Atmospheric polycyclic aromatic hydrocarbons (PAHs) in Asia: A review from 1999 to 2004
Introduction
This review study summarizes the emission characteristics, sources, sampling and analysis methods of polycyclic aromatic hydrocarbons (PAHs) in the Asian countries Thailand, Malaysia, China, Korea, Japan and Taiwan. Although these countries have similar atmospheric conditions—quite sunny and mild—the intensity of traffic, energy consumption and energy generation vary widely (Mastral et al., 2003).
PAHs are formed from the incomplete combustion or pyrolysis of organic material such as oil, petroleum gas, coal, and wood, which are usually used in energy production. Tobacco smoking also increases the ambient levels of PAHs in air, and the use of heating devices can increase the concentrations of PAHs indoors (WHO, 1987). PAHs have attracted much attention in the studies on air pollution recently because some of them are highly carcinogenic or mutagenic. In particular, benzo[a]pyrene (BaP) has been identified as a highly carcinogenic compound. Reliable sampling and analytical methods are necessary to measure the extent of human exposure to Bap and other PAHs (US EPA, 1999). Although atmospheric PAHs can be present in particulate or gaseous matters, they are associated predominantly with particulate matters. Particle-bond PAHs (p-PAHs) are considered to be the most hazardous substances to human health. From the view of this health concern, monitoring the levels of p-PAHs in urban areas is very important (Chetwittachan et al., 2002). The highest concentrations of atmospheric PAHs are usually found in urban areas due to the increasing vehicular traffic and the scarce dispersions of atmospheric pollutants. The risk associated with human exposure to atmospheric PAHs is highest in the urban because of the density of population (Caricchia et al., 1999). Despite the drastic reduction of urban particulate pollution in cities caused by the burning of coal and a shift toward other fossil fuels (oil or natural gas) for domestic heating, the increasing population and traffic have all contributed to the gradually more serious particulate pollution in the cities. In addition, particles produced by cars are much smaller than coal particles and are found in the breathable size fraction (Manoli et al., 2002). Most studies have provided more information on the multi-ringed heavier PAHs rather than the lighter ones. These lighter PAH compounds have less carcinogenic or mutagenic properties; however, they are most abundant in the urban atmosphere and react with other pollutants to form more toxic derivatives (Park et al., 2002).
The concentrations of the following PAHs were studied and their elution orders in GC/MS analyses follow the sequences of naphthalene (Nap, m/z 128), acenaphthylene (AcPy, m/z 152), acenaphthene (Acp, m/z 154), fluorene (Flu, m/z 166), phenanthrene (PA, m/z 178), anthracene (Ant, m/z 178), fluoranthene (FL, m/z 202), pyrene (Pyr, m/z 202), cyclopenta[c,d]pyrene (CYC, m/z 226), benzo[a]anthracene (BaA, m/z 228), chrysene (CHR, m/z 228), benzo[b]fluoranthene (BbF, m/z 252), benzo[k]fluoranthene (BkF, m/z 252), benzo[e]pyrene (BeP, m/z 252), benzo[a]pyrene (BaP, m/z 252), perylene (PER, m/z 252), indeno[1,2,3,-cd]pyrene (IND, m/z 276), dibenzo[a,h]anthracene (DBA, m/z 278), benzo[b]chrycene (BbC, m/z 278), benzo[g,h,i]perylene (BghiP, m/z 276) and coronene (COR, m/z 300) (Fang et al., 2004a, Fang et al., 2004b).
In the past, chimney sweeps suffered from skin cancers and scrotal cancers due to higher dermal exposure in the PAH compounds. Epidemiological studies have been conducted among workers exposed at coke ovens in coal coking, coal gasification, asphalt, foundries, and aluminum production plants. Workers who are exposed to diesel exhaust have also been investigated (Partanen and Boffetta, 1994, Costantino et al., 1995). People in all listed occupations are also exposed to other chemicals, making a direct correlation between increased levels of PAHs and lung cancer problematic. Only a few animal tests have addressed the ingestions of PAHs. BaA, BaP, DBA, and mixtures of PAHs (coal tar) were carcinogenic (WHO, 1998). Some of the PAH species are known to be animal and/or human carcinogens, so evaluating the healthy risk that is associated with the exposure to both particulate PAHs and gaseous PAHs is important. Gaseous PAHs usually contain more fractions of less carcinogenicity and lower molecular weights, while particulate PAHs contain more fractions of higher carcinogenicity and higher molecular weights. In principle, PAHs with high molecular weights are often more carcinogenic than those with low molecular weights (Park et al., 2002, Tsai et al., 2002). With these biochemical and carcinogenic properties of PAHs, the PAHs present in surrounding air have direct impacts on human population. For example, mortality due to lung cancer is increasing in developed countries. Thus, a survey of PAHs levels in indoor and outdoor air is an important as a part of risk assessment and management associated with these chemicals (Liu et al., 2001).
In 1987, the U.S. Environmental Protection Agency (EPA) promulgated a new size-specific air quality standard for environmental particulate matter (US EPA, 1999). This new standard applies only to particles with aerodynamic diameters of smaller than or equal to 10 μm (PM10) and replaces the original standard for the total suspended particles (TSP). PM2.5 and aerosols with a diameter of 1.0 μm or less are now being taken into consideration because these particles can be inhaled into the deeper respiratory tract regions. Moreover, PAHs are concentrated in the submicron particulate matter by the condensations of gaseous PAHs. Many problems affect the samplings and measurements of atmospheric PAHs:
- (a)
PAHs are emitted in a very complex matrix;
- (b)
Many studies cannot be compared because different analytic techniques caused different results. PAHs with very low concentrations can only be detected using highly sensitive analytical methods which are not suitable for larger quantities and vice versa;
- (c)
Most approaches to atmospheric PAHs sampling use filters and adsorbents to catch particular and gaseous PAHs, which are not suitable for the other volatile species; also, other species cannot be completely extracted once adsorbed;
- (d)
PAHs deposition with the PM greater than 3–5 μm and/or gaseous PAHs re-volatilization may follow deposited;
- (e)
strong influences of the meteorological conditions;
- (f)
strong influences of the ambient contaminants;
- (g)
others.
This work attempts to discuss the atmospheric PAH data from Asia to help understand the sources, distributions of PAH species and the impact of atmospheric PAH on health in Asian countries.
Section snippets
Thailand
Total suspended particle concentrations were sampled by high-volume samplers (HVC-1000, Shibata, Japan and Precision Scientific Co., USA). The total PAH content of the atmospheric suspended particles was extracted using dichloromethane (DCM) and analyzed by GC-FID analysis. The analytical method was developed based on the US EPA method TO-13 (US EPA, 1999). The sampling site was the Asian Institute of Technology, west of the Phahonyothin road, which is the main artery between the north and
Malaysia
Aerosol samples were collected in six cities in Malaysia to investigate the influence of forest fires in Indonesia. Six forest-fire smoke haze and two non-haze particulate samples were collected by high-volume samplers. The individual PAH content in atmospheric particles was analyzed by GC/MS. The δC13 of PAH was also monitored by gas chromatography/combustion/isotope-ratio-monitoring mass spectrometry (GC/C/IRMS). The results of ambient particulate PAH content and δC13 of PAHs in Malaysia
China
Cooking is a major source of indoor PAHs in China. Indoor air PAH sources, such as kitchens, were studied. The concentrations of 12 PAHs in the air of six domestic kitchens and four commercial kitchens in China were measured during 1999–2000. The average concentration of total PAH in commercial kitchens was 17 ng/m3, comprising mainly of 3- and 4-ring PAHs, and 7.6 ng/m3 in domestic kitchens, dominated by 2- and 3-ring PAHs and especially naphthalene. The BaP levels in domestic kitchens were
Korea
Bae et al. (2002) measured the PAH size distribution and the dry deposition in four cities (Seoul, Inchon, Yangsuri and Yangpyoung) in Korea. The size distributions were measured using a cascade impactor and the extent of dry deposition was measured using a dry deposition plate. The PAH size distribution and dry deposition were obtained by soxhlet extraction with a mixture of dichloromethane and petroleum ether and analyzed by GC/MS. The total particulate PAH concentrations are between 22.9 and
Japan
Three Kimotodenshi HV-120 high-volume air samplers with 2500 QAT-UP filters at a flow rate of 1.5 m3/min were used to collect airborne particles at three sites in Kanazawa city, Japan. Samples were extracted by 30 ml benzene-ethanol (3:1), and washed with 60 ml of 5% sodium hydroxide, 60 ml of 20% sulfuric acid and 60 ml of water. Particulate PAHs (BaP and pyrene) were analyzed by HPLC system with chemiluminescence and fluorescence detectors. The results showed that PAH concentrations were higher
Taiwan
Many atmospheric PAH works have been conducted in Taiwan over the last decade. PAH samples from the ambient air in traffic, industrial and work-place environments were studied to determine concentrations, particle-bound PAH compositions, phase distributions, and temporal and spatial variations. Lee et al. (1995) used a total suspended particle sampler (General Metal Works, PS-1) with glass fiber filters and glass cartridges that contained polyurethane foam (PUF) and XAD-2 resins to collect
Summary
Table 1, Table 2 summarize this review paper. Table 1 shows the collection of PAH samples in Asia and the experimental methods. Table 2 summarizes the PAH results in Asia. The experimental methods for sampling PAH have five steps: (1) collection, (2) extraction, (3) drying, (4) cleaning and (5) analysis. PAHs in particulate and gaseous phases from ambient air were collected. A high-volume sampler, a PM10/PM2.5 specific sampler and an impactor are usually applied to collect particles. Filters
Acknowledgment
The authors would like to thank the National Science Council of the Republic of China for financially supporting this research.
References (36)
- et al.
Temporal and spatial variations of the particle size distribution of PAH and their dry deposition fluxes in Korea
Atmospheric Environment
(2002) - et al.
Polycyclic aromatic hydrocarbons in the urban atmospheric particulate matter in the city of Naples (Italy)
Atmospheric Environment
(1999) - et al.
Characteristic study of polycyclic aromatic hydrocarbons for fine and coarse particulates at Pastureland near Industrial Park sampling site of central Taiwan
Chemosphere
(2005) - et al.
Particle-associated polycyclic aromatic hydrocarbons in urban air of Hong Kong
Atmospheric Environment
(2003) - et al.
Atmospheric bulk deposition of PAHs onto France: trends from urban to remote sites
Atmospheric Environment
(2002) - et al.
Comparison of polycyclic aromatic hydrocarbons and nitropolycyclic aromatic hydrocarbons in airborne particulates collected in downtown and suburban Kanazawa, Japan
Atmospheric Environment
(2002) - et al.
Characterization of selected volatile organic compounds, polycyclic aromatic hydrocarbons and carbony1 compounds at a roadside monitoring station
Atmospheric Environment
(2002) - et al.
Atmospheric polycyclic aromatic hydrocarbons in Mumbai, India
Atmospheric Environment
(2000) - et al.
Development of an improved dry and wet deposition collector and the atmospheric deposition of PAH onto Ulsan Bay, Korea
Atmospheric Environment
(2004) - et al.
PAH characteristics in the ambient air of traffic-source
The Science of the Total Environment
(1995)
Polycyclic aromatic hydrocarbons (PAHs) and carbonyl compounds in urban atmosphere of Hong Kong
Atmospheric Environment
Indoor characteristics of polycyclic aromatic hydrocarbons in the urban atmosphere of Taipei
Atmospheric Environment
Chemical characterization and source identification/ apportionment of fine and coarse air particles in Thessaloniki, Greece
Atmospheric Environment
Critical review on atmospheric PAH. Assessment of reported data in the Mediterranean basin
Fuel Process Technology
Mobile sources of atmospheric polycyclic aromatic hydrocarbons in a roadway tunnel
Atmospheric Environment
Polycyclic aromatic hydrocarbons (PAHs) in Chicago air
The Science of the Total Environment
Source identification of Malaysian atmospheric polycyclic aromatic hydrocarbons nearby forest fires using molecular isotopic compositions
Atmospheric Environment
Concentrations of PAHs in atmospheric particles (PM-10) and roadside soil particles collected in Kuala Lumpur, Malaysia
Atmospheric Environment
Cited by (267)
PM<inf>2.5</inf>-bound polycyclic aromatic hydrocarbons of a megacity in eastern China: Source apportionment and cancer risk assessment
2023, Science of the Total EnvironmentEffect of Polycyclic Aromatic Hydrocarbons (PAHs) on Respiratory Diseases and the Risk Factors Related to Cancer
2023, Polycyclic Aromatic CompoundsModeling polycyclic aromatic hydrocarbons in India: Seasonal variations, sources and associated health risks
2022, Environmental ResearchEffects of benzo[a]pyrene exposure on oxidative stress and apoptosis of gill cells of Chlamys farreri in vitro
2022, Environmental Toxicology and Pharmacology