What are Polycyclic Aromatic Hydrocarbons?
Polycyclic Aromatic Hydrocarbons (PAHs) are a group of chemicals that occur naturally in coal, crude oil and gasoline. PAHs also are present in products made from fossil fuels, such as coal-tar pitch, creosote and asphalt. When coal is converted to natural gas, PAHs can be released. Therefore, some former coal-gasification sites may have elevated levels of PAHs. PAHs also can be released into the air during the incomplete burning of fossil fuels and garbage. The less efficient the burning process, the more PAHs are given off. Forest fires and volcanoes can produce PAHs naturally.
Although hundreds of PAHs exist, two of the more common ones are benzo(a)pyrene and naphthalene.
How can I be exposed to PAHs?
PAHs are found throughout the environment in the air, water and soil, and can remain in the environment for months or years. Levels of PAHs in urban air may be 10 times greater than those found in rural areas. You also may be exposed to PAHs in soil near hazardous waste sites or near areas where coal, wood, gasoline or other products have been burned. Some water supplies in the United States have been found to have low levels of PAHs.
In the home, PAHs are present in tobacco smoke, smoke from wood burning stoves and fireplaces, creosote-treated wood products and some foods. Barbecuing, smoking or charring food over a fire greatly increases the amount of PAHs in the food. Other foods that may contain low levels of PAHs include roasted coffee, roasted peanuts, refined vegetable oil, grains, vegetables and fruits. A variety of cosmetics and shampoos are made with coal tar and therefore may contain PAHs. The PAH compound naphthalene is present in some mothballs and cleaners.
How can PAHs affect my health?
The health effects that can be caused by exposure to PAHs depend on:
It is not clear whether PAHs cause short-term health effects. Other chemicals commonly found with PAHs may be the cause of short-term symptoms such as eye irritation, nausea, vomiting, diarrhea and confusion.
Possible long-term health effects caused by exposure to PAHs may include cataracts, kidney and liver damage and jaundice. Repeated skin contact with the PAH naphthalene (found in some mothballs) can result in skin redness and irritation. Breathing or swallowing large amounts of naphthalene can cause the breakdown of red blood cells.
Some people who have breathed or touched mixtures of PAHs and other chemicals for long periods of time have developed cancer. Some PAHs have caused cancer in laboratory animals when they breathed air containing them, ingested them in food or had them applied to their skin.
How can I reduce my exposure to PAHs?
One of the greatest sources of exposure to PAHs is breathing these chemicals in tobacco smoke. Smokers can lower their own exposure and the exposure of their families by stopping smoking. Additional steps to lower exposure to PAHs include:
What can medical tests tell me about my exposure to PAHs?
Tests are available to measure the presence of PAHs in blood or urine. These tests cannot be used to predict possible health effects, but can only show that you have been exposed to PAHs. These tests are not routinely available at a doctor's office because they require special equipment. Some hospitals can provide this testing. If you think you might be ill from exposure to PAHs, contact your doctor.
Where can I get more information?
Illinois Department of Public Health
This fact sheet was supported in part by funds from the Comprehensive Environmental Response, Compensation, and Liability Act trust fund through a cooperative agreement with the Agency for Toxic Substances and Disease Registry, Public Health Service, U.S. Department of Health and Human Services.
Updated February 2009
of Public Health
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Springfield, Illinois 62761
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