Most commonly, PAHs are released into the air when fossil fuels, gasoline and garbage are burned, but other routes of exposures -- such as eating charbroiled and smoked foods -- also exist.
How You Can be Exposed to PAHs
Perhaps the most common route of exposure to these chemicals is by breathing contaminated air. PAHs exist in cigarette smoke, wood smoke, vehicle exhaust, diesel exhaust and asphalt roads, as well as in the air of industrial coking, coal-tar and asphalt production facilities, along with trash-incinerating facilities.Because of this, air in urban areas may have PAH levels 10 times higher than those in rural areas. 
PAHs are also created when meats are barbecued, smoked or charbroiled. Other foods, including roasted coffee, roasted peanuts, refined vegetable oils and any food grown in PAH-contaminated soil (such as near a hazardous waste site) may also contain the chemicals, as can processed and pickled foods. Polycyclic aromatic hydrocarbons can also contaminate soil and water supplies, and certain areas in the United States have shown low-level PAHs in their water. The compounds are so widespread that simply coming into contact with air, water or soil around a hazardous waste site can increase your exposure.Finally, PAHs are used in certain cosmetics, shampoos and hair dyes (anything that contains coal tar), and you may absorb some of the chemicals if you use these products. They're also present in certain household products, including creosote-treated wood and mothballs,
Health Risks of Polycyclic Aromatic Hydrocarbons
PAHs are capable of causing serious problems for humans and animals. They are "reasonably expected to be carcinogens,"
according to the Department of Health and Human Services, and have also been found to cause reproductive and developmental harm.
For instance, mice fed high levels of a PAH during pregnancy had problems reproducing, as did their offspring. The offspring also had higher rates of birth defects and lower body weights.
Exposure to PAHs over time has been linked to cataracts, kidney and liver damage and jaundice in humans, and animal studies have shown the chemicals to harm the skin, body fluids and the body's ability to fight disease.
It's also known that people who have breathed or touched PAHs over time have developed cancer, and animals that breathed the chemicals developed lung cancer, while those that ate them got stomach cancer and those that had them applied to their skin got skin cancer.
How to Best Reduce Your Exposure to PAHs
Because PAHs are ubiquitous in the environment (they're even found in house dust) you probably can't eliminate your exposure, but you can certainly cut it down with these tips from the Illinois Department of Public Health:
- Quit smoking if you do, and try not to be around second-hand tobacco smoke
- Cut back on, or eliminate, charbroiled, smoked and barbecued foods from your diet
- Reduce your use of wood-burning stoves and fireplaces
- Don't use cosmetics, shampoos and hair dyes that contain coal tar
- Don't use mothballs, moth flakes or deodorant cakes (try cedar shavings or aromatic herbs instead)
- Avoid skin contact with creosote-treated wood products (wear gloves, long pants and long sleeves when handling them)
Source: www.SixWise.com

ohh nice information
There are couple of posts on Science and Society about PAHs you may be unterested
1. http://giri25.blogspot.com/2008/02/polycyclic-aromatic-hydrocarbons-1.html
2. http://giri25.blogspot.com/2008/03/polycyclic-aromatic-hydrocarbons-2.html
Dear Basanta
Many thinks for this.. cool. In fact our group is looking for the uses of PAHs in material science.Recently these compounds are under study for the uses: as Oleds material, semiconductor and many more in many laboratories.
But it is dangerous of course.
Thanks for your information. keep on reading this blog.
Anyway good information.
Keep on updating new informations.
thanks ..keep up reading blod
Shall we enjoy barbiq again?????????
you should be conscious for health. Making jock again ...that ... planning for barbecue... beware of PAHs... its dangerous....
Here is a discussion forum on PAH and particle pollution. Please join us!
http://burningissues.org/forum/phpBB2/index.php