Atmospheric Concentrations Of Polycyclic Aromatic Hydrocarbons Research Articles

1-Hydroxypyrene and 3-hydroxybenzo[ a]pyrene as biomarkers of exposure to PAH in various environmental exposure situations

Objective To evaluate the utility of urinary 3-hydroxybenzo[ a]pyrene (3-OH-B[ a]P) as a biomarker of exposure to polycyclic aromatic hydrocarbons (PAHs) in various environmental exposure scenarios alongside the more usually studied 1-hydroxypyrene (1-OH-Pyr). Methods Two groups of 15 and 10 non smoking, healthy men and women, were exposed for approximately 6 h to ambient air at two outdoor locations close to metallurgical industries, and at one indoor location in an urban setting. Atmospheric measurements of 16 “priority” PAHs were carried out during each exposure. Urinary 1-OH-Pyr and 3-OH-B[ a]P were also analysed, samples being taken the morning before exposure, at the end of exposure, then 4 and 15 h after the end of exposure. Urinary 1-OH-Pyr and 3-OH-B[ a]P were analysed using high performance liquid chromatograph with fluorescence detection. Limits of detection (LOD) were 0.092 nmol/L and 0.28 pmol/L for 1-OH-Pyr and 3-OH-B[ a]P respectively. Results Average ambient air concentrations varied from 0.27 to 2.87 ng/m 3 for pyrene, 0.04 to 1.20 ng/m 3 for B[ a]P, and from 70.0 to 910.6 ng/m 3 for the sum of the 16 PAH (ΣPAHs). Concentrations of 1-OH-Pyr were not correlated with atmospheric concentrations of PAHs to which subjects were exposed, nor with the concentrations of 3-OH-B[ a]P. Nearly 80% of measurements of 3-OH-B[ a]P were lower than the LOD and no relationship between atmospheric concentrations and urinary metabolites was observable. However, the percentage of post-exposure values of 3-OH-B[ a]P greater than the LOD increased significantly with the median of atmospheric concentrations of Pyr, B[ a]P and ΣPAH at the different sites (test of linear trend, p < 0.02 in all cases). Conclusion Although we used very sensitive techniques for the measurements of urinary metabolites, especially for 3-OH-B[ a]P, neither 1-OH-Pyr nor 3-OH-B[ a]P were an unequivocal biomarker of exposure to atmospheric PAHs in environmental exposure scenarios relevant to the general population. It would be interesting to investigate other urinary monohydroxy PAH metabolites in this context.

Temporal variation of atmospheric polycyclic aromatic hydrocarbon concentrations in PM10 from the Kathmandu Valley and their gas-particle concentrations in winter

The concentrations of polycyclic aromatic hydrocarbons (PAHs) in particulate matter (PM) with a diameter <10 µm (PM10, 50% cut off) were investigated in the Kathmandu Valley, Nepal, during 2003. In order to understand the dynamics of atmospheric PAHs in winter, the PAH concentrations in total PM and in the gaseous phase were investigated in the valley in December 2005. Total of 45 PAH compounds (∑45PAHs) were analysed by high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS). In 2003, the ∑45PAH concentrations in PM10 ranged between 4.3 and 89 ng m−3 (annual average; 27 ± 24 ng m−3). The average concentrations of ∑45PAHs in December 2005 were 210 ± 33 ng m−3 in total PM and 430 ± 90 ng m−3 in the gaseous phase. The ∑45PAH concentration in PM accounted for more than 30% of the sum of their particulate and gaseous forms. Phenanthrene (Ph) was the most predominant compound in the gaseous phase, whereas four- to seven-ring PAHs were predominant in total PM. The highest values of ∑45PAHs occurred in the winter and spring. Estimates of emission sources based on diagnostic molecular ratios showed that atmospheric PAHs in the Kathmandu Valley mainly originated from the exhaust gas of diesel engine. In the winter and spring, PAH pollution would be accelerated by the operations of brick kilns and the frequent formation of an atmospherically stable layer in the valley.

Atmospheric particulate polycyclic aromatic hydrocarbons from road transport in southeast Brazil

The Cubatão industrial complex of southeast Brazil is sited on a coastal strip bounded on the continental side by a mountainous scarp covered with tropical forest. Four cities have developed around the complex. The metropolitan region of São Paulo is located on a plateau above the scarp. The combination of the region’s topography, the industrial installations, and an intensely trafficked road network causes widespread atmospheric pollution. In November 2004, measurements were made of the 16 polycyclic aromatic hydrocarbons designated as priority pollutants by the US Environmental Protection Agency, as well as of aerosol mass and ionic composition. Use of characteristic concentration ratios for emission sources show that tailpipe emissions from diesel vehicles was the main source of the compounds. This means that a shift from gasoline to ethanol as fuel in spark ignition engines will have only minor influence on atmospheric polycyclic aromatic hydrocarbon concentrations, despite very low emissions during ethanol combustion. On the other hand, reduction in emissions associated with increasing use of biodiesel in compression ignition engine fuel mixtures could significantly reduce atmospheric concentrations.

Seasonal trends in vegetation and atmospheric concentrations of PAHs and PBDEs near a sanitary landfill

Spruce needle and atmospheric (gaseous and particulate-bound) concentrations were surveyed near a sanitary landfill from February 2004 to June 2005. The influence of several parameters such as temperature, relative humidity, wind speed and direction, as well as increased domestic heating during the winter was assessed. In general, polybrominated diphenyl ethers (PBDE) and polycyclic aromatic hydrocarbons (PAH) concentrations in spruce needles increased over time and decreased following snowmelt with a minimum coinciding with bud burst of deciduous trees. Atmospheric concentrations of PBDE and PAH, both particulate-bound and gaseous phase, were linked to daily weather events and thus showed more variability than those in spruce needles. Highest PAH concentrations were encountered during the winter, likely reflecting increased emission from heating homes. Pseudo Clausius-Clapeyron plots revealed higher PBDE gaseous concentrations with increasing temperature, but showed no correlation between PAH gaseous concentrations and temperature as this effect was obscured by seasonal emission patterns. Finally, air mass back trajectories and local wind directions revealed that particulate-bound PBDEs, along with both gaseous and particulate-bound PAHs were from local sources, whereas gaseous PBDEs were likely from distant sources.

Atmospheric Polycyclic Aromatic Hydrocarbons in North China: A Winter-Time Study

The contamination and outflow of atmospheric polycyclic aromatic hydrocarbons (PAHs) in the Chinese Northern Plain, a region with a total area of 300 000 km2 and a high PAH emission density, were investigated. Polyurethane foam (PUF) and PM10 samples were collected at 46 sites located in urban, rural (towns or villages), and control (remote mountain) areas in the winter from November 2005 to February 2006. The observed concentrations of atmospheric PAHs were generally higher than those reported for developed countries and southern Chinese cities. It was found that there was no significant difference in air PAH concentrations between the urban and the rural areas (514 +/- 563 ng/m3 and 610 +/- 645 ng/ m3, respectively), while the PAH concentrations at the control sites (57.1 +/- 12.6 ng/m3) were 1 order of magnitude lower than those at the other sites. The primary reason for the similarity in PAH concentrations between urban and rural areas was the fact that the predominant sources of biomass and domestic coal combustion were widely spread over the study area. The partition constants (K(PM10)) of PAHs were significantly correlated to the corresponding values of subcooled liquid-vapor pressure (pL0). However, the regression slopes of log K(PM10) versus log pL0 were much steeper than -1, indicating adsorption dominated over absorption. Three distinct patterns of outflow from the study area were identified by forward trajectory and cluster analysis.

Polycyclic aromatic hydrocarbons study and toxic equivalency factor (TEFs) in Tehran, IRAN

Polycyclic aromatic hydrocarbons (PAHs) are toxic pollutants released by various urban combustion sources. Benzo[a]pyrene (BaP) is a representative member of the class of PAHs. Health risk assessment associated with inhalatory PAHs uptake is often estimated on the basis of the BaP concentrations in air. Atmospheric particulate PAHs concentrations were measured at five locations in Tehran, Iran. Sixteen PAHs were extracted from the airborne particles and analyzed by HPLC. Total PAHs concentrations (16 compounds) at five station Arjanteen, Enghelab, Azadi, Bahman, Haft Houz were respectively, 70.2, 96.5, 130, 79.1, 44.1 ng/m(3). The information obtain from the present study indicated that mean of human carcinogens are: benzo[a]antheracene (0.17-4.76 ng/m(3)), chrysene (1.74-3.62 ng/m(3)), benzo[b]fluoranthene (0-5.25 ng/m(3)), benzo[k]fluoranthene (0.32-1.72 ng/m(3)), benzo[a]pyrene (1.41-3.82 ng/m(3)), dibenzo[a,h]anthracene (0.33-2.13 ng/m(3)), and indeno[1,2,3-cd]pyrene (0.25-11.08 ng/m(3)). The development and the establishment of a toxicity equivalency factor (TEF) are used in the assessment of mixtures containing PAHs. The contribution of the carcinogenic potency of BaP alone is in the range of 49.6-76.3% of the total carcinogenic activity. The annual number of lung cancer cases (persons per million) among Tehran residents (population = 10 millions) attributable to these carcinogenic PAHs compounds in 2005 was estimated at 58 persons per million. In Tehran urban areas vehicular emission are the primary contributor to PAHs concentrations, with additional local contributors like industrials emissions.

Characteristics of wintertime polycyclic aromatic hydrocarbon assemblage in aerosol of the Southern Adriatic

Features of polycyclic aromatic hydrocarbon (PAH) assemblage in aerosol samples collected from the atmosphere of Herceg Novi during the winter months of two successive years were studied. The results showed almost the same concentration profiles of identified PAHs for samples from the two periods analyzed, generally suggesting a similar origin. Diagnostic ratios indicated combustion of wood and coal, emissions from petrol and diesel engines, and dust resuspension as sources that predominantly contributed to the atmospheric PAH concentrations. Statistical analysis, principal component analysis (PCA) in particular, allowed us to identify the impact of meteorological parameters on PAH abundance.

Estimation of the emission factors of PAHs by traffic with the model of atmospheric dispersion and deposition from heavy traffic road

In order to consider the total atmospheric loadings of the PAHs (polycyclic aromatic hydrocarbons) from traffic activities, the emission factors of PAHs were estimated and from the obtained emission factors and vehicle transportation statistics, total atmospheric loadings were integrated and the loadings into the water body were estimated on a regional scale. The atmospheric concentration of PAHs was measured at the roadside of a road with heavy traffic in the Hiroshima area in Japan. The samplings were conducted in summer and winter. Atmospheric particulate matters (fine particle, 0.6-7 microm; coarse particle, over 7 microm) and their PAH concentration were measured. Also, four major emission sources (gasoline and diesel vehicle emissions, tire and asphalt debris) were assumed for vehicle transportation activities, the chemical mass balance method was applied and the source partitioning at the roadside was estimated. Furthermore, the dispersion of atmospheric particles from the vehicles was modelled and the emission factors of the sources were determined by the comparison to the chemical mass balance results. Based on emission factors derived from the modelling, an atmospheric dispersion model of nationwide scale (National Institute of Advanced Industrial Science and Technology - Atmospheric Dispersion Model for Exposure and Risk assessment) was applied, and the atmospheric concentration and loading to the ground were calculated for the Hiroshima Bay watershed area.

Seasonal Influence on Vapor-and Particle-Phase Polycyclic Aromatic Hydrocarbon Concentrations in School Communities Located in Southern California

Ambient concentrations of 15 vapor-and particle-phase (PM 2.5 ) polycyclic aromatic hydrocarbons (PAHs), listed by the US EPA as priority pollutants, were measured between July 2002 and November 2003 in six Southern California communities participating in a multi-year chronic respiratory health study of schoolchildren. The communities were geographically distributed over two hundred kilometers, extending from Long Beach in coastal Los Angeles, to high mountain areas to the north and west of the Los Angeles basin, and south into Eastern San Diego County. Seasonal and spatial variation in the atmospheric concentrations of PAHs is of interest because this class of compounds includes potent mutagens, carcinogens, and species capable of generating reactive oxygen species (ROS) that may lead to oxidative stress. Naphthalene accounted for 95% of the total PAH mass; annual averages ranged from 89 to 142 ng m − 3 . Benzo[ghi]perylene (BGP) and the pro-carcinogen benzo[a]pyrene (BAP), present almost exclusively in ...

Long-range transport of polycyclic aromatic hydrocarbons from China to Japan

Airborne particulate matter was collected at Wajima, on the Noto Peninsula, Ishikawa, Japan by a high-volume air sampler with a quartz filter every week from 17 September 2004 to 16 September 2005. Polycyclic aromatic hydrocarbons (PAHs) extracted from filters were analyzed by HPLC with fluorescence detection. The atmospheric concentrations of PAHs at Wajima were higher during the heating period of China (when coal is burned for heat) than during the no-heating period. A meteorological analysis indicated that the air samples collected in that heating period at Wajima were transported mainly from Northeast China over the Japan Sea. Principal component analysis of nine PAHs indicated a Chinese origin of the PAHs. These results strongly suggest that the high-level PAHs detected at Wajima were the result of long-range transport from China.

Measurement of DNA Adducts as Biomarkers of Genotoxic Exposure to Benzo[A]Pyrene Using a LC-MS/MS Technique

P-133 Introduction: Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants representing the first family of carcinogenic pollutants in professional environment. It is now well established that some of these molecules including the tumorigenic benzo[a]pyrene (BaP) are responsible for the apparition of lung, skin and bladder cancers. It is therefore of major importance to evaluate individual exposure to carcinogenic PAHs in order to improve health risk assessment. In addition to the classical determination of atmospheric concentrations of gaseous and particulate PAHs and 1-hydroxyprene excreted in urine, we are interested in measuring specific urinary metabolites and DNA adducts of BaP. Methods: A high performance liquid chromatography coupled to fluorescence detection (HPLC-Fluo) method has been set-up for the urinary determination of 3-hydroxybenzo[a]pyrene (3-OHBaP) and BaP tetrol, and compared to a HPLC coupled to tandem mass spectrometry (HPLC-MS/MS) method. This technique already used for the quantification of 8-oxo-7,8-dihydro-2′-désoxyguanosine was also developed for the measurement of several DNA adducts of BaP. Results: The limit of detection (LOD) obtained for 3-OHBaP is 0.4 ng/L of urine thanks to a double-step procedure of purification and concentration of urinary samples on Sep-Pak cartridges followed by an on-line extraction on the HPLC-Fluo system, and is not improved using a tandem mass spectrometric detection. The LOD of BaP tetrol is currently determined. HPLC-MS/MS allows a highly sensitive and specific detection and quantification of eight stable and depurinating DNA adducts of BaP. These include five DNA adducts of the carbocation pathway and three adducts arising from the BaP-diol-epoxyde pathway. The corresponding limits of detection range from 1 to 40 injected fmoles. Discussion and Conclusions: In the weeks coming, our developed analytical tools will be applied to measure BAP metabolites, DNA adducts and DNA oxidative damages in urinary samples obtained from volunteers professionally exposed to PAHs. The results should be of main importance to identify pertinent biomarkers in order to measure exposure to BaP and assess health risks of workers which may orientate preventing actions.

Spatial distribution and seasonal variations of polycyclic aromatic hydrocarbons (PAHs) using semi-permeable membrane devices (SPMD) and pine needles in the Pearl River Delta, South China

Semi-permeable membrane devices (SPMDs) were deployed at 12 sites in the Pearl River Delta (PRD) during 2001–2002 to elucidate the spatial distribution and seasonal variations of polycyclic aromatic hydrocarbons (PAHs) in the subtropical region. Pine needles from the same sites were also analyzed for PAHs for a comparison with SPMDs. In Guangzhou, high volume active air sampling (HiVol) was carried out weekly through out the year-round sampling campaign. The PAHs sequestered in SPMDs (in ng SPMD −1 day −1) were found to be higher in winter than in summer. Using the HiVol data, SPMD sampling rates were calculated seasonally for some dominant gas-phase PAH compounds (Fluorene to Pyrene). These sampling rates ranged from 0.7 to 2.8 m 3 day −1, which were used to determine the atmospheric PAH concentrations at other sites. The calculated PAH concentrations, based on different temperature-dependant SPMD sampling rates, in the air were higher in summer than in winter. The PAH compounds sampled with SPMDs and pine needle were mainly associated with gaseous PAHs, while pine needles accumulated more high molecular weight (HW) PAHs. Good agreements were found in the spatial distribution of atmospheric PAHs measured by SPMDs and pine needles. The potential of using SPMDs for seasonal monitoring of atmospheric organic pollutants at a regional scale was demonstrated.

Dry deposition of polycyclic aromatic hydrocarbons in urban and rural sites of Western Greece

The dry deposition of 12 polycyclic aromatic hydrocarbons (PAHs) was measured at an urban (Kozani), an adjacent coastal (Vegoritis) and a continental background site (Petrana) located in the Eordea basin, western Greece. Mean dry deposition fluxes of 3917, 3346 and 5648 ng m −2 month −1 (0.13, 0.11 and 0.19 μg m −2 day −1) were found in Petrana, Vegoritis and Kozani, respectively. Differences among sites were attributed to their different impact from emission sources and to differences in prevailing meteorological conditions. The correlation of dry deposition fluxes with particle- and gas-phase PAH concentrations determined at the three sites during the same sampling periods was investigated. Dry deposition velocities ( V d) were calculated by dividing deposition fluxes with the corresponding average ambient PAH concentrations. The low V d values obtained suggest that gas phase PAHs and fine particle associated PAHs dominate their dry deposition. The influence of air mass movements to dry deposition and atmospheric concentrations of PAHs in the area was also investigated.

Polycyclic aromatic hydrocarbons and nitropolycyclic aromatic hydrocarbons in urban air particulates and their relationship to emission sources in the Pan–Japan Sea countries

Abstract Airborne particulates were collected in seven cities in the Pan–Japan Sea countries, Shenyang (China), Vladivostok (Russia), Seoul (South Korea), Kitakyushu, Kanazawa, Tokyo and Sapporo (Japan), in winter and summer from 1997 to 2002. In addition, particulates from domestic coal-burning heaters and diesel engine automobiles were collected in Shenyang and Kanazawa, respectively. Nine polycyclic aromatic hydrocarbons (PAHs) and four nitropolycyclic aromatic hydrocarbons (NPAHs) in the extracts from the particulates were analysed by HPLC with fluorescence and chemiluminescence detections, respectively. The PAHs were fluoranthene, pyrene (Pyr), benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, benzo[ghi]perylene and indeno[1,2,3-cd]pyrene, and NPAHs were 1,3-, 1,6-, 1,8-dinitropyrenes, and 1-nitropyrene (1-NP). Mean atmospheric concentrations of PAHs in Shenyang and Vladivostok were substantially higher than those in Seoul, Tokyo, Sapporo, Kitakyushu and Kanazawa. However, the mean atmospheric concentrations of NPAHs were at the same levels in all cities except Kitakyushu. The expected seasonal variations (greater PAH and NPAH concentrations in winter than in summer) were observed in all cities. In order to study the major contributors of atmospheric PAHs and NPAHs, both cluster analysis and factor analysis were used and three large clusters were identified. Furthermore, the concentration ratios of 1-NP to Pyr were significantly smaller in Shenyang, Vladivostok and Kitakyushu and the values were close to those observed in particulates from coal stove exhaust. By contrast, in Seoul, Kanazawa, Tokyo and Sapporo the [1-NP]/[Pyr] ratio reached values similar to those of particulates released from diesel-engine automobiles. The [1-NP]/[Pyr] concentration ratio seemed to be a suitable indicator of the contribution made by diesel-engine vehicles and coal combustion to urban air particulates.

Atmospheric Reactions Influence Seasonal PAH and Nitro-PAH Concentrations in the Los Angeles Basin

Ambient measurements of polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs were carried out during August 2002 and January 2003 in Los Angeles, CA, a source site and in Riverside, CA, a downwind receptor site approximately 90 km to the east of Los Angeles. Atmospheric concentrations of PAHs and nitro-PAHs are of interest because both of these compound classes include potent mutagens and carcinogens. To augment our current understanding of atmospheric formation of nitro-PAHs, four sampling periods were employed to study the diurnal variations of these compounds. The PAH concentrations were highest in Los Angeles during January, as a result of traffic input at this source site undertightwintertime atmospheric inversions. In contrast, nitro-PAH levels were highest in Riverside during August, as a result of enhanced summertime photochemistry. Hydroxyl radical-initiated reactions produced nitro-PAHs in both seasons, while in winter little evidence for nitrate radical chemistry was seen. For the August samples, nitrate radical-initiated formation of nitro-PAHs is suggested by nitro-PAH isomer profiles not only at the downwind location as anticipated, but also atthe source site. In southern California, the contribution of atmospheric formation through gas-phase radical-initiated PAH reactions to the ambient burden of nitro-PAHs is dominant, with the semi-volatile nitro-PAHs being the most abundant and 2-nitrofluoranthene being the major particle-associated nitro-PAH.

Gas/particle partitioning of seven volatile polycyclic aromatic hydrocarbons in a heavy traffic urban area

Air samples (vapor- and particle-phase) were taken for 19 sampling events during the period from December 1997 to July 1998 in an urban site in the center of Athens. The urban site is densely populated and characterized by heavy traffic circulation and elevated concentrations of VOCs, NO x , CO and smoke. Seven volatile polycyclic aromatic hydrocarbons (PAHs) were determined in samples. The temperature dependence of gas-phase atmospheric concentration of PAHs, C g, was investigated using diagrams of natural logarithm of partial pressures (ln P) vs. reciprocal mid-point temperatures. For the six of seven volatile PAHs, the temperature dependence of ln P was statistically significant (at least at the 90% confidence level) and the temperature accounted for 21–67% of the variability in gas-phase concentrations. The gas-phase concentration C g of the very volatile PAHs was affected more significantly by changes in temperature, but the variation of the less-volatile PAHs fluoranthene and pyrene C g, was better explained by changes in temperature. The temperature dependence of gas/particle partitioning constant K P was also examined. Regressions of log( K P) −1 vs. T −1 for fluorene, fluoranthene and pyrene were classified into two different temperature ranges. The gas/particle partitioning of PAHs was studied by correlating the partition constant to the sub-cooled liquid saturation vapor pressure ( P L o). The Junge adsorption model underestimated the particle fraction of volatile PAHs probably due to the presence of non-exchangeable fraction. Slopes ( m r) of the regressions log K P vs. log P L o were different from the value −1 as Pankow's theory predicts. The short distance between the sampling point and the emission sources is also estimated to be a factor that causes deviations from the theoretical value. Evidence that atmospheric conditions favorable for secondary aerosol formation coincide with higher value of m r, was provided by limited sampling events. An interrelation was found to exist between the m r values, allowing the prediction of the gas/particle partitioning of a series of seven PAHs by the measurement of a single PAH partitioning.

Distribution of polycyclic aromatic hydrocarbons in the atmosphere of Hong Kong.

This paper reports the monitoring results of eleven polycyclic aromatic hydrocarbons (PAHs), four to six-ring, at two urban sites-Central & Western (CW) and Tsuen Wan (TW) in Hong Kong from January to December 2000; and the findings of a study conducted in 2001 of the partitioning of the gaseous and particulate phases of PAHs. The sum of the eleven PAHs under study (sigmaPAHs) was found to range from 6.46 to 38.8 ng m(-3). The annual mean levels at 12.2 ng m(-3) and 15.8 ng m(-3) for CW and TW respectively are comparable to those recorded for the previous two years and are also within the reported ranges for other metropolitan cities in the Asia Pacific region. Amongst the selected eleven PAHs, fluoranthene and pyrene were the two most abundant found in the urban atmosphere of Hong Kong during the study period accounting for approximately 80%, of the total PAHs. The ratios of benzo(a)pyrene to benzo(g,h,i)perylene (BaP/BghiP) and indeno(1,2,3-cd)pyrene to benzo(g,h,i)perylene (IDP/BghiP) indicate that diesel and gasoline vehicular exhausts were the predominant local emission sources of PAHs. Seasonal variations with high winter to summer ratios for each of the individual PAHs (CW: 1.6-16.7 and TW: 0.82-8.2) and for sigmaPAHs (CW: 1.9 and TW: 1.8) and a spatial variation of BaP amongst the air monitoring stations are noted. Results of correlation studies illustrate that local meteorological conditions such as ambient temperature, solar radiation, wind speed and wind direction have significant impact on the concentrations of atmospheric PAHs accounting for the observed seasonal variations. A snapshot comparison of the concentrations of PAHs at four sites including a roadside site, a rural site and the two regular urban sites CW and TW was also performed using the profiles of PAHs recorded on two particulate episode days in March 2000.

Spatial and temporal PAH concentrations in Zaragoza, Spain

The concentration of seven polycyclic aromatic hydrocarbons (PAH) associated with the atmospheric solid phase was measured in the Zaragoza (North-East of Spain) atmosphere using fluorescence spectroscopy in the synchronous mode (FS). The PAH results were reported for four different urban and suburban places, located within the city and during the period October 1999–September 2001. The PAH data obtained indicated the importance of local sources generated from urban/industrial areas. Although the PAH total concentration was quite similar in all the sampling sites, the main differences were due to Benzo[ a]pyrene (B aP) and Coronene (Cor) concentrations, reaching the highest values in the sites associated with heavy traffic (trucks, lorries, etc.). The temporal evolution of atmospheric solid phase PAH concentrations indicated a seasonal trend. Higher PAH concentrations were found during colder seasons for the four sampling sites. The influence of environmental parameters such as temperature, rain, relative humidity, wind speed and direction on the PAH emissions was analyzed observing a positive correlation between the total PAH concentration and the relative humidity and a negative one with the temperature. With regard to the wind direction, higher PAH emissions were detected when wind was coming from an east and north-east direction. Wind from a north-westerly direction showed lower PAH emissions associated with the cierzo wind which provided cleaner air.

Polycyclic aromatic hydrocarbons in a semiaquatic plant and semipermeable membrane devices exposed to air in Thailand.

Semipermeable membrane devices (SPMDs) were deployed at six sites in the Bangkok region, Thailand, to investigate spatial variations in atmospheric concentrations of polycyclic aromatic hydrocarbons (PAHs). Sampling sites affected by various levels of traffic intensity were studied. In addition, PAH levels were determined in a common human food plant (water spinach) harvested from canals and ponds in the sampling areas. Significant differences in atmospheric PAH concentrations between sites were found, with 10 times higher PAH levels in the urban areas compared to the rural areas. Increasing concentrations of 1-methylphenanthrene relative to phenanthrene were found in the urban air close to the city center, indicating that traffic probably contributed to the higher PAH concentrations detected. Due to SPMD's passive sampling technique, their long-term operation and high ability to detect spatial differences, they proved to be suitable for semiquantitative field studies of PAHs. The PAH compounds sampled with SPMDs were mainly associated with gaseous PAHs, while both gas phase and particle-bound PAHs were detected in the plant samples. The relative abundance ratios of some PAHs in the plants were not well correlated with the ratios detected in the SPMDs, indicating that gas-phase exposure made low contribution to the PAH concentrations in the plants. However, similarities in the profiles of 3-ring PAHs between the SPMD and plant samples indicate that gas-phase exchange occurs between the atmosphere and the plants.

Picogram quantitation of polycyclic aromatic hydrocarbons adsorbed on aerosol particles by two-step laser mass spectrometry.

Polycyclic aromatic hydrocarbons (PAHs) are emitted into the atmosphere mostly by anthropogenic combustion sources. Because of their carcinogenic and mutagenic properties, PAHs are often analyzed in air quality measurements. Atmospheric concentrations of PAHs, typically in the nanograms-per-cubic-meter range, require significant effort for sample collection and processing when conventional methods such as gas chromatography/mass spectrometry (GC/MS) or liquid chromatography/mass spectrometry are used. In contrast, two-step laser mass spectrometry (L2MS) is highly sensitive and selective for PAHs and requires almost no sample preparation. Here, we present for the first time a method based on L2MS to quantify PAHs adsorbed on aerosol particles collected on a filter. Linear ranges for quantitation were determined for five different PAHs in the mass range of 178-276 Da (i.e., phenanthrene, pyrene, chrysene, benzo[e]pyrene, benzo[ghi]perylene) covering more than 2 orders of magnitude with detection limits between 50 and 300 pg of a single PAH on a whole filter sample. A quantitative comparison with GC/MS was performed using model aerosols consisting of benzo[e]pyrene adsorbed on inorganic salt aerosol particles. On average, 25% less benzo[e]pyrene was determined with GC/MS than with L2MS, with a variability between the two methods of +/-68%. The general lower amount measured with GC/MS is attributed to losses during the sample preparation for the GC/MS measurements.