in the United States, 1,600 in the South Coast Air Basin.

Air quality officials throughout California are moving to deal with this confounding form of pollution, creating anxiety among builders and farmers at whom new regulations are aimed.

In the last three years more than a score of studies have linked non-crisis levels of the pollutants to increased respiratory and heart disease, school absenteeism, hospital visits, cancer in women and premature death.

Throughout the 1970s and ‘80s, ozone and other pollutants captured research money and scientific attention, diverting them from the study of particulates, which were mainly thought to mar visibility. Today, particulates are believed to be more damaging than ozone and are elbowing their way toward the top of a long list of particularly harmful pollutants.

But the limited understanding of particles and how they inflict physical damage has caused a gap in regulating killer dust and other forms of particulate pollution. Federal standards significantly more lax than those in California add to the question of just how strictly particulates need to be regulated.

In addition, particulate pollution is harder to control than ozone. It is not the direct result of manufacturing, but an indirect effect of human activities such as driving and construction.

Known as PM10--shorthand for particulate matter 10 microns in diameter or smaller--particulate pollution is small enough to be breathed deeply into the lungs’ most sensitive regions. In contrast, pollen ranges from 20 microns to 100 microns; it is big enough for the respiratory system to expel.

The first problem with particulate pollution is figuring out which forms are the most dangerous. Although the South Coast Air Quality Management District identifies seven major categories of particulate pollution, scientists are not certain which are the deadliest.

“There are hundreds and hundreds of different chemical constituents in this soup of stuff we call particulates,” said Veronica Kun, staff scientist for the Natural Resources Defense Council, an environmental organization. “We don’t really have very sophisticated ways of trying to figure out what’s in this particle stream.”

Fugitive dust--or dust particles of untraceable origin--is a major component, representing the greater part of particulate pollution in most Southern California areas. In downtown Los Angeles, 38% of particulate pollution is dust. In Anaheim, dust is about 34% of the problem. Road dust kicked up by traffic is the major culprit, with dust from construction sites coming in second.

In addition, the chemical reaction of gasses in the air, often egged on by sunlight, creates particles of nitrates and sulfates. Ammonium nitrates form about 38% of the mix in downtown Los Angeles and about 47% in Inland Empire cities such as Rubidoux and Upland. Like other particles when they reach the deep lung, ammonium nitrates are linked with lung scarring and irritation.

Another variety, sulfate particles, are a direct byproduct of diesel combustion and are in great supply in downtown Los Angeles and western Los Angeles County. “Microgram for microgram, diesel soot is the most hazardous of the long list of hazardous materials that are in PM10,” said John R. Holmes, director of research for the California Air Resources Board.

Others are not so sure. One camp argues that the chemicals carried by particles into the lungs cause the greatest harm. Others harbor suspicions that the particles themselves pose a threat.

“The health effects have not been adequately fleshed out,” said Robert Phalen, director of the air pollution health effects laboratory at UC Irvine and a particulate researcher.

Agencies Take Action

Although particulates are difficult to regulate, a host of government agencies are mounting efforts to cope with the problem. Within the month, the federal Environmental Protection Agency plans to upgrade five regions nationwide from “moderate” to “serious” violators of particulate pollution.

Although that will give the regions--Las Vegas, the Owens, Coachella and San Joaquin valleys and the South Coast Air Basin--longer than the rest of the country to fix their problems, it also will require stricter cleanup measures.

But the EPA has no plans to strengthen its particulate standards, said Barbara A. Bates, environmental scientist for the western region. The federal annual standard is 50 micrograms of fine particulates per cubic meter; the stricter California standard is 30 micrograms per cubic meter.

In California, ozone regulations from the Air Resources Board also have the indirect impact of lowering particulate pollution, particularly that caused by nitrates and sulfates. But many of those rules have yet to take full effect.

“It’s not a problem that’s being ignored,” said Bill Sessa, ARB spokesman. “But it’s a thorny one. On the one hand, a large part of the particles in the air are related to what we’re already addressing. The more perplexing part is fugitive dust.”

In the San Joaquin Valley, the regional air quality district is considering a series of “no-till” days that will stop dust-making farm activities when there are high winds. The Owens Valley is experimenting on solutions for the problem caused when Owens Lake largely went dry because its water source was diverted to Los Angeles.

To much construction industry complaint, the AQMD passed a fugitive dust ruling last month to control dust created in large part by building. Construction companies, among other things, must stabilize graded areas with water or chemicals during high winds. In addition, the AQMD is working with Coachella Valley’s nine cities to get ordinances passed to place even stricter dust controls on construction.

No one is certain who is most at risk from particles’ airborne threat. Ozone, a major component of smog, can cause respiratory problems and shortness of breath and does its greatest harm to children, the elderly, exercisers and those who work outdoors.

“But with particles, it might be a more general range of the population that is at risk,” said Bart Ostro, chief of the Air Pollution Epidemiology Unit for an agency within the California Environmental Protection Agency. “Certainly, the greater people at risk have pre-existing, chronic respiratory problems. Even healthy people are at risk.”

Fine particles remain suspended in the air for long periods of time. Because they settle so slowly, they can travel more than 100 miles before coming to rest, exposing large numbers of people and allowing them to sneak past the nasal passages and throat--the first line of respiratory defense.

London in December, 1952, provided the most dramatic early example of the powers of particulate pollution--along with the beginnings of a data trail resulting in today’s stricter controls.

The city was enveloped in a thick fog laden with coal dust. “Visibility was cut to 10 feet,” said Dr. David Bates, medical professor emeritus at the University of British Columbia and a chest doctor at a London clinic during the crisis. “All traffic came to a standstill.”

In his clinic, which treated chronic lung diseases, Bates said patients arrived in droves during the pollution episode, plagued with severe attacks of their long-term respiratory ailments.

“What we didn’t realize was that a lot of people were dying at home, on the way to the hospital,” he said.

Patients showed up with pneumonia, heart disease, chronic obstructive lung disease--problems that proved fatal. In addition, deaths in children under age 5 had increased.

The air in Los Angeles is a far cry from London 40 years ago. However, the city violates federal annual standards for particulate pollution 40% of the year, according to the AQMD; the Inland Empire is in violation 70% of the time.

But it is the constant elevated level of fine particles found in the South Coast Air Basin, Coachella Valley, San Joaquin Valley and areas outside the state that concerns researchers as much as the crises or clear violations.

“At levels below the federal standard . . . particles are associated with substantial health effects,” said C. Arden Pope, an environmental economist who has studied particulate pollution in Utah and is a visiting scientist at the Harvard School of Public Health. “Long-term exposure to these elevated pollution levels may be very important.”

Particulate pollution has been researched in some fashion since the London crisis, with studies during the 1970s and ‘80s pointing to increasingly strong links between the pollutants, death and disease--particularly the work of epidemiologist Joel Schwartz with the EPA.

But fine particulate pollution was not monitored in most places throughout the country until the EPA demanded it in 1987. Even now, most areas in the United States only monitor it every six days.

“It wasn’t until the last few years that the evidence became compelling” that particulate pollution was a direct cause of death and disease, Pope said. “I didn’t even believe it until 1988. That’s when I started seeing big effects in my data.”

Pope’s work looked at the Utah Valley, where a steel mill, the largest polluter in the area, belched large quantities of sulfates. A labor dispute closed the mill for 13 months. Pope, along with other researchers, gathered data for the three years before, during and after the closure.

His research, published between 1989 and 1992, showed that when particulate pollution levels rose 100 micrograms per cubic meter, the death rate rose 16%, a jump “that’s so big I don’t like to say it.” When the steel mill was open, there were twice as many children in the hospital for bronchitis and asthma as when the mill was closed. On high pollution days, school absences rose 40%.

During the same period, analyses of data from several cities by the EPA’s Schwartz indicated that as many as 60,000 people died in the United States each year from breathing particulates at or below legally allowed levels. The researchers correlated high particulate levels with increased mortality after determining no other factors could account for the premature deaths.

Although 23 studies on particulate pollution have been published since 1989, none has unlocked the mystery of why the tiny specks are so dangerous.

UC Irvine researchers, studying whether road dust impairs the lungs’ defense mechanisms in rats, believe that they may be close to at least beginning to unravel the mystery. One defense mechanism is the macrophage, a cell in the lung that engulfs foreign materials and secretes a toxic chemical to destroy the invaders.

The study seems to indicate that road dust harms the macrophages, perhaps killing them and making them spew their toxics directly into the lung, harming human tissue.

“We don’t suspect the harm will be great enough to cause progressive, massive lung disease,” Phalen said. “But we suspect the harm to these cells will be great enough to diminish their ability to kill foreign organisms.”

More Data Collected

The Coachella Valley, home of tony resort towns such as Palm Desert and Rancho Mirage, is adding to the growing body of information. Trying to balance its image as a playground for the golf and tennis set with its nagging dust difficulties, it has become a laboratory for particulate research and control.

The region, which sees hourly particulate levels as high as 999 micrograms per cubic meter, has daily particulate data for the past 2 1/2 years. A health study is in the works to analyze pollution levels, hospital admissions and death statistics. Demonstration projects to show construction companies the benefits of chemical stabilizers and interim planting on construction sites have been conducted. And the AQMD is planning a first-ever warning system for the area to be patterned after smog alerts.

But the construction industry contends that sufficient health studies have yet to be done. Its representatives say increased regulations will cost jobs.

“The building industry in no way wants to lead people to believe they don’t understand there’s a problem with dust,” said Ed Kibbey, executive director of the Building Industry Assn.’s Desert Council. “But the South Coast Air Quality Management District has heaped most of the responsibility on the building industry.”

Still, Emily Nelson, chairwoman of the Coachella Valley’s particulate pollution working group, is adamant about protecting the region’s health. “We have to protect the community,” Nelson said. “You can’t wait to count the bodies before you go out and try to control this.”

Yet another piece of the particulate puzzle is being provided by Aaron Lee and other Los Angeles children with asthma. Between August and October, the children took daily tests of their lung function, recorded whether they stayed home from school or went to the doctor, sneezed, wheezed, coughed or gasped.

In exchange for gift certificates, they mailed their diaries to the Los Angeles Children’s Asthma Project, which is studying whether the environment--including weather and particulate pollution--worsens asthma. The study used only African-American children because African-Americans have three times more hospitalizations for asthma than whites, although no one is certain why.

Ostro, who is directing the study for Cal/EPA, says it is too soon to determine the effects of the environment on the children. But some young subjects have strong views on what ails them.

Aaron’s asthma is triggered by a variety of factors, including dust, mold, pollen, dogs and air pollution. Pollution, Aaron said, “does more than just dirty up the planet. It triggers sicknesses like asthma.” And it makes him sick more than ever.

“Nature can’t help it,” he said. “But humans can stop pollution. We have control over it. . . . If you notice it, I think you should do something about it.”

Dust to Dust

Nearly the entire area governed by the South Coast Air Quality Management District violates state particulate pollution standards at least some of the time. This map shows the number of days in 1990, the most recent year for which figures are available, that regions of the Southland exceeded the state daily standard of 50 micrograms of fine particles per cubic meter.

Pollution Level

Last Oct. 2, Indio had the kind of day that is tailor-made for a particulate pollution warning. The culprit was the strong wind in the Coachella Valley. The state daily standard for fine particle pollution is 50 micrograms per cubic meter; the federal is 150.

Source: South Coast Air Quality Management District