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In order to investigate the chemical characteristics and sources of atmospheric heavy metals, PM 2.5 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 PM 2.5 in Beijing during the summer of 2011 and the summer of 2012. In the autumn and winter seasons, PM 2.5 /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 PM 2.5 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.

Thirty non-methane hydrocarbons(NMHCs) samples were collected and analyzed in Foshan City during winter 2014 and summer 2015. The concentrations of NMHCs during the sampling period were 122.30 μg·m -3 and 56.22 μg·m -3 in winter and summer, respectively. The five highest concentration species of NMHCs in winter and summer were in the following order: toluene (25.12 μg·m -3 ), m/p -xylene (13.76 μg·m -3 ), propane (9.17 μg·m -3 ), ethylbenzene (7.25 μg·m -3 ), ethylene (6.77 μg·m -3 ) and toluene (6.18 μg·m -3 ), m/p -xylene (5.21 μg·m -3 ), o -xylene (4.15 μg·m -3 ), β -pinene(3.75 μg·m -3 ), propane (3.29 μg·m -3 ). Compared to 2008, the concentrations of NMHCs have dropped significantly. The proportions of aromatics, alkanes, alkenes and alkynes in NMHCs were 51.20%, 34.70%, 10.04%, 4.05% and 43.93%, 33.99%, 19.20%, 2.88% during winter and summer, respectively. The ratios of NMHCs/NO x were 0.90 and 1.88, indicating that the peak ozone concentrations in Foshan City were controlled by NMHCs during the sampling period, and the emissions of NMHCs should be further strengthened. The propylene equivalent concentration and ozone formation potential were 45.09 μg·m -3 and 40.64 μg·m -3 , 392.77 μg·m -3 and 207.77 μg·m -3 in winter and summer. The m/p -xylene; toluene and m/p -xylene; isoprene had a very important influence on ozone formation potential. The ratios of Benzene/Toluene were 0.15 and 0.20 indicated that industrial process was the main source of NMHCs in Foshan City. Relative to 2008, isopentane didn't belong to the highest concentration of five pollutants for Foshan's NMHCs in this research, indicating the measures to prevent volatile gasoline impact on the environmental quality have achieved remarkable results.

Polycyclic aromatic hydrocarbons (PAHs) are a group of important toxic compounds. In order to detect the pollutional characteristics of atmospheric PAHs in Fine Particulate Matter (PM 2.5 ), a total of 60 PM 2.5 samples were collected in Lanzhou City during the winter of 2012 and summer of 2013. The GC/MS measurement results of the samples demonstrated the averagely total mass concentrations of the most significant 16 homologues of PAHs were (191.79±88.29) ng·m -3 and (8.94±4.34) ng·m -3 in winter and summer respectively, indicating a higher pollution level in winter. In winter, the snowfall was the most important meteorological factor for the decrease of PAHs mass concentration in PM 2.5 . The percentages of PAHs with 4 rings were the highest in both winter (51.40%) and summer (49.94%) in Lanzhou. The percentage of PAHs with 5-6 rings in summer (41.04%) was higher than that in winter (24.94%). However, the percentage of PAHs with 2-3 rings in summer (9.03%) was lower than that in winter (23.67%). Based on the analysis of characteristic ratios, we concluded that the PAHs in atmospheric PM 2.5 in Lanzhou were mainly sourced from coal and vehicle emissions in winter, especially the diesel vehicles. The absolute contributions of all possible PAHs pollution sources were insignificant in summer, with relatively higher contribution from gasoline vehicles.

In order to investigate the influence of the emission reduction measure during the Beijing APEC on the concentrations and pollution characteristics of humic-like substances (HULIS) in atmospheric fine particles, PM₂.₅ samples were collected and analyzed for OCEC, WSOC, HULIS and water-soluble ions. The concentration of HULIS in PM₂.₅ ranged 1 µg · m⁻³-15 µg · m⁻³. HULIS concentrations were 7.99 µg · m⁻³, 5.83 µg · m⁻³ and 7.06 µg · m⁻³ before, during and after APEC, which indicated emission reduction measure had important effect on the reduction of HULlS. The decrease of HULIS during the APEC was significantly faster than those of EC and WSOC, while the increase of HULIS turned out to be much slower than OC, EC, WSOC and PM₂.₅ after the meeting. The proportions of HULIS to PM₂.₅ were 13.60%, 13.59%, 14.02% and 12.22% at four different stages, i. e., whole sampling period, before, during and after the APEC, while HULIS-C/OC and HULIS-C/WSOC were 28.95%, 35.51%, 28.37%, 19.93%; and 52.75%, 59.58%, 51.54%, 45.39%, respectively. HULlS was significantly positively correlated with humidity, while significantly negatively correlated with wind speed. Biomass burning and secondary transformation of VOCs might be two important sources of HULlS in Beijing.

Pollution characteristic and variation trend of atmospheric carbonyls were investigated in November during the 2014 Beijing APEC. Formaldehyde, acetaldehyde and acetone were the dominant carbonyls, accounting for 82.66% of total carbonyls, and especially, formaldehyde accounted for 40.12% of total carbonyls. Atmospheric concentrations of total carbonyls decreased by around 64.10% after the clean air policy was carried out during the Beijing APEC, and the variation trend of carbonyls showed a similar pattern to those of other pollutants like PM₂.₅ during the APEC. Strong correlations (R² of 0.67-0.98) were observed among formaldehyde, acetaldehyde, acetone and total carbonyls during and after the APEC, indicating that they had similar sources; however, poor correlations (R² of -0.11-0.42 and 0.16-0.94, respectively) were observed before the APEC, implying different emission sources for ambient carbonyls. The calculated ratios of C1/C2, C2/C3 and OC/EC indicated that both vehicles and coal emissions were responsible for atmospheric carbonyls before the APEC, and emissions from coal burning were the major contributor to atmospheric carbonyls during and after the APEC, especially after the APEC.

Based on the newly established high-performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD), the saccharides in PM2.5 and PM10 in Beijing from 2011 - 2012 were quantified. Fourteen saccharides were synchronously detected in the aerosols samples in Beijing, which can be divided into three categories, i. e. anhydrosugar, sugar and sugar alcohol. Anhydrosugar, coming from biomass burning, include levoglucosan, mannosan and galactosan. Sugar and sugar alcohol, emitted by the primary biogenic emission, include glucose, fructose, trehalose, arabitol, mannitol, glycerol, threitol, 2-meythltrtols (2-methylthreitol and 2-methylerythrito), xylitol and inositol. The concentrations of monosaccharide anhydrides in summer and autumn were obviously higher than those in spring and winter, while the concentrations of sugar and sugar alcohol in winter were significantly lower than those in other seasons. The results of positive matrix factorization analysis suggested that saccharides compounds in atmospheric PM in Beijing can be derived from biomass burning, suspended soil or dust, isoprene SOA, as well as direct release of airborne fungal spores and pollen.

Based on the EPA method T0-11 and 14/15 for measurement of toxic organics in air samples, fast VOCs detector, Summa canister and DNPH absorbent were used to determine the VOCs concentrations and the compositions in the ambient air of the workshops for different processes as well as the emission concentration in the exhaust gas. In all processes that involved VOCs release, concentrations of total VOCs in the workshops were 0.1-0.5 mg x m(-3), 1.5-2.5 mg x m(-3) and 20-200 mg x m(-3) for casting, cutting and painting respectively. Main compositions of VOCs in those workshops were alkanes, eneynes, aromatics, ketones, esters and ethers, totally over 20 different species. The main compositions in painting workshop were aromatics and ketones, among which the concentration of benzene was 0.02-0.34 mg x m(-3), toluene was 0.24-3.35 mg x m(-3), ethyl benzene was 0.04-1.33 mg x m(-3), p-xylene was 0.13-0.96 mg x m(-3), m-xylene was 0.02-1.18 mg x m(-3), acetone was 0.29-15.77 mg x m(-3), 2-butanone was 0.06-22.88 mg x m(-3), cyclohexene was 0.02-25.79 mg x m(-3), and methyl isobutyl ketone was 0-21.29 mg x m(-3). The VOCs emission from painting process was about 14 t x a(-1) for one single manufacturing line, and 840 t x a(-1) for the whole factory. According to the work flows and product processes, the solvent used during painting process was the main source of VOCs emission, and the exhaust gas was the main emission point.

Total suspended particles (TSP), collected during a typical haze period in Guangzhou, were analyzed for the fatty acids (C12-C30) and low molecular weight dicarboxylic acids (C3-C9) using gas chromatography/mass spectrometry (GC/MS). The results showed that the concentration of total fatty and carboxylic acids was pretty high during the haze episode. The ratios of fatty acids and carboxylic acids in haze to those in normal days were 1.9 and 2.5, respectively. During the episode of the increasing pollution, the fatty acids and carboxylic acids at night (653 ng x m(-3)) was higher than that (487 ng x m(-3)) in days. After that, the level of fatty acids and carboxylic acids in days (412 ng x m(-3)) was higher than that (336 ng x m(-3)) at night. In general, the time-series of fatty acids and carboxylic acids was similar to that of the air particle and carbonaceous species, however, the trend of the ratio of fatty acids and carboxylic acids to organic carbon was opposite to that of air particle and carbonaceous species. This ratio decreased with the increase of the concentration of air particle and after the night of 27th, the ratio increased with the decrease in the concentration of air particle. The results showed that haze pollution had a significant inhibitory effect on the enrichment of fatty and carboxylic acids. Based on the ratio of malonate to succinate (C3/C4), it could be found that primary sources contribute more to the atmospheric fatty and carboxylic acids during the autumn haze pollution periods in Guangzhou.

Volatile Organic Compounds (VOCs) in Foshan City were investigated in December 6 to 30 2008. The concentrations of VOCs in haze days were significantly higher than those in no-haze days. Toluene (68.93 microg x m(-3) +/- 37.78 microg x m(-3)) was the most abundant compound of VOCs in haze days and i-pentane (20.59 microg x m(-3) +/- 14.28 microg x m(-3)) was the most abundant compound in no-haze days, respectively. During haze episodes, the diurnal variations of alkanes and alkynes were not significantly; however, alkenes and aromatic hydrocarbon decreased significantly at noon. During no-haze episodes, the diurnal variations patterns of VOCs were stable. Propylene-equivalent concentrations in haze days were significantly higher than those in no-haze days, toluene was the most abundant compound of Propylene-equivalent concentration in haze days, followed by propene and ethene; propene was the most abundant compound in no-haze days, followed by ethene and 1-butene. High concentration of benzene (18.1 microg x m(-3)) in haze days posed a great health threat to public in Foshan city. Both diurnal variation of VOCs and measured ratios indicated vehicular emissions acted as the main sources of most VOCs and other sources like solvent application also contributed to VOCs (benzene and toluene).

PM2.5 emissions and polycyclic aromatic hydrocarbons (PAHs) in PM2.5 of pure biodiesel derived from different feedstocks were investigated and compared with diesel fuel. B100-1 (soyabean oil derived), B100-2 (waste oil derived) and diesel fuel were tested on a diesel engine bench at four operating conditions, including two steady speeds of different loads. The fine particles were collected by fiber quartz filter and particle phase PAHs were analyzed by GC-MS. Compared with diesel fuel, biodiesel decreased PM2.5 emission rates with a maximal reduction rate of 37.3% at operating modes of high loads, while increased PM2.5 emission rates at low loads. PAHs emission rates from biodiesel decreased at all tested modes, with a maximal reduction rate of 77.6%. The emission rates of PM2.5 and PAHs of B100-2 were 14.7% and 17.8% times of B100-1. Low molecular weight PAHs dominated in the emission of three fuels with phenanthrene as maxima and 2-ring and 3-ring PAHs accounted for more than 50% of the total PAHs. Toxic equivalence of PAHs emissions of biodiesel was decreased greatly compared with that of diesel.

The air quality in Beijing and surrounding area is influenced by local emission and regional transport. To study the characteristics of regional pollution, PM (particulate matter) samples were collected simultaneously at 4 sites including Tsinghua University (TH) and Miyun reservoir (MY) in Beijing, Renqiu (RQ, Hebei Province), and Shangdu (SD, Inner Mongolia) during August, 2007, and temporal/spatial distributions of PM2.5 mass concentrations along with 22 elements in TSP were characterized. PM2.5 mass concentrations were quite different at 4 sites, following the sequence as RQ > TH > MY > SD. The highest concentrations of pollution-derived elements S, Zn, Pb, Cu, As, Sb, Ni, Cd, In, Se were found in RQ, showing the most intensive anthropogenic influence around this region, and their lowest variation indicated that the pollution mostly came from local sources. Controlled by the meteorological factors, highest daily variations of these elements were found at SD with relative lower concentrations. The correlation coefficients of S, Pb, Cd, In, As, Zn concentrations between TH and MY were all higher than 0.70, which implies similar sources for these elements at the 2 sites in Beijing. At the beginning and the end of the Sawtooth pollution episode in Beijing, concentrations of most elements in Miyun were comparable with the lowest concentrations at Shangdu observed during the sampling period, which means Miyun could well represent the regional characteristics of clean air mass from the northwest. Uniform spatial distribution of high sulfate was found (about 10 microg/m3) at the peaks of Sawtooth episode, which implies the important contribution from secondary aerosol during the regional pollution. Variable sources of PM at each site and their regional influence were discussed based on the different characteristics of elemental enrichment factors.

The purpose of this study is to investigate the effect of fog processes on the physical and chemical properties of aerosol particles in an urban atmosphere. Atmospheric particles were collected in the urban atmosphere of Beijing during fog and non-fog episodes. The morphology, size and elemental composition of individual particles were characterized using a scanning electron microscope (SEM) equipped with an energy dispersive X-ray spectrometer (EDX). EDX analysis showed that elongated particles were composed of Ca-K-S or Ca-S, and most sub-round particles contained sulfur. Large amounts of elongated and sub-round particles were identified in the samples collected during fog episodes, and they were rarely detected in the samples collected during non-fog episodes. This suggests that the high relative humidity in the fogs facilitated the formation of elongated and sub-round particles. Number concentrations of particles larger than 0.2 microm were about 5 to 8 times higher during the fog episodes. In addition, a new mode around 0.4 microm appeared in number size distribution of particles during the fog episodes. These results indicate that heterogeneous reactions in the fogs could greatly change the chemical and physical properties of particles.

Total suspended particulates (TSP) samples were collected from Sep., 2003 to Jul., 2004 in Beijing, and 15 kinds of PAHs, ranging from 3 to 7 rings were analyzed. The maximum concentrations sigma PAHs and BaP were 705 ng/m3 and 52 ng/m3 respectively. Average sigma PAHs concentrations in four seasons were 46 ng/m3, 16 ng/m3, 52 ng/m3 and 268 ng/m3 respectively; and the average BaP concentrations in four seasons were 2.8 ng/m3, 0.23 ng/m3, 3.3 ng/m3, 16 ng/m3 respectively. Regarding to the meteorological parameters, precipitation distinctly lowered the concentration; in heating period, PAHs concentrations fall with the temperature goes up, but there is no obvious relation between concentration and temperature in non-heating period; the increase of wind speed level causes the decrease of PAH concentrations in the heating period, but relation between PAH concentrations and wind speed varied with aromatic rings of PAHs and levels of wind speed in the non-heating period.

Taking magnesium oxide slurry as absorption solution, the simulation of bubbling absorption process of mixed SO2 gases was observed in laboratory. Experiment results show that with a high efficiency and stable situation, acidification of absorbing solution was caused by HSO3-; the acidification trend was in accordance with the pattern of hydrolyzing of SO2, pH changes slowly at high pH value with SO3(2-) and rapidly at low value with HSO3-. The experiments also show the insensitive effect of liquid temperature on the high desulphurization efficiency. With relatively high dissolution rate and oxidizability of MgSO3 as well as the high solubility of MgSO4, the desulphurization efficiency utilization of MgO. Industrial experiment of FGD of coal-fired boiler showed that by recycling absorbing liquid could be raised to the concentration of MgSO4 to the saturation concentration at the operation temperature (40-50 degrees C) without any adverse effects on FGD efficiency. Refinement and enrichment of active substance could promote the desulphurization process, thus showed the availability of technical and economy feasibility of recovery technology.

To understand the concentration levels and temporal variations of the mineral component of PM2.5 in the ambient air of Beijing, weeklong samples were simultaneously collected for one year at Qinghuayuan and Chegongzhuang. The concentrations of five major crustal elements Al, Si, Ca, Mg, and Fe exhibited similar significant weekly variations, with their maximum values in the week of a serious dust event in the spring of 2000. Obvious seasonal pattern was also found for these elements, indicating different influences on fine mineral particles from the source emissions and meteorology in different seasons. Soil dust concentration increased from a low level in summer to the peak value (21.1 microg x m(-3)) in spring, suggesting that frequent dust events made a significant contribution to fine soil dust. A large number of construction activities in Beijing substantially increased the loading of fine calcium-bearing particles, and their emissions thus need to be further controlled.