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Hourly-resolved PM 2.5 and PM 10-2.5 samples were collected in the industrial city Foshan in the Pearl River Delta region, China. The samples were subsequently analyzed for elemental components and black carbon (BC). A key purpose of the study was to understand the composition of particulate matter (PM) at high-time resolution in a polluted urban atmosphere to identify key components contributing to extreme PM concentration events and examine the diurnal chemical concentration patterns for air quality management purposes. It was found that BC and S concentrations dominated in the fine mode, while elements with mostly crustal and oceanic origins such as Si, Ca, Al and Cl were found in the coarse size fraction. Most of the elements showed strong diurnal variations. S did not show clear diurnal variations, suggesting regional rather than local origin. Based on empirical orthogonal functions (EOF) method, 3 forcing factors were identified contributing to the extreme events of PM 2.5 and selected elements, i.e., urban direct emissions, wet deposition and a combination of coarse mode sources. Conditional probability functions (CPF) were performed using wind profiles and elemental concentrations. The CPF results showed that BC and elemental Cl, K, Fe, Cu and Zn in the fine mode were mostly from the northwest, indicating that industrial emissions and combustion were the main sources. For elements in the coarse mode, Si, Al, K, Ca, Fe and Ti showed similar patterns, suggesting same sources such as local soil dust/construction activities. Coarse elemental Cl was mostly from the south and southeast, implying the influence of marine aerosol sources. For other trace elements, we found vanadium (V) in fine PM was mainly from the sources located to the southeast of the measuring site. Combined with CPF results of S and V in fine PM, we concluded shipping emissions were likely an important elemental emission source., (Copyright © 2016. Published by Elsevier B.V.)

The hourly concentrations of eight air pollutants relevant for human health and climate (PM2.5, PM10, O3, NO, NO2, NOx, SO2, and CO) were investigated for 1 year (January 2018 to December 2018) at an urban location of a megacity in the Middle East (Tehran, Iran). The spatial distributions of air pollutants were detected via inter-site correlations and coefficients of divergence. The most likely predominant atmospheric processes and sources were determined by interpreting the seasonal, weekly, and diel patterns of air pollutants and the lagged correlations among pollutants. The effect of meteorological factors upon the air pollutants was evaluated by investigating the relationships with key weather factors. The locations of the possible local sources were identified by integrating atmospheric circulation and air pollutant data through bivariate polar plots and conditional bivariate probability function. Potential transboundary source areas were detected using potential source contribution function and concentration-weighted trajectory. Results show that emission factors, weather, and photochemical processes mainly shape the diel and weekly cycles of air pollutants. Compared to other pollutants, daily cycles of SO2 are quite different among sites and show both bimodal and unimodal patterns. While the WPSCF map for O3 does not show a remarkable pattern, primary gaseous pollutants presented similar distribution patterns with the most potential source areas with high WPSCF values from the western areas. By providing useful information on air pollutants at local and transboundary scales, the current study finally empowers general considerations upon the atmospheric processes and air quality status over the Tehran metropolitan area. [ABSTRACT FROM AUTHOR]

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Fine particulate matter (PM), including PM2.5 in pig houses, has received increasing attention due to the potential health risks associated with PM. At present, most studies have analyzed PM2.5 in Chinese pig houses utilizing natural ventilation. These results, however, are strongly affected by the internal structure and regional environment, thus limiting their applicability to non-mechanically ventilated pig houses. This experiment was carried out in an environmentally controlled pig house. The animal feeding operation and manure management in the house were typical for Southwest China. To reduce the influence of various environmental factors on PM2.5, the temperature and humidity in the house were maintained in a relatively stable state by using an environmental control system. The concentration of PM2.5 in the pig house was monitored, while the biological contents and chemical composition of PM2.5 were analyzed, and feed, manure, and dust particles were scanned using an electron microscope. Moreover, bacterial and fungal contents and some water-soluble ions in PM2.5 were identified. The results showed that the concentration of PM2.5 in the pig house was strongly affected by pig activity, and a phenomenon of forming secondary particles in the pig house was found, although the transformation intensity was low. The concentration of PM2.5 had negative correlations of 0.27 and 0.18 with ammonia and hydrogen sulfide, respectively. Interestingly, a stronger correlation was observed between ammonia and hydrogen sulfide and ammonia and carbon dioxide concentrations (the concentration of ammonia had stronger positive correlations with hydrogen sulfide and carbon dioxide concentrations at +0.44 and +0.59, respectively). The main potential sources of PM2.5 production were feed and manure. We speculate that manure could contribute to the broken, rough, and angular particles that formed the pig house PM2.5 that easily adhered to other components. [ABSTRACT FROM AUTHOR]

Fine particulate matter (PM), including PM2.5 in pig houses, has received increasing attention due to the potential health risks associated with PM. At present, most studies have analyzed PM2.5 in Chinese pig houses utilizing natural ventilation. These results, however, are strongly affected by the internal structure and regional environment, thus limiting their applicability to non-mechanically ventilated pig houses. This experiment was carried out in an environmentally controlled pig house. The animal feeding operation and manure management in the house were typical for Southwest China. To reduce the influence of various environmental factors on PM2.5, the temperature and humidity in the house were maintained in a relatively stable state by using an environmental control system. The concentration of PM2.5 in the pig house was monitored, while the biological contents and chemical composition of PM2.5 were analyzed, and feed, manure, and dust particles were scanned using an electron microscope. Moreover, bacterial and fungal contents and some water-soluble ions in PM2.5 were identified. The results showed that the concentration of PM2.5 in the pig house was strongly affected by pig activity, and a phenomenon of forming secondary particles in the pig house was found, although the transformation intensity was low. The concentration of PM2.5 had negative correlations of 0.27 and 0.18 with ammonia and hydrogen sulfide, respectively. Interestingly, a stronger correlation was observed between ammonia and hydrogen sulfide and ammonia and carbon dioxide concentrations (the concentration of ammonia had stronger positive correlations with hydrogen sulfide and carbon dioxide concentrations at +0.44 and +0.59, respectively). The main potential sources of PM2.5 production were feed and manure. We speculate that manure could contribute to the broken, rough, and angular particles that formed the pig house PM2.5 that easily adhered to other components.

Polybrominated diphenyl ethers (PBDEs) are widely found in the environment owing to the widespread use of brominated flame retardants. In recent years, polybrominated diphenyl ethers have attracted increasing attention because of their harmful effects on human health, especially in children, and have been recognized as significant indoor environmental pollutants. In this study, PBDEs were detected in 80 samples of air, dust, and particulate matter from bedrooms in Hangzhou, indicating that PBDE pollutions in bedrooms occur widely. The median concentration of ∑ 8 PBDEs in dust was 8.54 ng/g, whereas in air and particulate matter was 13.60 pg/m3 and 23.94 pg/m3, respectively. BDE-209 was the main congeners in particles and dust. The mass distribution of atmospheric particles in bedrooms showed a bimodal distribution, mainly in the segments of < 1.1 and 3.3 − 4.7 µm. Through the analysis of typical bedroom materials, the specific PBDEs concentration order was as follows: curtain < wallpaper < mattress < socket panel, with median concentrations of 21.90 µg/g, 45.74 µg/g, 46.31 µg/g and 74.85 µg/g, respectively. The possible sources of PBDEs in residential air, dust, particulate matter was mattress, curtains and mattresses, and mattress and curtains, respectively. Infants have the highest daily exposure dose (DED) for ∑ 5 PBDEs in the air and particulate matter phases, while toddles have the highest DED in dust. The HQ（Hazard Quotient）of infants, toddlers, children, teenagers, and adults were 8.58E-05, 1.06E-04, 4.17E-05, 2.53E-05 and 1.09E-05, respectively, indicating that pollution in bedrooms will not negatively impact human health. However, related studies have shown that children are more likely to be exposed to PBDEs than adults. Therefore, for infants and young children with weaker resistance and long-term family environments, PBDEs pollution may harm their health and growth. [Display omitted] • The health risk of PBDEs to infants and toddlers was greater than that of adults. • The mass distribution of particles in bedrooms showed a bimodal distribution. • The possible source of PBDEs in air, dust, particulate matter was explored. • The HQs indicated that PBDEs pollution in bedrooms were acceptable. • Concentration of PBDEs in dust was the highest. [ABSTRACT FROM AUTHOR]

An intensive measurement campaign was conducted in the coastal city of Xiamen, China to investigate the size distribution and mixing state of the refractory black carbon (rBC) aerosol. The average rBC concentration for the campaign, measured with a ground-based single particle soot photometer (SP2), was 2.3 ± 1.7 μg m − 3 , which accounted for ~ 4.3% of the PM 2.5 mass. A potential source contribution function model indicated that emissions from coastal cities to the southwest were the most important source for the rBC and that shipping traffic was another likely source. The mass size distribution of the rBC particles was mono-modal and approximately lognormal, with a mass median diameter (MMD) of ~ 185 nm. Larger MMDs (~ 195 nm) occurred during polluted conditions compared with non-polluted times (~ 175 nm) due to stronger biomass burning activities during pollution episodes. Uncoated or thinly-coated particles composed the bulk of the rBC aerosol, and on average ~ 31% of the rBC was internally-mixed or thickly-coated. A positive matrix factorization model showed that organic materials were the predominant component of the rBC coatings and that mixing with nitrate increased during pollution conditions. These findings should lead to improvements in the parameterizations used to model the radiative effects of rBC. [ABSTRACT FROM AUTHOR]