Seasonal variation and health risk assessment of atmosphericPM2.5-bound polycyclic aromatic hydrocarbons in a classicagglomeration industrial city, central China

Sixty atmospheric sample concentrations of PM2.5 and polycyclic aromatic hydrocarbons (PAHs) in PM2.5 were analyzed in distinct seasonal variations from a classic agglomeration industrial city. The concentrations of PM2.5 ranged from 6.96 to 260.06 μg/m3 with an average of 177.05 μg/m3. Only 38% of the sampling days were superior to the 24-h limit value (75 μg/m3) of ambient air quality standards (AAQs), and the samples from autumn and winter exceeded the limit value. The total PAHs ranged from 1.51 to 44.51 ng/m3 with an average of 10.65 ng/m3. The highest and lowest concentrations of total PAHs appeared in winter and summer with averages of 22.56 and 4.03 ng/m3, respectively. Correlation analysis revealed that high-molecular-weight PAHs (HMW-PAHs) (4-, 5-, 6-ring PAHs) were significantly and negatively correlated with temperature and water-soluble total organic carbon (WTOC), and significantly correlated with water-soluble total nitrogen (WTN). The 4-, 5- and 6-ring PAHs were dominant, especially those of 4-ring PAHs, which were above 30% of the total PAHs in each season. Source apportionment indicated that PM2.5-bound PAHs in Huangshi were mainly derived from pyrogenic source, vehicle exhaust, coal combustion, and biomass burning. Incremental lifetime cancer risks (ILCRs) showed no potential carcinogenic risk from the PM2.5-bound BaP-eq. ILCRs in winter were the highest, and the risks for adults were approximately an order of magnitude higher than those for children

Sources and Formation Processes of Short-Chain Saturated Diacids (C2–C4) in Inhalable Particles (PM10) from Huangshi City, Central China

PM10 samples were collected from Huangshi (HS) city, Central China during April 2012 to March 2013, and were analyzed for short-chain saturated dicarboxylic acids (diacids) using a capillary gas chromatograph (GC). We found that oxalic acid (C2, 318 ± 104 ng·m−3) was the most abundant diacid species, followed by malonic acid (C3, 25.4 ± 9.11 ng·m−3) and succinic acid (C4, 2.09 ± 0.52 ng·m−3). The concentrations of C2 and C4 diacids were highest in winter, followed by summer and spring, and lowest in autumn. C3 diacid was decreased in the order of summer > winter > autumn > spring. Further, the seasonal variations of WSOC (water-soluble organic carbon)- and OC (organic carbon)-normalized diacid concentrations were similar to those of diacid concentrations, suggesting that both primary emission and secondary production are important sources for diacids in Huangshi (HS) aerosols. Strong correlations were found among C2 diacid and the three ions SO42−, NO3−, and NH4+ in summer and winter, suggesting that the species could undergo a similar secondary oxidation processing. C2 had good correlation with K+ in summer and autumn, which indicates an enhanced contribution of combustion sources for C2 diacid. Moreover, according to the ratio of C2/K+, we can conclude that C2 diacid should be formed by a secondary reaction of biomass combustion in HS aerosols, especially in summer and autumn. The ratios of C2/C4 and C3/C4 were compared with those reported in other sites, and the results suggest that HS aerosols should be more photochemically aged than at other urban areas. Principal component analysis of diacids and selected water-soluble inorganic ions over four seasons suggests that HS aerosols are influenced not only from primary emission, but also from secondary reaction. According to the linear relation between C2 and C3 diacids, the results indicate that C2 diacid is formed from the oxidation of hydrocarbon compounds in spring, while it is from the oxidation of C3 and C4 diacids in summer, autumn, and winter

Characterization of Polycyclic Aromatic Hydrocarbons (PAHs), Iron and BlackCarbon within Street Dust from a Steel Industrial City, Central China

Twenty-two street dust samples collected from a small steel city, central China, were analyzed for 16 USEPA priority PAHs to investigate the concentration, spatial distribution relationship with black carbon (BC) and Iron (Fe), and the source apportionment and to assess the health risk of these compounds. The mean contents of PAHs, BC and Fe were 4.43 &micro;g g&ndash;1, 12837.97 mg kg&ndash;1, 70205.70 mg kg&ndash;1, respectively. The highest spot was in the surrounding of the E&rsquo;zhou Steel Plant and the Steel Rolling Mill of E&rsquo;zhou. The correlation analysis indicated that there was no obvious relationship between Fe with each other, the PAHs significantly correlated to black carbon (BC), which might be caused by the continuous emission sources of iron and steel production. The results of sources identification suggested that PAHs contaminations in street dust were a mixed source of industrial production and traffic emission combustion. The incremental lifetime and cancer risks (ILCRs) of exposing to PAHs in the street dust of the E&rsquo;zhou city for the three age groups (namely childhood, adolescence, adulthood) fluctuated with in the range of 10&ndash;6 to 10&ndash;4, indicating a potential of carcinogenic risk for exposed populations.</p

Characteristics and Sources of Black Carbon in Atmospheric Dustfall Particlesfrom Huangshi, China

Concentrations of carbonaceous particles in atmospheric dustfall particles in Huangshi, an industrial city in central China, were determined using a thermal-optical reflectance method. The black carbon (BC) contents in ninety-five dustfall samples ranged from 4.3 to 64.9 g kg⁻&sup1; with an average of 17.0 g kg⁻&sup1;. These values were higher than those in world background soils and demonstrated serious contamination of the environment in this city. Overall, BC accounted for 17.6-71.3% (mean: 42.0%) of the organic carbon (OC), and BC and OC were positively correlated (r&sup2; = 0.90). Average char and soot contents were 8.01 g kg-1 and 8.65 g kg⁻&sup1;, respectively, and char/soot ratios ranged from 0.28 to 1.97 with an average of 1.01. All the measured carbonaceous species positively correlated with each another, suggesting their common sources. BC, char, and soot showed large spatial distribution variability, with high levels of BC adjacent to the presumed emission sources, such as a power plant and railway line. Analyses of BC/OC and char/soot ratios indicate major impacts from fossil fuel combustion, especially motor vehicle emissions and coal combustion. Industrial dusts related to coal use appear to be the major contributor to BC in dustfall, and this is likely related to the extensive industrial activities in the city, including metal smelting.</p