Polycyclic aromatic hydrocarbons (known as PAHs) are products of incineration found in air pollution, vehicle exhaust (particularly diesel), tobacco, smoke and grilled foods. Exposures to PAHs, especially from vehicle exhaust and gasoline fumes, have been linked with increased incidence of breast cancer in both women and men.
A recent study in western New York examined air-monitoring records from 1959 to 1997 to establish PAH levels in residential areas. This case-control study of 3,200 women (ages 35 to 79 years) concluded that exposures to high levels of PAHs either at the time of their first menstrual period or at the time they first gave birth, were associated with an increased risk of post-menopausal breast cancer decades later.
Of course, dont smoke! And avoid being close to others who are smoking; second hand smoke is a major source of PAHs.
When purchasing a car, especially a used one, make sure that the emissions system meets or exceeds government standards. In particular, check that the computer system controlling the car's emissions is fully functional and that the catalytic converter works properly. (Also check out the most fuel-efficient 2009 cars and SUVs and the weirdest car fuels that could replace gas.)
Finally, PAHs are also found in the char of heavily grilled meats and fish. So when grilling, use a slower roast method, and scrape off any char that results from cooking.