engleski

Comparison between PAH mass concentrations measured in PM10 and PM2.5 particle fractions

Polycyclic aromatic hydrocarbons (PAHs) widely distributed pollutants in the atmosphere are product of incomplete combustion of fossil fuels and other organic materials. Their sources include natural processes (forest fires and volcanic eruptions) and anthropogenic emissions (motor vehicles, industrial processes, domestic heating, tobacco smoke and other. They consist of two or more benzene rings. Most PAHs with fewer rings are gases, while those with more benzene rings bind to particles according to their affinity. Most of them are associated with fine airborne particles which can be taken into the bronhioles and alveoli of the lungs (Katz, 1980). It is generally accepted that PAHs associated with small particles (< 1 &#61510; m) tend to result from combustion or other high temperature sources whereas large particles (>10&#61510; m) are likely to arise from wind action on soils and deposited dust (Sheu, 1997). This property of PAH size distribution largely determines the degree of penetration of the respiratory system and so is related to human toxicity. Levels of PAHs concentration in the atmosphere depend on residental heating (coal, wood, oil), traffic density, type of industrial emissions, and tend to vary with season and meteorological conditions. More than 500 PAH have been identified in the air, but only 1-20 are measured (Lee, 1981). Several compounds of this group have been classified by the International Agency for Research and Cancer (IARC) as probable (2A) or possible (2B) human carcinogens (IARC, 1987). Many developed countries started to measure PAH concentrations in the atmosphere in the mid-20th century. Benzo-a-pyren (BaP) has been the most commonly measured PAH since it is always present, and this substance was used as an indicator of the carcinogenic hazard in environment pollution. The purpose of this investigation was to evaluate if there were statistically significant differences between PAH mass concentrations measured in inhalable or "thoracic" (PM10) and respirable or high-risk (PM2.5) particle fractions during two different seasons.

polyaromatic hydrocarbons; samples; air

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