Academic journal article Iranian Journal of Public Health

Personal Exposure to Polycyclic Aromatic Hydrocarbons in Newsagents in Tehran, Iran

Academic journal article Iranian Journal of Public Health

Personal Exposure to Polycyclic Aromatic Hydrocarbons in Newsagents in Tehran, Iran

Article excerpt

Introduction

One of the most significant current discussions in occupational health is the exposure to chemical agents in the outdoor environment. Polycyclic Aromatic Hydrocarbons (PAHs) are a group of organic compounds, which are found in the crude oil, mineral oil, and coal tar. These compounds are also produced during the incomplete combustion of fossil fuels and petroleum products (1, 2). PAHs can be emitted into the air from several industrial processes including aluminum electrolysis, foundries, and petroleum refineries (3). The other PAHs emission source is traffic emissions (4). PAHs exposure is the cause of many human cancers such as bladder, lung, and skin cancers (5). International Agency for Research on Cancer (IARC) has classified some of them in different categories such as benzo[a]pyrene in group 1 'known human carcinogens' and dibenzo[a,h]anthracene in group 2A 'probably carcinogenic to humans'. These compounds are considered as genotoxic and mutagenic and may have an effect on human immune system. PAHs have been identified as persistent organic pollutants since they are not readily biodegradable (6-8).

Emission of PAHs from vehicle exhaust is not the only source of exposure to these compounds in the urban atmosphere. Other sources of exposure include tire wear, asphalt particles, stationary combustion sources, furnace, power generation units, and petroleum refineries. Cigarette smoking increases PAHs concentrations in indoor environment (9, 10). The PAHs are present in the gaseous and particulate phases in the atmosphere. Low molecular weight compounds such as phenanthrene and anthracene are often present in the gas phase. Four ring PAHs such as fluoranthene, pyrene, and chrysene are distributed between the gas and particulate phases. Five and six rings PAHs including benzo[a]pyrene, benzo[a]anthracene, and dibenzoanthracene are present in the particulate phase in the atmosphere (4). The distributions of these compounds in the gas and particle phases depend on vapor pressure, air temperature, concentration and the amount of adsorbed PAHs on suspended particles (11, 12). Previous studies have reported increases in the PAHs concentration in indoor air and outdoor atmosphere (11, 13). The effect of the seasonal variations on PAHs concentration in outdoor atmosphere has been presented in many research projects (13). Moreover, the concentration of PAHs in winter is higher than that in summer and the existence of combustion source can induce an increase in the concentration of PAHs in indoor air (14). Benzo[a]pyrene was selected as an indicator for the classification of PAH compounds. A good correlation has been observed between the benzo[a]pyrene and other PAHs (15). However, little attention has been paid to assess personal exposure to PAHs found in urban atmosphere in workers occupationally exposed to these compounds (e.g., traffic police) or in a general population. Most studies have examined specific biomarkers as an indicator of exposure to PAHs in workers occupationally exposed to these compounds such as police officers, drivers, and newsagents but the existing research fail to provide accurate estimates from the breathing zone concentrations of PAHs (16).

Newsagents usually work close to heavy traffic flow and many hours a week. It is thought that this group of workers is the best representative of non-driver employees exposed to PAHs found in the urban air pollution. The mean exposure level of benzo[a]pyrene found in the urban air for nonsmoking newsagents was 1.00±0.32 ng/m3 during the cold period and 0.65±0.25 ng/m3 in the warm season. The annual average benzo[a]pyrene exposure for non-smoking newsagents was 0.82±0.33 ng/m3. That is to say, that high level of exposure to benzo[a]pyrene in these workers was reported (16). Occupational Safety and Health Administration (OSHA) has set a permissible exposure limit (PEL) of 0.2 mg/m3 for benzo[a]pyrene, anthracene, pyrene, chrysene, and phenanthrene and 10 mg/m3 for naphthalene (17). …

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