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Each of us breathes 3,000 gallons of air a day, on average. Children breathe a little more than that, because of their fast metabolisms and habit of running around. We need oxygen to turn the food we eat into energy, and we need oxygen to simply stay alive. We depend on the air for our very vitality.

When I was a kid riding my bike through suburban Los Angeles, I took it for granted that if I pedaled too hard, I wouldn’t be able to breathe. I never connected it with the air quality. It was just the way the world was.

A lot has changed since then. Ever since the Clean Air Act passed in the 1970s, air pollution in American cities has steadily declined. Back then, Los Angeles exceeded ozone standards 175 days out of the year. Today it does on about 20.

The amount of carbon monoxide, particulate matter and lead in the air has gone down. So has the amount lead in the average American — there’s less than half as much lead in our bodies, on average, since leaded gasoline was phased out in the 1980s.

But research continues to link living near a power plant or a major roadway to adverse birth outcomes, diabetes, Alzheimer’s and cardiovascular disease, and most recently, autism. And as our health has improved in some ways, it’s decreased in others: The prevalence of asthma increased approximately 4 percent a year between 1980 and 1996, and has remained at a more or less constant high since then — at a point where approximately 8 percent of the U.S. population has asthma.

An increasingly probable culprit is diesel fuel, popular for its fuel efficiency and commonly used as the fuel in trucks and buses. When diesel burns, it releases particles that are much smaller than those produced by other fuels — so small that they can bypass normal respiratory defenses and remain in the lungs, causing them to become irritated and inflamed over time.

I was upset when I began to realize just how dangerous it is for both my health and the health of those around me to live near a popular truck route. It will take a much stricter version of the Clean Air Act to truly mitigate our exposure to diesel exhaust and other particulate matter that remains in the air. But until that day comes, I decided to focus on a few small things that would reduce both air pollution and my own exposure to it.

1. I began to take public transportation, walk or bike. If you live in San Francisco, you probably do this already.
 The next time I had to buy a car for work, I bought a hybrid.

2. I started eating locally produced foods — though of course “local” is a tricky concept. And so is giving up food. I stopped eating bananas, but couldn’t give up mangoes. My son refused to give up eating bananas entirely, which is fine. The boy needs his potassium.

3. I stopped having fires and barbecues. Getting rid of the grill has proved a lot harder. If I gave it to someone else, they would just grill on it, and the whole idea is to reduce the amount of soot in the air. So the grill has been sitting unused in the backyard for years now. Not a perfect solution.

4. I got serious about switching out the filters on my furnace every year, and made sure that my employer did, too. Most Californians just have the wall unit heaters, but those have filters, too. Replace it yourself or, if you have a landlord, make sure that they do it.

5. I bought a vacuum with a HEPA filter. No use in inhaling particulate matter twice — the first time when it enters your house through the air, the second when it’s kicked up by the action of vacuuming your carpet.

6. I decided to stay on the coast. The ocean air blowing in from the west means that San Francisco is a lot colder than Oakland or Berkeley, but it’s also not a place where particles tend to settle in the air and hang out.

7. This is related to six — be careful in choosing where you live. Take into consideration how close it is to trucking routes, especially if you have kids.

8. I got politically involved in air quality issues. Ultimately, all these little things that we do on our own add up. But legislation like the Clean Air Act remains the real game-changer.

The Clinic is an ongoing collaboration between the Program on Reproductive Health and the Environment at UCSF, Mission Loc@l and UC Berkeley’s Graduate School of Journalism. Prescriptions is a blog about health written by scientists at the Program on Reproductive Health and the Environment at UCSF.