Polycyclic Aromatic Hydrocarbons
www.health.state.mn.us/divs/eh/children/faqs.htmlWhat are Polycyclic Aromatic Hyrdocarbons (PAHs)?
How can PAHs affect children's health?
How might children be exposed to PAHs?
How can I reduce my child's exposure to PAHs?
What are Polycyclic Aromatic Hyrdocarbons (PAHs)? Polycyclic Aromatic Hydrocarbons (PAHs) are a group of chemicals formed by incomplete combustion of organic materials, such as fossil fuels, municipal and industrial waste, wood, tobacco, and meat. Large quantities of PAHs are released during such natural events as volcanic eruptions and forest fires. However, many human activities, such as burning coal, oil, and wood for heat and gas-powered motor travel, also release PAHs into the environment. Grilling food and smoking also create PAHs, albeit in smaller quantities. PAHs are found in asphalt, creosote, coal tar pitch, roofing tar, coal, and crude oil. A few PAHs are used in medicines, plastics, dyes, and pesticides. PAHs generally occur as complex mixtures of chemicals.
How can PAHs affect children's health?
Of the more than 100 chemicals classified as PAHs, only a few have been subject to intensive scientific study. While it is difficult to generalize about this broad range of chemicals, it is certain that some PAHs, either individually or in mixtures with others, can cause adverse health effects. Whether other PAHs may have any impact on health and, if so, the nature of that impact, is largely unknown.
Some PAHs have the ability to cause cellular mutations and are considered carcinogenic. Inhalation of high levels of PAHs in occupational settings has been shown to cause respiratory effects and immune system depression in humans. Mixtures of PAHs can cause skin disorders in humans. In laboratory studies, some PAHs have also been shown to cause developmental effects and changes in kidney and liver functioning. While these effects have not been reported for humans, it is safest to assume that some adverse effects may be possible and to try to reduce exposures. As with exposure to any chemical, health effects resulting from exposure to PAHs will depend on the duration and frequency of exposure, as well as the quantity of the PAH present, and whether exposure occurs by inhalation, ingestion, or dermal contact.
Benzo(a)pyrene is one PAH which has been studied extensively. This PAH is considered a potent carcinogen, meaning low doses may cause cancer. The toxicities of other, less potent, PAHs are commonly evaluated relative to benzo(a)pyrene.
How might children be exposed to PAHs?
Many natural events and human activities produce PAHs. Consequently, PAHs are found throughout the environment in water, soil, and air. Exposure is most likely to result from PAHs present in air, either as vapors or attached to dust or other particles. Although PAHs can travel long distances in the environment, concentrations of PAHs in air will be higher near PAH sources, such as areas of traffic congestion, waste incineration, asphalt roads, and residential wood burning. In the home, sources of exposure are secondhand smoke, wood fire smoke, and food. While many foods typically contain low levels of PAHs, foods that have been grilled, charred, or otherwise cooked at high temperatures contain higher levels of PAHs. Generally, exposure will be to a mixture of PAHs rather than to a single PAH.
How can I reduce my child's exposure to PAHs? Since PAHs are found throughout the environment, it is difficult to avoid exposure. However, you can significantly reduce your child's exposure by avoiding certain areas and by modifying some home and recreational activities. The following are practical and easy steps you can follow to reduce PAH exposure.
Avoid smoke from wood fires, whether from home heating or for recreational purposes.
Avoid exposure to automobile exhaust and areas of high traffic congestion.
Avoid areas where asphalt road construction or tar roofing is occurring.
If you smoke, smoke outdoors and in areas away from children. Avoid areas where your child may be exposed to secondhand smoke.
Prepare foods by slower cooking over low heat, rather than by charring or grilling food.
Avoid skin contact with soot.