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The concentration of polycyclic aromatic hydrocarbons (PAHs) in the atmosphere has been continually monitored since their toxicity became known, whereas nitro-PAHs (NPAHs) and oxy-PAHs (OPAHs), which are derivatives of PAHs by primary emissions or secondary formations in the atmosphere, have gained attention more recently. In this study, a method for the quantification of 18 NPAH and OPAH congeners in the atmosphere based on combined applications of gas chromatography coupled with chemical ionization mass spectrometry is presented. A high sensitivity and selectivity for the quantification of individual NPAH and OPAH congeners without sample preparations from the extract of aerosol samples were achieved using negative chemical ionization (NCI/MS) or positive chemical ionization tandem mass spectrometry (PCI-MS/MS). This analytical method was validated and applied to the aerosol samples collected from three regions in Northeast Asia—namely, Noto, Seoul, and Ulaanbaatar—from 15 December 2020 to 17 January 2021. The ranges of the method detection limits (MDLs) of the NPAHs and OPAHs for the analytical method were from 0.272 to 3.494 pg/m3 and 0.977 to 13.345 pg/m3, respectively. Among the three regions, Ulaanbaatar had the highest total mean concentration of NPAHs and OPAHs at 313.803 ± 176.349 ng/m3. The contribution of individual NPAHs and OPAHs in the total concentration differed according to the regional emission characteristics. As a result of the aerosol samples when the developed method was applied, the concentrations of NPAHs and OPAHs were quantified in the ranges of 0.016~3.659 ng/m3 and 0.002~201.704 ng/m3, respectively. It was concluded that the method could be utilized for the quantification of NPAHs and OPAHs over a wide concentration range. [ABSTRACT FROM AUTHOR]

Oxygenated polycyclic aromatic hydrocarbons (OPAHs) are of increasing interest due to their high toxicity. Thirteen particulate PAHs and ten particulate OPAHs were analyzed by Gas Chromatography/Mass Spectrometry (GC/MS) in atmospheric particulate matter with aerodynamic diameters less than or equal to a nominal 2.5 μm (PM 2.5) for the period between May 2020 and January 2021 in Seoul, Republic of Korea. The mean concentration ten OPAHs (5.49 ± 2.40 ng/m3) was higher than that of thirteen PAHs (3.96 ± 3.36 ng/m3), respectively. The concentration of total OPAHs was high in winter (9.40 ± 2.50 ng/m3) and low in summer (3.58 ± 0.78 ng/m3), showing the same trend with PAHs (9.16 ± 3.30 ng/m3 in winter and 0.62 ± 0.15 ng/m3 in summer). When comparing this study results with the measurement results on 2006 in Seoul, PAHs concentration dropped by 68% while only 22% was reduced for OPAHs. It suggests either improvement of combustion technology, i.e., high temperature combustion process in the region or higher ambient oxidation reaction rates on 2020 than 2006. Major sources and their contributions of PAHs and OPAHs were identified based on correlation analysis and Positive Matrix Factorization (PMF) modeling. Two cases were carried. Case 1 is for source apportionment for PM 2.5 and case 2 is for OPAHs and PAHs. The number of factors or sources in the two cases was determined as 7 and 4, respectively. The results of the PMF modeling using diagnostic ratios (DRs) in case 1 identified 7 factors; secondary nitrate (23%), secondary sulfate (21%), vehicles (20%), biomass burning (16%), coal combustion (12%), waste incineration (5%), and OPAHs (5,12-NAQ) emission-related (3%). The PMF modeling results in case 2 revealed 4 factors; vehicles (36%), coal combustion (30%), biomass burning (25%), and OPAHs (5,12-NAQ) emission related (9%). Significant correlation between OPAHs and indicators of primary emission sources, and high contribution from sources with emission characteristics implied that most sources of OPAHs were heavily influenced by primary emissions rather than secondary formation. • 13 particulate PAHs and 10 OPAHs were analyzed in Seoul, Korea for four seasons. • The mean concentration of 10 OPAHs was higher than that of 13 PAHs. • OPAHs were heavily influenced by primary emissions rather than secondary formation. • OPAHs reduction ratios were lower than PAHs from 2006 to 2020. [ABSTRACT FROM AUTHOR]

Abstract: To identify the ambient characteristics of a mega city in Northeast Asia, the particulate PAHs in TSP were measured for 18months at Seoul, the capital of Korea. The average concentration of the ambient particulate PAHs at Seoul for the sampling period was 26.6±28.4ngm−3 with the range from 1.57 to 166ngm−3. It showed winter maxima and summer minimum mainly due to the increased fuel consumption in winter both at Seoul and Northeast Asia. The ambient level of PAHs in Seoul was lower than the cities in China but higher than other urban areas. The stronger relationship between the ambient particulate PAHs concentrations and the inverse of the ambient temperature (1/T) at Seoul compared to Gosan, a background site in Korea and the difference of the distributions of BeP/BaP ratios at Seoul and Gosan might be due to the characteristics of Seoul which was governed by both transport from outside and local emissions. The relationship between the particulate PAHs concentration and (1/T) can be used as an indicator for those two factors for Seoul. [ABSTRACT FROM AUTHOR]

Abstract: The concentrations of particulate Polycyclic aromatic hydrocarbons (PAHs) were measured at Gosan, a background site in Korea for 1year between November 2001 and November 2002. The total concentrations of 14 PAH compounds at Gosan were between 0.52 and 14.76 ng m−3 and about 3–15 times higher than those at other rural or remote sites in the world. Seasonal trend was observed for particulate PAHs concentrations at Gosan with higher levels during heating season due to increased fossil fuel usage and the movement of air parcels from Asian continent. Principal component factor analysis (PCF) for PAHs showed three factors; combination of coal combustion and vehicular emission, natural gas combustion, and unidentified one. However, PCF for the combined data of PAHs, inorganic ions, and elements revealed that the unidentified factor consists of crustal species, sea salts, and four PAH compounds. Thus, this factor is thought to be transport of crustal species with organics from combustion sources. The major variables which determine the sources of PAHs are the heating season and the movement of air parcels from Asian continent. [Copyright &y& Elsevier]

The atmospheric size distributions of particulate polycyclic aromatic hydrocarbons (PAHs) and their deposition fluxes were measured at four sites in August and at three sites in November 1999, in Korea. The total ambient particulate PAHs concentrations at each site ranged between 6.7 and 128.7 ng m−3. In November, the total PAHs concentrations at Inchon (IC) were the highest, followed by Yangsuri (YS) and Seoul (SE). This trend is contrary to the expectation that the total PAHs concentrations at IC and SE be higher than that at YS because IC and SE are highly industrialized large cities and YS is rural area. The size distributions of individual PAHs in IC and SE show trimodal in Dp ≤ 9 µm while the particulate PAHs in YS were distributed evenly to fine- and coarse-size particles. These results suggest that YS has local sources in addition to transport of PAHs emitted from urban sources. The measured dry deposition fluxes of total PAHs ranged from 6.9 to 12.6 µg m−2 day−1 in August, and from 5.9 to 8.5 µg m−2 day−1 in November. Individual PAH fluxes were dominated by high molecular weight (MW) PAHs at all sampling sites in August. But dry deposition fluxes of low MW PAHs were higher than high MW PAHs at all sampling sites in November. This result indicates that major sources of ambient PAHs have seasonal variety. The Sehmel-Hodgson model was used to estimate dry deposition velocities as a function of particle size for the multistep deposition model calculation. The calculated fluxes agreed fairly well with the measured fluxes, and it was shown that large particles (Dp > 9 µm) are more important than small particles (Dp > 9 µm) in particulate dry deposition of PAHs. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs) are primarily emitted into the atmosphere through anthropogenic activities and can be transported to receptor sites at varying distances. In this study, the atmospheric PAH deposition was investigated using a dry deposition plate (DDP) with Mylar, a dry deposition disk (DDD) with Velcro, a resin bulk deposition sampler (Resin-BDS), and a water bulk deposition sampler (Water-BDS) in Ulsan, South Korea, during May–October 2013. Additionally, ambient PAH concentrations were monitored using high-volume air samplers. The mean deposition fluxes of Σ 13 PAHs were 8.62 ± 1.44, 36.9 ± 6.81, 56.9 ± 9.74, and 63.8 ± 8.04 μg/m2/d for the DDP, DDD, Resin-BDS, and Water-BDS, respectively. The DDD was more effective than the DDP because it could collect high molecular weight (HMW) PAHs from dry deposition, which are more toxic than low molecular weight PAHs. The Water-BDS had the highest fluxes of Σ 13 PAHs; however, the Resin-BDS may be more suitable for collecting HMW PAHs from both dry and wet deposition due to relatively constant values for the deposition velocity of PAHs. Furthermore, the PAH fluxes in the Resin-BDS samples were significantly positively correlated with the gaseous and total (gaseous + particulate) concentrations of ambient PAHs. Hence, the fluxes obtained by the Resin-BDS were further used to apply principal component analysis, multiple linear regression, and backward air trajectory simultaneously to identify the emission sources of the deposited PAHs. The results indicate that the combustion of fossil fuels and biomass was the major source. In particular, the industrial complexes using petroleum and coal on the city's east coast and vehicular exhausts were the main local sources. Meanwhile, long-range sources may be forest fires, harbors, and industrial activities in nearby countries. Our study suggests that BDS, considering both dry and wet deposition, can be selectively used for research on PAH deposition. [Display omitted] • The performance of four deposition samplers for ambient PAHs was evaluated. • Dry samplers using Mylar and Velcro collected mostly coarse particle-bound PAHs. • The water and resin bulk samplers were suitable to study both dry and wet deposition. • The resin bulk sampler collected more toxic PAHs with a constant deposition velocity. • The burning of fossil fuels and biomass was a major source of the deposited PAHs. [ABSTRACT FROM AUTHOR]

Seventy three individual organic compounds in the atmospheric particulate matter with an aerodynamic diameter of less than or equal to a nominal 10 μm (PM 10 ) over Seoul were identified and quantified from April 2010 to April 2011 using gas chromatography/mass spectrometry (GC/MS). These organic compounds were classified into five groups, n-alkanes, polycyclic aromatic hydrocarbons (PAHs), mono-carboxylic acids, di-carboxylic acids (DCAs), and sugars based on their chemical structures and properties. The organic compounds showed higher seasonal average concentrations from fall to winter than from spring to summer due to source strength, except some organic compounds among mono-carboxylic acids, DCAs, sugars such as undecanoic acid, methylmalonic acid, and fructose. Through qualitative data analysis using seasonal concentration variations and relevant diagnostic parameters, it was found that (1) anthropogenic sources such as combustion of fossil fuel and biomass burning attributed more to the formation of the organic aerosols than biogenic sources, and (2) the ambient level of n-alkanes, PAHs, and some compounds of DCAs and sugars was elevated in winter due to the increased primary emissions and larger transport from outside of the organic compounds in winter. [ABSTRACT FROM AUTHOR]

Abstract: Polycyclic aromatic hydrocarbons (PAHs) in both gas and total suspended particles were measured at Gosan, Jeju Island in Korea, a remote background site, for 15 days (March 29–April 12, 2002). During the sampling period, a severe three-day Asian dust (AD) event originating from Mongolia and northern China was observed throughout the Korean Peninsula and Jeju Island. In addition, pollution (PO) and normal (NO) periods were also identified based on the levels of anthropogenic pollutants. Despite a large difference of PM10 concentrations between the AD and PO periods, the levels of particulate PAHs in both periods were comparable (2.7±1.0 and 2.4±0.5ngm−3, respectively) since they were determined by the concentration of anthropogenic PM2.5 transported from industrial areas of China. In the AD period, the level of gaseous PAHs, which were mostly from local sources, was the lowest due to strong winds; the gas/particle partitioning was close to equilibrium as the effect of long-range transport was manifested. The results of backward air trajectories, correlation analysis, and diagnostic ratios show that long-range transport of particulate PAHs produced by coal/biomass burning in China could strongly affect the levels and patterns of PAHs at Gosan, Korea. [Copyright &y& Elsevier]

Advanced separation technology paired with mass spectrometry is an ideal method for the analysis of atmospheric samples having complex chemical compositions. Due to the huge variety of both natural and anthropogenic sources of organic compounds, simultaneous quantification and identification of organic compounds in aerosol samples represents a demanding analytical challenge. In this regard, comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GC×GC-TOFMS) has become an effective analytical method. However, verification and validation approaches to quantify these analytes have not been critically evaluated. We compared the performance of gas chromatography with quadrupole mass spectrometry (GC-qMS) and GC×GC-TOFMS for quantitative analysis of eighteen target polycyclic aromatic hydrocarbons (PAHs). The quantitative obtained results such as limits of detection (LODs), limits of quantification (LOQs), and recoveries of target PAHs were approximately equivalent based on both analytical methods. Furthermore, a larger number of analytes were consistently identified from the aerosol samples by GC×GC-TOFMS compared to GC-qMS. Our findings suggest that GC×GC-TOFMS would be widely applicable to the atmospheric and related sciences with simultaneous target and nontarget analysis in a single run. [ABSTRACT FROM AUTHOR]

Understanding the geographic source contributions by particulate polycyclic aromatic hydrocarbons (PAHs) is important for the Korean peninsula due to its downwind location from source areas. Regional influence of particulate PAHs was previously identified using diagnostic ratios applied to mobile source dominated roadside sampling data (Kim et al., 2012b). However, no study has yet been conducted to quantify the regional source contributions. We applied a multivariate receptor modeling tool to identify and quantify the regional source contributions to particulate PAHs in Seoul. Sampling of roadside particulate PAHs was conducted in Seoul, Korea for four years between May 2005 and April 2009, and data analysis was performed with a new multivariate receptor model, Solver for Mixture Problem (SMP). The SMP model identified two sources, local mobile source and transported regional source, and quantified their source contributions. Analysis of the particulate PAHs data reveals three types of episodic periods: a high regional source contribution period with one case, a high mobile source contribution period with three cases, and a normal contribution period with eight cases. Four-year average particulate PAHs source contributions from the two sources are 4.6 ng m −3 and 10.7 ng m −3 for regional and mobile sources, respectively and equivalent to 30% and 70% of the total estimated contribution from each of these sources. [ABSTRACT FROM AUTHOR]