Ah, summer. Season of sizzling heat, fiery sunsets and jasmine scent wafting in the night air. Season of ozone buffeting gently in the breeze.
Flying home--from vacation, perhaps--you watch through the window as the sprawling Southland rolls into view, cloaked in a rusty, hazy shroud of nastiness--which you breathe, it occurs to you afresh, every day.
True, the smog has gotten much better down the years since its zenith in the 1950s, thanks to aggressive emissions control. But our air is still the worst in the nation. Hundreds of times a day, we drag it into our lungs. Hundreds of times our children drag it, too, into their own mini-lungs.
We're talking ozone. Carbon monoxide. Sundry oxides of nitrogen and a smorgasbord of carcinogens, the whole brew heavily peppered with teeny-tiny particles that originated anywhere from that fume-spewing bus in front of you to that burger Aunt Millie grilled you on her barbecue.
Are we out of our minds to even be inhaling? And what--short of packing up and bailing L.A.--can we do to lower our exposure and our risk?
The Situation Has Been Worse
First, by way of some perspective: We're not experiencing anything like the 1952 episode in London, when you couldn't see 10 yards in front of you and 5,000 people died in roughly a week from the dense smog caused by coal smoke. And there are plenty of other things we do, such as eat poorly and smoke heavily, that harm us more, experts say.
"I've heard people say that living in L.A. is like smoking a pack a day--clearly, that's nonsense," says Dr. John Peters, professor of preventive medicine at the USC School of Medicine. But risk--and risk we didn't sign up for--is still there. "Whether it's like smoking one cigarette a day, half a cigarette a day, a tenth a day--we don't know," Peters says.
On the one hand, there's strong evidence that smog can and does kill, that it can cause other ill effects such as inflamed lungs and loss of lung capacity, scientists say. The elderly, the infirm, children, people with breathing disorders like asthma, and those with heart disease seem particularly at risk. But it's unclear how many people are suffering, or what the long-term effects are of breathing in polluted air for decades.
"These are the questions," Peters says, "that everybody wishes they had answers to."
Scientists are beginning to provide some of those answers. Studies in various smoggy cities around the world are telling us more and more about the biological effects of smog. In Southern California, a large smog study is monitoring long-term health effects in thousands of children. And researchers are using new sophisticated smog-gathering equipment that collects and concentrates dirty air direct from our cities allowing them to study the health effects of polluted air more realistically than ever before.
Already, there have been surprises. Scientists used to think ozone was the most worrisome air pollutant for Angelenos.
Particle Pollution a Serious Hazard
"Today, scientists are increasingly finding that particle pollution is as much or more of a health problem than the ozone," says Bill Kelly, spokesman for the South Coast Air Quality Management District. This goes especially for the smallest particles, especially the ones spewed out in diesel exhaust.
Air pollution has always been kind of a feature of the Los Angeles basin: Hundreds of years ago, the region was known as the Valley of Smokes, because the fires of the Native Americans hugged the ground instead of rising and blowing away.
L.A.'s famous "inversion layer" is the cause: Warm air tumbling over the mountains traps colder air beneath it. The fumes from all those cars, trucks and factories stay in that lower, colder layer, around us.
What's in that heady mix? Ozone, which is great when it's up in the stratosphere but is definitely undesirable down here. Back in the 1950s, a Caltech chemist--who was studying the chemistry of pineapple flavor at the time--figured out how ozone was made: from sunlight, a motley mix of "volatile organic chemicals" (things like gasoline, paints, solvents and even chemicals from some trees) and chemicals called nitrogen oxides (from vehicle exhaust and power plants).
Scientists have done hundreds of studies on ozone's health effects: on people exercising in labs, kids running around at summer camps, on adults jogging, hiking or picking raspberries in polluted areas. The bottom line? Ozone, a very reactive chemical, inflames the walls of our bronchial tubes and lungs. Even in healthy people, lung function is temporarily reduced, especially when we're exerting ourselves. You can get chest pains or coughs. It takes hours for lung function to recover.
High ozone levels have also been linked to increased hospital visits, especially for people who already have lungs compromised from asthma, emphysema or bronchitis.
Nitrogen dioxide--which gives our air its distinctive red-brown hue--is another smog ingredient. It not only helps form ozone, but also is nasty in its own right, irritating the lungs and--in a big ongoing study of 3,600 Southland schoolkids--appears to be linked to wheezing attacks.
Study Monitoring Effects on Kids
This landmark study, headed by USC's Peters, should help sort out what's bad and baddest about the air we breathe, and what the exposure means to our children's health long term. Twelve stations scattered through the Southland are monitoring smog ingredients hourly. Each site--including ones in Long Beach, Lake Arrowhead, Atascadero, Upland and San Dimas--has a different kind of air quality--this one high in ozone, that one high in particles, for example. From 1993 through 2003, the kids are being monitored for their breathing capacity, for health problems and for sickness-related absences from school.
The wheezing result is from the first year of the study and is surprising for several reasons, says Peters, who heads this effort. Not only were nitrogen dioxide and acid vapor more strongly linked to wheezing than was ozone, but the finding was detected only in boys. Girls, meanwhile, showed up with lower lung capacity in areas rich in nitrogen dioxide and fine particles.
Peters says he's not convinced the sex difference will hold up over time--it could just be a statistical fluke. In any case, he says, there's a lot more data to be gleaned before anyone knows what's happening to the growth and health of all these children's lungs.
Fine particles could well be doing bad things. Smog scientists are increasingly worried about these tiny specks, which come from all over--from car exhaust, ground-up tires, wood smoke, wind-borne dust, salt and more--and in all kinds of sizes. Studies all over the world link modest increases in particle levels to increased hospital admission rates as well as death rates that jump by 1% to 5%, mostly for older people with preexisting lung or heart conditions.
The heart disease deaths are especially mysterious, experts say. Possibly, breathing particles affects the beating of the heart: In experiments they make dogs' hearts beat more irregularly, as well as those of elderly people.
"But the bottom line is, nobody knows why these people are dying," says Dr. John Balmes, professor of medicine at UC San Francisco.
Answers should come easier now that air pollution scientists can work in the lab with real-smog samples from our cities. In the past, they've always had to rely on particles they created themselves, which didn't match the complexity of the brew we actually breathe.
Small Particles the Most Worrisome
Whatever the mechanism, air quality experts are particularly concerned about the smallest kinds of particles, especially ones pouring from trucks and other diesel fuel-burning vehicles. They suspect that these particles, as well as other known carcinogens in the air, may raise our lung cancer risk--though the link between smog and cancer is still unclear.
And the list of pollutants goes on: carbon monoxide, a smorgasbord of acids, mixtures of chemicals that make our eyes sting--holy moley. We can't escape the smog if we live in the L.A. area, but there are things we can do to help our health, experts say--and which might be particularly important for people with lung conditions, like asthma, or heart disease.
* First off, parents of children with asthma should be sure that they and their baby-sitters are well-educated about the child's condition, medications, and when to administer them.
* All of us should eat a diet rich in fruits and veggies, and consider supplementing with multivitamins and/or vitamin C. For smog? That's right. The body deals better with environmental onslaughts if it's good and feisty, and chemicals like ozone irritate lungs because they're highly reactive oxidants. Dietary antioxidants may help, but don't go nuts on the supplements.
* Masks--those you can find at home improvement centers--probably won't do much. But staying indoors in an air-conditioned house can help on particularly smoggy days--unless your inside is dirtier than your outside, from mold, dust or tobacco. (Gas cooking produces nitrogen oxides: Use your vent!)
* It's healthier (except on the pocketbook) to live near the ocean, and away from busy roads. And you can certainly choose when and where to exercise. Ozone forms throughout the day, traveling east, along with particles, on the ocean breeze. Live inland? Consider exercising in the morning. Wherever you live, avoid exercising near heavy traffic.
* Finally, you can limit your risk by spending less time in the very thing that causes so much of the problem to begin with--the car. A recent study reported that levels of many dangerous pollutants from tailpipe emissions are particularly high inside cars. Keep driving to a minimum, especially in the rush hour, use car pool lanes (cars aren't packed so tight, so the air's cleaner) and try not to get stuck behind one of those awful, smelly diesel trucks.
Keep breathing--and have a happy summer.