In the United States, 30 million citizens have problems with their lungs, and another 16 million have lung disease. Of these lung disease sufferers, 11 percent live in California.

Lung disease is currently the fourth leading cause of death, and it is rapidly increasing in its severity. There are several forms of lung disease, and they are all incurable, although society can prevent contraction of such disorders if it is willing to make an effort to decrease its causes.

The public most commonly associates lung disease with smoking, but smoking serves as only one of many causes. The American Lung Association states that air pollution control can also help reduce the number of lung disease cases. Pollution's particles invade and coat the lungs just as cigarette smoke blackens them and impairs function. The only difference is smokers choose to smoke but others subject us to pollution.

Gasoline- and diesel-powered cars and trucks, the most widely used modes of transportation, produce 40 percent of greenhouse gases. They emit harmful particulate matter, which creates a domino effect of problems: Pollution adds to global warming, so temperatures rise. Smog then gathers more readily, creating more respiratory infection and premature deaths.

Fortunately, the American Lung Association is taking action. It supports the California Air Resources Board's proposal to use a new standard for particle size. It will only permit particles less than 2.5 microns in diameter, rather than particles less than 10 microns in diameter. CARB claims that this new standard, if accepted, would result in fewer premature deaths, reduce the number of hospitalizations from other diseases, and decrease respiratory problem symptoms in California.

However, this change will not end problems altogether. A recent study showed that even exposure to smaller particles can cause cardiovascular problems. We must decrease the presence of all particulate matter. Carpooling, using public transportation, riding a bike, or walking can help accomplish this goal. However, these options have been available for a long time, and individuals do not seem to utilize them; they want a more feasible lifestyle change. Today, people can purchase a hybrid or an ultra low emissions vehicle, so the only change involves driving a different car.

Hybrid vehicles produce 50­70 percent less particulate matter than conventional diesel vehicles. This reduction helps the environment and citizens by decreasing pollution and the frequency of lung disease.

Hybrid vehicles are also more reasonable for the owner; they have 50 percent better fuel efficiency than SUVs and other trucks. Gas-guzzling automobiles may cost less than hybrid vehicles upfront, but the amount owners spend on fuel makes them more expensive in the long run. However, the popularity of the SUV causes Californians and other U.S. residents to ignore these costs. Californians bought more than 440,000 SUVs in 2002, and nationally 25 million SUVs have been sold.

To encourage consumers of their choice to buy hybrid vehicles, Los Gatos and other cities should offer incentives. Cities could create parking places for low-emissions vehicles only, similar to those for handicapped individuals. This would be particularly effective in crowded areas where parking is problematic. Other possibilities include allowing those with hybrid automobiles to use the carpool lane.

One incentive already in practice is a $2,000 tax deduction, which diminishes by $500 each year until reaching zero.

If cities motivate residents to buy fewer hazardous vehicles, and residents try to make a difference by contacting their city council or governor, change can start now ... with you.

Carolyn Penner, a 2003 graduate of Los Gatos High School, is a student at Stanford University and wrote this article for her human biology course.