[Pollution Characteristics and Source Apportionment of Fine Particulate Matter in Autumn and Winter in Puyang, China].

As one of the air pollution transmission channels around the beijing-Tianjin-Hebei region, Puyang frequently suffer from severe airpollution in autumn and winter. In order to study the characteristics and main sources of fine particulate matter during these periods, manual membrane sampling of PM2.5 was conducted at three national control sites from October 15, 2017, to January 13, 2018. Chemical composition analysis was conducted and, combined with a PMF receptor model, source analysis of the fine particles was also undertaken. The results show that the average mass concentration of PM2.5 in Puyang was 94.16 µg·m-3 in the autumn and winter of 2017, and Pushuihe station was the most polluted site. During the heating season, the three control stations all recorded the frequent occurrence of severe and serious pollution events, while the frequency of mild pollution events decreased. When heavy pollution events occurred, the concentrations of NO2 and CO increased significantly. The main components of PM2.5 were water-soluble ions (52.33%), OCEC (25.32%), and crustal elements (0.08%). The concentrations of NO3- were high while the concentrations of SO42- were low. When heavy pollution occurred, the concentrations of water-soluble ions, OC, EC, and K in PM2.5 increased significantly, while the concentrations of crustal elements decreased. During the sampling period, the conversion ratios of sulfur and nitrogen in Puyang were high and atmospheric oxidation was strong. The transformation of sulfur and nitrogen promoted the occurrence of heavy pollution. Emissions of NOx, CO, and VOCs were higher in Puyang in 2017, and the source apportionment results showed that the main sources of PM2.5 in autumn and winter were secondary inorganic salts (37%), industrial sources (16%), secondary organic aerosol (SOA, 14%), biomass combustion (12%), mobile sources (9%), coal burning (7%), and dust (4%). Secondary transformation played an important role in the development of heavy pollution events in Puyang. It is necessary to focus on the control of emissions from industrial sources, biomass combustion, moving source, and civil coal combustion.

Source apportionment of fine particulate matter organic carbon in Shenzhen, China by chemical mass balance and radiocarbon methods.

Chemical mass balance (CMB) modeling and radiocarbon measurements were combined to evaluate the sources of carbonaceous fine particulate matter (PM2.5) in Shenzhen, China during and after the 2011 summer Universiade games when air pollution control measurements were implemented to achieve air quality targets. Ambient PM2.5 filter samples were collected daily at two sampling sites (Peking University Shenzhen campus and Longgang) over 24 consecutive days, covering the controlled and uncontrolled periods. During the controlled period, the average PM2.5 concentration was less than half of what it was after the controls were lifted. Organic carbon (OC), organic molecular markers (e.g., levoglucosan, hopanes, polycyclic aromatic hydrocarbons), and secondary organic carbon (SOC) tracers were all significantly lower during the controlled period. After pollution controls ended, at Peking University, OC source contributions included gasoline and diesel engines (24%), coal combustion (6%), biomass burning (12.2%), vegetative detritus (2%), biogenic SOC (from isoprene, α-pinene, and ß-caryophyllene; 7.1%), aromatic SOC (23%), and other sources not included in the model (25%). At Longgang after the controls ended, similar source contributions were observed: gasoline and diesel engines (23%), coal combustion (7%), biomass burning (17.7%), vegetative detritus (1%), biogenic SOC (from isoprene, α-pinene, and ß-caryophyllene; 5.3%), aromatic SOC (13%), and other sources (33%). The contributions of the following sources were smaller during the pollution controls: biogenic SOC (by a factor of 10-16), aromatic SOC (4-12), coal combustion (1.5-6.8), and biomass burning (2.3-4.9). CMB model results and radiocarbon measurements both indicated that fossil carbon dominated over modern carbon, regardless of pollution controls. However, the CMB model needs further improvement to apportion contemporary carbon (i.e. biomass burning, biogenic SOC) in this region. This work defines the major contributors to carbonaceous PM2.5 in Shenzhen and demonstrates that control measures for primary emissions could significantly reduce secondary organic aerosol (SOA) formation.

Source profiles of particulate organic matters emitted from cereal straw burnings.

Cereal straw is one of the most abundant biomass burned in China but its contribution to fine particulates is not adequately understood. In this study, three main kinds of cereal straws were collected from five grain producing areas in China. Fine particulate matters (PM2.5) from the cereal straws subjected to control burnings, both under smoldering and flaming status, were sampled by using a custom made dilution chamber and sampling system in the laboratory. Element carbon (EC) and organic carbon (OC) was analyzed. 141 compounds of organic matters were measured by gas chromatography-mass spectrum (GC-MS). Source profiles of particulate organic matters emitted from cereal straw burnings were obtained. The results indicated that organic matters contribute a large fraction in fine particulate matters. Levoglucosan had the highest contributions with averagely 4.5% in mass of fine particulates and can be considered as the tracer of biomass burnings. Methyloxylated phenols from lignin degradation also had high concentrations in PM2.5, and contained approximately equal amounts of guaiacyl and syringyl compounds. beta-Sitostrol also made up relatively a large fraction of PM2.5 compared with the other sterols (0.18%-0.63% of the total fine particle mass). Normal alkanes, PAHs, fatty acids, as well as normal alkanols had relatively lower concentrations compared with the compounds mentioned above. Carbon preference index (CPI) of normal alkanes and alkanoic acids showed characteristics of biogenic fuel burnings. Burning status significantly influenced the formations of EC and PAHs. The differences between the emission profiles of straw and wood combustions were displayed by the fingerprint compounds, which may be used to identify the contributions between wood and straw burnings in source apportionment researches.

[Chemical Characteristics and Sources of Heavy Metals in Fine Particles in Beijing in 2011-2012].

In order to investigate the chemical characteristics and sources of atmospheric heavy metals, PM2.5 samples were collected every three days during the summer of 2011 and summer of 2012. The samples were analyzed for Li, V, Cr, Mn, Co, Cu, Zn, As, Se, Ti, Ga, Ni, Sr, Cd, In, Ba, Tl, Pb, Bi, and U by ICP-MS, with an emphasis on seven major heavy metal elements (Zn, Pb, Mn, Cu, As, V, and Cr). The concentrations of Zn, Pb, Mn, Cu, As, V, and Cr were (331.30±254.52), (212.64±182.06), (85.96±47.00), (45.19±27.74), (17.13±19.02), (4.92±3.38), and (9.04±7.84) ng·m-3 in PM2.5 in Beijing during the summer of 2011 and the summer of 2012. In the autumn and winter seasons, PM2.5/heavy metal pollution is more severe than in spring and summer, which may be related to the increase in coal combustion used for heating in autumn and winter in Beijing. Haze pollution enhances the concentrations of seven heavy metals in PM2.5 in Beijing and the enhancement shows seasonal variations. The source analysis suggested that dust (including building dust and road dust) and coal combustion might be two most important sources of heavy metals in Beijing, and transport and other industrial sources cannot be ignored.

[Bioindicating function of sulfur in Haplocladium under heavy metals pollution by SRXRF and XANES].

Haplocladium was cultivated in a special prepared nutrient medium containing different concentrations of Pb, Fe and Cr in laboratory. The sulfur content in moss was measured by synchrotron radiation X-ray fluorescence (SRXRF), and the percentage of various oxidation states of sulfur was analyzed by X-ray absorption near-edge structure (XANES) spectrum. The results show that the sulfur absorption increases under exposure to heavy metal ions of Pb and Fe, but it decreases under exposure to 400 mg/L Pb and 200 mg/L Fe. When Haplocladium was cultivated for 15 days, under the stress of 100 mg/L Pb, the relative content of low oxidation states sulfur increases from 17.8% to 23.6% and the sulfate sulfur decreases from 56.3% to 51.2%. Under the stress of 400 mg/L Pb, the relative content of low oxidation state sulfur increases from 17.8% to 24.8%, and the sulfate sulfur decreases from 56.3% to 48.4%. Under heavy metal exposure, the total relative content of low oxidation states sulfur such as cystine, cysteine, methionine and glutathione increases, and the relative content of sulfate sulfur apparently decreases. All these results indicate that the changing characteristics of sulfur content and oxidation states percentage in sulfur assimilation process under heavy metal exposure can be used as a bioindicator of heavy metal pollution.

[Comprehensive study of lead pollution in atmospheric aerosol of Shanghai].

The lead contamination, lead species and source assignment were studied by a combination of several analytical techniques such as Proton-induced X-ray emission analysis (PIXE), Proton microprobe (micro-PIXE), Inductively coupled plasma-mass spectrometry (ICP-MS) and extended X-ray absorption fine structure (EXAFS) techniques. The results indicate that the lead concentration in the air of Shanghai gradually decreased over the last years. The atmospheric lead concentration of PM10 in the winter of 2002 was 369 ng x m(-3), which had declined by 28% in 2001, and in the winter of 2003 it decreased further to 237 ng x m(-3). The main lead species in the samples collected in the winter of 2003 were probably PbCl2, PbSO4 and PbO. The source apportionment was calculated in terms of the combination of lead isotope ratios and lead mass balance method, assisted by single particle analysis with micro-PIXE and pattern recognition. The results suggest that the major contributors of atmospheric lead pollution in Shanghai are the coal combustion dust; the metallurgic dust and vehicle exhaust particles, with a contribution around 50%, 35% and 15%, respectively. It probably is the first time to give a city a quantitative estimation of lead pollution contribution from emission sources. The influence from leaded gasoline was still present in the atmosphere by four or five years after the phasing out of leaded gasoline.