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In order to understand the compositions characteristics of particulate matter with aerodynamic diameter less than 2.5 μm (PM2.5) fraction in road dust (RD2.5) of oasis cities on the edge of Tarim Basin, 30 road dust (RD) samples were collected in Kashi, Cele, and Yutian in the spring, 2018, and RD2.5 was collected using the resuspension approach. Eight water-soluble ions, 39 trace elements and 8 fractions of carbon-containing species in PM2.5 were analyzed. Ca2+ and Ca were the most abundant ions and elements in RD2.5 (7.1% and 9.5%). Cl- in RD2.5 was affected not only by attributed to saline-alkali soils in oasis cities of the Tarim Basin and dust from Taklimakan Desert but also by human activities. Moreover, the organic carbon/elemental carbon (OC/EC) ratio indicated that carbon components in RD2.5 in Cele town mainly come from fossil fuel combustion, while those in Yutian and Kashi mainly come from biomass combustion. It is noteworthy that high Ca in RD2.5 was seriously affected by anthropogenic emissions, and high Na and K contents in RD2.5 could be derived from soil and desert dust. It was estimated that Cd, Tl, Sn and Cr were emitted from anthropogenic emissions using the enrichment factor. The coefficients of divergence (COD) result indicated that the influence of local emission on road dust emission is greater than that of long-distance transmission. This study is the first time to comprehensively analyze the chemical characteristics of road dust in oasis cities, and the results provides the sources of road dust at the margin of Tarim Basin.

To evaluate the potential benefits of biomass use for air pollution control, this paper identified and quantified the emissions of major reactive organic compounds anticipated from biomass-fired industrial boilers. Wood pellets (WP) and straw pellets (SP) were burned to determine the volatile organic compound emission profiles for each biomass-boiler combination. More than 100 types of volatile organic compounds (VOCs) were measured from the two biomass boilers. The measured VOC species included alkanes, alkenes and acetylenes, aromatics, halocarbons and carbonyls. A single coal-fired boiler (CB) was also studied to provide a basis for comparison. Biomass boiler 1 (BB1) emitted relatively high proportions of alkanes (28.9%–38.1% by mass) and alkenes and acetylenes (23.4%–40.8%), while biomass boiler 2 (BB2) emitted relatively high proportions of aromatics (27.9%–29.2%) and oxygenated VOCs (33.0%–44.8%). The total VOC (TVOC) emission factors from BB1 (128.59–146.16 mg/kg) were higher than those from BB2 (41.26–85.29 mg/kg). The total ozone formation potential (OFP) ranged from 6.26 to 81.75 mg/m3 with an average of 33.66 mg/m3 for the two biomass boilers. The total secondary organic aerosol potential (SOAP) ranged from 61.56 to 211.67 mg/m3 with an average of 142.27 mg/m3 for the two biomass boilers. The emission factors (EFs) of TVOCs from biomass boilers in this study were similar to those for industrial coal-fired boilers with the same thermal power. These data can supplement existing VOC emission factors for biomass combustion and thus enrich the VOC emission inventory.

In 2013, China issued "Air Pollution Prevention and Control Action Plan (Action Plan)" to improve air quality. To assess the benefits of this program in Beijing-Tianjin-Hebei (BTH) region, where the density of population and emissions vary greatly, we simulated the air quality benefit based on BenMAP to satisfy the Action Plan. In this study, we estimate PM2.5 concentration using Voronoi spatial interpolation method on a grid with a spatial resolution of 1×1km2. Combined with the exposure-response function between PM2.5 concentration and health endpoints, health effects of PM2.5 exposure are analyzed. The economic loss is assessed by using the willingness to pay (WTP) method and human capital (HC) method. When the PM2.5 concentration falls by 25% in BTH and reached 60μg/m3 in Beijing, the avoiding deaths will be in the range of 3175 to 14051 based on different functions each year. Of the estimated mortality attributable to all causes, 3117 annual deaths were due to lung cancer, 1924 - 6318 annual deaths were due to cardiovascular, and 343 - 1697 annual deaths were due to respiratory. Based on WTP, the estimated monetary values for the avoided cases of all cause mortality, cardiovascular mortality, respiratory mortality and lung cancer ranged from 1110 to 29632, 673 to 13325, 120 to 3579, 1091 to 6574 million yuan, respectively. Based on HC, the corresponding values for the avoided cases of these four mortalities were 267 to 1178, 161 to 529, 29 to 143 and 261 million yuan, respectively.

Daily PM2.5 (particulate matter with an aerodynamic diameter of below 2.5 μm) mass concentrations were measured by gravimetric analysis in Chinese Research Academy of Environmental Sciences (CRAES), in the northern part of the Beijing urban area, from December 2013 to April 2015. Two pairs of Teflon (T1/T2) and Quartz (Q1/Q2) samples were obtained, for a total number of 1352 valid filters. Results showed elevated pollution in Beijing, with an annual mean PM2.5 mass concentration of 102 μg/m(3). According to the calculated PM2.5 mass concentration, 50% of our sampling days were acceptable (PM2.575 μg/m(3)), 30% had slight/medium pollution (75-150 μg/m(3)), and 7% had severe pollution (250 μg/m(3)). Sampling interruption occurred frequently for the Teflon filter group (75%) in severe pollution periods, resulting in important data being missing. Further analysis showed that high PM2.5 combined with high relative humidity (RH) gave rise to the interruptions. The seasonal variation of PM2.5 was presented, with higher monthly average mass concentrations in winter (peak value in February, 422 μg/m(3)), and lower in summer (7 μg/m(3) in June). From May to August, the typical summer period, least severe pollution events were observed, with high precipitation levels accelerating the process of wet deposition to remove PM2.5. The case of February presented the most serious pollution, with monthly averaged PM2.5 of 181 μg/m(3) and 32% of days with severe pollution. The abundance of PM2.5 in winter could be related to increased coal consumption for heating needs.

To investigate the levels of exposure to particulate-bound polycyclic aromatic hydrocarbon (PAR) and to estimate the risk these levels pose to traffic assistants (TAs) in Tianjin (a megacity in North China), a measurement campaign (33 all-day exposure samples, 25 occupational-exposure samples and 10 indoor samples) was conducted to characterize the TAs' exposure to PAHs, assess the cancer risk and identify the potential sources of exposure. The average total exposure concentration of 14 PAHs was approximately 2871 +/- 928 ng/m(3) (on-duty), and 1622 +/- 457 ng/m(3) (all-day). The indoor PAHs level was 1257 +/- 107 ng/m(3). After 8000 Monte Carlo simulations, the cancer risk resulting from exposure to PAHs was found to be approximately 1.05 x 10(-4). A multivariate analysis was applied to identify the potential sources, and the results showed that, in addition to vehicle exhaust, coal combustion and cooking fumes were also another two important contributors to personal PAR exposure. The diagnostic ratios of PAR compounds agree with the source apportionment results derived from principal component analysis.

A new air exchange rate (AER) monitoring method using continuous CO2 sensors was developed and validated through both laboratory experiments and field studies. Controlled laboratory simulation tests were conducted in a 1-m(3) environmental chamber at different AERs (0.1-10.0 hr(-1)). AERs were determined using the decay method based on box model assumptions. Field tests were conducted in classrooms, dormitories, meeting rooms and apartments during 2-5 weekdays using CO2 sensors coupled with data loggers. Indoor temperature, relative humidity (RH), and CO2 concentrations were continuously monitored while outdoor parameters combined with on-site climate conditions were recorded. Statistical results indicated that good laboratory performance was achieved: duplicate precision was within 10%, and the measured AERs were 90%-120% of the real AERs. Average AERs were 1.22, 1.37, 1.10, 1.91 and 0.73 hr(-1) in dormitories, air-conditioned classrooms, classrooms with an air circulation cooling system, reading rooms, and meeting rooms, respectively. In an elderly particulate matter exposure study, all the homes had AER values ranging from 0.29 to 3.46 hr(-1) in fall, and 0.12 to 1.39 hr(-1) in winter with a median AER of 1.15.

Aliphatic hydrocarbons (n-alkanes) associated with fine particulate matter were determined in the ambient air of urban, industrial and coastal areas in Tianjin, China, where intensive coal burning for industrial and domestic purpose takes place. n-Alkane homologues from C12 to C35 were quantifiable in all samples with C20-C31 being the most abundant species. Average concentrations of the total n-alkanes were 148.7, 250.1 and 842.0 ng/m3 in July, April and January, respectively. Seasonal variations were mainly attributed to ambient temperature changes and coal combustion for residential heating. Among the three studied areas, the highest levels of n-alkanes were observed in the industrial complex in winter and spring, but in summer the coastal alkane concentration moved up to the highest. A mono-modal distribution for n-alkanes was observed in spring and summer with odd carbon number predominance and a maximum centered at C27-C31, suggesting the release of plant wax into the atmosphere. The bimodal distribution with maxima at C22 and C26 observed in winter indicated a substantial influence of fossil fuel sources. All the CPIs (CPI1, CPI2, CPI3) values, varying between 0.64 and 1.97, indicated the influence of anthropogenic emissions on fine organic aerosols. The estimated contributions of plant wax to total n-alkanes were on average of 12.9%, 19.1% and 26.1% for winter, spring and summer, respectively.

Land use regression (LUR) model was employed to predict the spatial concentration distribution of NO 2 and PM 10 in the Tianjin region based on the environmental air quality monitoring data. Four multiple linear regression (MLR) equations were established based on the most significant variables for NO 2 in heating season ( R 2 = 0.74), and non-heating season ( R 2 = 0.61) in the whole study area; and PM 10 in heating season ( R 2 = 0.72), and non-heating season ( R 2 = 0.49). Maps of spatial concentration distribution for NO 2 and PM 10 were obtained based on the MLR equations (resolution is 10 km). Intercepts of MLR equations were 0.050 (NO 2 , heating season), 0.035 (NO 2 , non-heating season), 0.068 (PM 10 , heating season), and 0.092 (PM 10 , non-heating season) in the whole study area. In the central area of Tianjin region, the intercepts were 0.042 (NO 2 , heating season), 0.043 (NO 2 , non-heating season), 0.087 (PM 10 , heating season), and 0.096 (PM 10 , non-heating season). These intercept values might imply an area's background concentrations. Predicted result derived from LUR model in the central area was better than that in the whole study area. R 2 values increased 0.09 (heating season) and 0.18 (non-heating season) for NO 2 , and 0.08 (heating season) and 0.04 (non-heating season) for PM 10 . In terms of R 2 , LUR model performed more effectively in heating season than non-heating season in the study area and gave a better result for NO 2 compared with PM 10 .

Source apportionment studies of TSP (atmospheric particulate matter with aerodynamic diametersor = 100 microm) and PM10 (atmospheric particulate matter with aerodynamic diametersor = 10microm) have revealed that soil dust is an important source of these particulates in China. In this study, the contamination of soil dust was assessed through the use of a geoaccumulation index (I(geo)). The mass concentration profiles of 17 elements (Na, Mg, Al, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Br, Ba, and Pb) were established for urban soil dusts. Geochemical compositions of soils from 15 cities were used to represent background urban soil compositions. The results of this study indicated that a number of cities are severely polluted by particulates containing Ca, Cr, Ni, and Cu in both size fractions (TSP and PM10). Contamination with Zn, Pb, Co, and Br was moderate to severe (I(geo)2). The Al and Fe concentrations were not high enough for them to be considered contaminants.