To estimate the biogenic volatile organic compound (BVOC) emissions in China, this study collected data on vegetation volume, production and distribution, converted into leaf biomass and then used BVOC emission model. In 2003, the annual BVOC emission in China was 12.83 Tg, composed of 7.45 Tg isoprene, 2.23 Tg monoterpenes, and 3.14 Tg other VOCs (OVOCs). Emissions varied significantly among plant species, with contributions ordered as follows: forests > shrubs > crops > grasslands. Southern and northeastern China were the main sources of BVOC emissions. Significant seasonal variation was found with summer contributing the most.

Multi-year inventories of anthropogenic black carbon emissions, including both fuel consumption and biomass open burning, at a high spatial resolution of 0.25°×0.25° have been constructed in China using GIS methodology for the period 1980–2009, based on official statistical data and time-varying emission factors. Results show that black carbon emissions increased from 0.87 Tg in 1980 to 1.88 Tg in 2009 with a peak in about 1995, and had been continually increasing in the first decade of the 21 century. Residential contribution to the total BC emissions declined from 82.03% in 1980 to 42.33% in 2009 at a continuous diminishing trend, but had always been the dominant contributor in China. While contributions from industry and transportation sectors had increased notably. BC emissions were mainly concentrated in the central eastern districts, the three northeastern provinces and the Sichuan Basin, covering 22.30% of China's territory, but were responsible for 43.02%, 50.47%, 50.69% and 54.30% of the national black carbon emissions in 1985, 1995, 2005 and 2009, respectively. Besides, China made up 70%–85% of BC emissions in East Asia, half of the emissions in Asia, and accounted for averagely 18.97% of the global BC emissions during the estimation period.

Visibility in the Sichuan Basin of China has long been at low levels due to topographic features and high pollution. This study produced trend maps tracking the spatial patterns and temporal trends of visibility in the Sichuan Basin based on 38 years of daily visibility data. Three major fluctuations in the visibility pattern were found: a period of decreasing visibility from 1973 to 1990, a period in which the visibility pattern remained stable from 1991 to 2000, and a period of the visibility recovery from 2001 to 2010. Data from 12 stations in the Sichuan Basin were further analyzed using cumulative percentiles, ridit analysis and days of visibility > 19 km and < 10 km. Hazy conditions were most prevalent in Chengdu and Chongqing, which had visibility less than 10 km and more than 200 low visibility days per year after 2000. Fengjie, Youyang and Langzhong showed consistent declines in visibility and in the number of days with visibility > 19 km whereas Liangping, Nanchong and Wanyuan experienced relatively small decreases but much variation. Upturn trends were observed in Daxian, Mianyang, Ya'an and Yibin after 1995. Although the specific trends differed among stations, a general trend of reduced visibility was found over Sichuan basin. Median visibilities in 2000s were approximately 4 to 38% lower than those during the 1970s, indicating that more efforts are needed for recovery. This study represents the first comprehensive analysis of long-term visibility patterns in the Sichuan Basin.

A more accurate emission inventory of Black Carbon (BC) from China in 2000 was established based on county-level statistical data and recently published emission factors (EFs) from local measurements, which were further gridded at 0.5° × 0.5°. A comprehensive database for BC emission factors was compiled for main anthropogenic sources. BC emissions from China in 2000 were estimated to be 1228.52 Gg under normal operating conditions, and would increase to 2136.53 Gg if failures in control devices and combustion were considered. Spatial distribution of national BC emissions and emissions from different sources were determined; districts with extraordinarily high emissions cover 18.0% of China’s territory but generated 69.14% of the total emissions. Separate EFs were developed for each vehicle type fueled with gasoline or diesel; both the absolute value and relative share of BC emissions from vehicles in this work were higher than those in previous reports, suggesting that previous studies which did not differentiate vehicle types may have underestimated vehicle emissions.

Multi-year inventories of carbonaceous aerosol emissions from biomass open burning at a high spatial resolution of 0.5° × 0.5° have been constructed in China using GIS methodology for the period 1990–2005. Black carbon (BC) emissions have increased by 383.03% at an annual average rate of 25.54% from 14.05 Gg in 1990 to 67.87 Gg in 2005; while organic carbon (OC) emissions have increased by 365.43% from 57.37 Gg in 1990 to 267.00 Gg in 2005. Through the estimation period, OC/BC ratio for biomass burning was averagely 4.09, suggesting that it was not the preferred control source from a climatic perspective. Spatial distribution of BC and OC emissions were similar, mainly concentrated in three northeastern provinces, central provinces of Shandong, Jiangsu, Anhui and Henan, and southern provinces of Guangxi, Guangdong, Hunan and Sichuan basin, covering 24.89% of China’s territory, but were responsible for 63.38% and 67.55% of national BC and OC emissions, respectively.

An integrated urban air quality modeling system was applied to assess the effects of a short-term odd-even day traffic restriction scheme (TRS) on traffic-related air pollution in the urban area of Beijing (UAB) before, during and after the 2008 Olympic Games. Using traffic flow data retrieved from an on-line traffic monitoring system, concentration levels of CO, PM10, NO2 and O3 on the 2nd, 3rd, 4th Ring Roads (RR) and Linkage Roads (LRs), the main roads distributed around the UAB, were predicted for the pre- (10th-19th, July), during- (20th July-20th September) and post-TRS (21st-30th, September) periods. A widely used statistical framework for model evaluation was adopted, the dependences of model performance on time-of-the-day and on wind direction were investigated, and the model predictions turned out reasonably satisfactory. Results showed that daily average concentrations on the 2nd, 3rd, 4th RR and LRs decreased significantly during the TRS period, by about 35.8, 38.5, 34.9 and 35.6% for CO, about 38.7, 31.8, 44.0 and 34.7% for PM10, about 30.3, 31.9, 32.3 and 33.9% for NO2, and about 36.7, 33.0, 33.4 and 34.7% for O3, respectively, compared with the pre-TRS period. Hourly average concentrations were also reduced significantly, particularly for the morning and evening peaks for CO and PM10, for the evening peak for NO2, and for the afternoon peak for O3. Consequently, both the daily and hourly concentration level of CO, PM10, NO2 and O3 conformed to the China National Ambient AirQuality Standards Grade II during the Games. In addition, notable reduction of concentration levels was achieved in different regions of Beijing, with the traffic-related air pollution in the downwind northern and western areas relieved most significantly. The TRS policy was therefore effective in alleviating traffic-related air pollution and improving short-term air quality in Beijing during the Games.

In order to design more reasonable and effective acid deposition control policies, the critical load function (CLF) was established and a two-dimensional critical load function figure was drawn based on the steady-state mass balance (SMB) method. The figure could be divided into five different regions: critical load region (non-control region), S deposition control region, N deposition control region, S and N deposition selective control region and S and N deposition simultaneous control region. According to the region into which the deposition point fell, we could choose the corresponding control approach. With further consideration of high base cation deposition (BCdep) in China, a three-dimensional critical load function surface could be drawn by taking BCdep as a variable. As a case study, critical loads of sulfur and nitrogen for the lateritic red earth in Guangzhou were calculated with current deposition data, vegetation data and soil data obtained by field sampling and laboratory analysis. Results showed that the current deposition point fell into the critical load region and a 75% reduction in BCdep caused the deposition point falling into S deposition control region, which indicated the importance of controlling sulfur deposition. While taking the critical load of nutrient nitrogen into account, the current deposition point fell into N deposition control region and with the reduction of BCdep, the deposition point entered S and N deposition simultaneous control region, which meant sulfur and nitrogen deposition should be controlled at the same time.

In order to investigate the air quality and the abatement of traffic-related pollution during the 2008 Olympic Games, we select 12 avenues in the urban area of Beijing to calculate the concentrations of PM10, CO, NO2 and O3 before and during the Olympic traffic controlling days, with the OSPM model.

This study explores a bibliometric approach to quantitatively assessing current research trends on volatile organic compounds, by using the related literature in the Science Citation Index (SCI) database from 1992 to 2007. The articles acquired from such literature were concentrated on the general analysis by scientific output, the research performances by countries, institutes, and collaborations, and the research trends by the frequency of author keywords, words in title, words in abstract, and keywords plus. Over the past years, there had been a notable growth trend in publication outputs, along with more participation and collaboration of countries and institutes. Research collaborative papers had shifted from the national inter-institutional to the international collaboration. Benzene, toluene, and formaldehyde were the three kinds of VOCs concerned mostly. Detection and removing, especially by adsorption and oxidation, of VOCs were to be the orientation of all VOCs research in the next few years.

Emission inventories of sixty-seven speciated non-methane volatile organic compounds (NMVOC) from on-road vehicles in China were estimated for the period of 1980–2005, using seven NMVOC emission profiles, which were summarized based on local and international measurements from published literatures dealing with specific vehicle categories running under particular modes. Results show an exponential growth trend of China's historical emissions of alkanes, alkenes, alkines, aromatics and carbonyls during the period of 1980–2005, increasing from 63.9, 39.3, 6.9, 36.8 and 24.1 thousand tons, respectively, in 1980 to 2778.2, 1244.5, 178.7, 1351.7 and 406.0 thousand tons, respectively, in 2005, which coincided well with China's economic growth. Emission inventories of alkenes, aromatics and carbonyls were gridded at a high resolution of 40 km×40 km for air quality simulation and health risk evaluation, using the geographic information system (GIS) methodology. Spatial distribution of speciated NMVOC emissions shows a clear difference in emission densities between developed eastern and relatively underdeveloped western and inland China. Besides, the appearance and expansion of high-emission areas was another notable characteristic of spatial distribution of speciated NMVOC emissions during the period. Emission contributions of vehicle categories to speciated NMVOC groups showed annual variation, due to the variance in the provincial emissions and in the relative fractions of the seven emission profiles adopted at the provincial level. Highly reactive and toxic compounds accounted for high proportions of emissions of speciated NMVOC groups. The most abundant compounds were isopentane, pentane and butane from alkanes; ethene, propene, 2-methyl-2-butene and ethyne from alkenes and alkines; benzene, toluene, ethylbenzene, o-xylene, and m,p-xylene (BTEX) and 1,2,4-trimethylbenzene from aromatics and formaldehyde, acetaldehyde, benzaldehyde and acetone from 

This study was to explore a bibliometric approach to quantitatively assessing current research trends on atmospheric aerosol, using the related literature in the Science Citation Index (SCI) database from 1991 to 2006. Articles were concentrated on the analysis by scientific output, research performances by individuals, institutes and countries, and trends by the frequency of keywords used. Over the years, there had been a notably growth trend in research outputs, along with more participation and collaboration of institutes and countries. Research collaborative papers shifted from national inter-institutional to international collaboration. The decreasing share of world total and independent articles by the seven major industrialized countries (G7) was examined. Aerosol research in environmental and chemical related fields other than in medical fields was the mainstream of current years. Finally, author keywords, words in title and keywords plus were analyzed contrastively, with research trends and recent hotspots provided.

Theoretical molecular descriptors were tested against log KOW values for polybrominated diphenyl ethers (PBDEs) using the Partial Least-Squares Regression method which can be used to analyze data with many variables and few observations. A quantitative structure–property relationship (QSPR) model was successfully developed with a high cross-validated value (Qcum2)">(Qcum2) of 0.961, indicating a good predictive ability and stability of the model. The predictive power of the QSPR model was further cross-validated. The values of log KOW for PBDEs are mainly governed by molecular surface area, energy of the lowest unoccupied molecular orbital and the net atomic charges on the oxygen atom. All these descriptors have been discussed to interpret the partitioning mechanism of PBDE chemicals. The bulk property of the molecules represented by molecular surface area is the leading factor, and KOW values increase with the increase of molecular surface area. Higher energy of the lowest unoccupied molecular orbital and higher net atomic charge on the oxygen atom of PBDEs result in smaller KOW. The energy of the lowest unoccupied molecular orbital and the net atomic charge on PBDEs oxygen also play important roles in affecting the partition of PBDEs between octanol and water by influencing the interactions between PBDEs and solvent molecules.

Source contributions to ambient PM10 (particles with an aerodynamic diameter of 10 μm or less) in Beijing, China were determined with positive matrix factorization (PMF) based on ambient PM10 composition data including concentrations of organic carbon (OC), elemental carbon (EC), ions and metal elements, which were simultaneously obtained at six sites through January, April, July and October in 2004. Results from PMF indicated that seven major sources of ambient PM10 were urban fugitive dust, crustal soil, coal combustion, secondary sulfate, secondary nitrate, biomass burning with municipal incineration, and vehicle emission, respectively. In paticular, urban fugitive dust and crustal soil as two types of dust sources with similar chemical characteristics were differentiated by PMF. Urban fugitive dust contributed the most, accounting for 34.4% of total PM10 mass on an annual basis, with relatively high contributions in all four months, and even covered 50% in April. It also showed higher contributions in southwestern and southeastern areas than in central urban areas. Coal combustion was found to be the primary contributor in January, showing higher contributions in urban areas than in suburban areas with seasonal variation peaking in winter, which accounted for 15.5% of the annual average PM10 concentration. Secondary sulfate and secondary nitrate combined as the largest contributor to PM10 in July and October, with strong seasonal variation peaking in summer, accounting for 38.8% and 31.5% of the total PM10 mass in July and October, respectively. Biomass burning with municipal incineration contributions were found in all four months and accounted for 9.8% of the annual average PM10 mass concentration, with obviously higher contribution in October than in other months. Incineration sources were probably located in southwestern Beijing. Contribution from vehicle emission accounted for 5.0% and exhibited no significant seasonal variation. In sum, PM10 source contributions in Beijing showed not only significant seasonal variations but also spatial differences.

Multiyear emission inventories of anthropogenic NMVOCs in China for 1980–2005 were established based on time-varying statistical data, literature surveyed and model calculated emission factors, which were further gridded at a high spatial resolution of 40 km×40 km using the GIS methodology. Results show a continuous growth trend of China's historical NMVOCs emissions during the period of 1980–2005, with the emission increasing by 4.2 times at an annual average rate of 10.6% from 3.91 Tg in 1980 to 16.49 Tg in 2005. Vehicles, biomass burning, industrial processes, fossil fuel combustion, solvent utilization, and storage and transport generated 5.50 Tg, 3.84 Tg, 2.76 Tg, 1.98 Tg, 1.87 Tg, and 0.55 Tg of NMVOCs, respectively, in 2005. Motorcycles, biofuel burning, heavy duty vans, synthetic fibre production, biomass open burning, and industrial and commercial consumption were primary emission sources. Besides, source contributions of NMVOCs emissions showed remarkable annual variation. However, emissions of these sources had been continuously increasing, which coincided well with China's economic growth. Spatial distribution of NMVOCs emissions illustrates that high emissions mainly concentrates in developed regions of northern, eastern and southern coastal areas, which produced more emissions than the relatively underdeveloped western and inland regions. Particularly, southeastern, northern, and central China covering 35.2% of China's territory, generated 59.4% of the total emissions, while the populous capital cities covering merely 4.5% of China's territory, accounted for 24.9% of the national emissions. Annual variation of regional emission intensity shows that emissions concentrating in urban areas tended to transfer to rural areas year by year. Moreover, eastern, southern, central, and northeastern China were typical areas of high emission intensity and had a tendency of expanding to the northwestern China, which revealed the transfer of emission-intensive plants to these areas, together with the increase of biomass open burning.

Multi-year inventories of vehicular emissions at a high spatial resolution of 40 km×40 km were established in China using the GIS methodology for the period 1980–2005, based on provincial statistical data from yearbooks regarding vehicles and roads, and on the emission factors for each vehicle category in each province calculated by COPERT III program. Results showed that the emissions of CH4, CO, CO2, NMVOC, NOx, PM10, and SO2increased from 5, 1066, 19 893, 169, 174, 26, and 16 thousand tons in 1980 to 377, 36 197, 674 629, 5911, 4539, 983, and 484 thousand tons in 2005 at an annual average rate of 19%, 15%, 15%, 15%, 14%, 16%, and 15%, respectively. Statistical analysis of vehicular emissions and GDP showed that they were well positively correlated, which revealed that increase of pollutant emissions has been accompanying the growth of GDP. Spatial distribution of pollutant emissions was rather unbalanced: over three-quarters of the total emissions concentrated in developed regions of China's southeastern, northern and central areas covering only 35.2% of China's territory, while the remaining emissions were distributed over the southwestern, northwestern and northeastern regions covering as much as 64.8% of the territory. In 2005, the Beijing–Tianjin–Hebei region, the Yangtze River Delta, and the Pearl River Delta covering only 2.3%, 2.2%, and 1.9%, respectively, of the territory, generated about 10%, 19%, and 12%, respectively, of the total emissions. Since 1990, motorcycles have been the major contributors to the CH4, CO, NMVOC, and PM10emissions, due to the large population. Heavy-duty vans were the major contributors to the NOx and SO2 emissions because of high emission factors. Passenger cars contributed about one third of the emissions of each pollutant. Contributions of vehicle categories to emissions varied from province to province, due to the diversity of vehicle compositions among provinces.

Based on measurements of fine particulate matter (PM2.5, i.e., particles with an aerodynamic diameter of 2.5 μm or less) in January and August 2004, serious air pollution persists in Beijing. The chemical analysis included organic and elemental carbon, water-soluble ions, and elemental compositions. The positive matrix factorization (PMF) method was used to apportion the PM2.5 sources. The sources contributing dominantly to PM2.5 mass concentrations are coal combustion in winter and the secondary products in summer. Furthermore, the contributions from motor vehicles, road dusts and biomass burning could not be neglected. The products of biomass burning for winter heating in the area around Beijing could enter the urban area during quasi-quiescent weather conditions. In conclusion, some effective control measures were proposed to reduce the PM2.5 pollution in Beijing.

Source apportionment of fine particulate matter (PM2.5, i.e., particles with an aerodynamic diameter of 2.5 μm or less) in Beijing, China, was determined using two eigenvector models, principal component analysis/absolute principal component scores (PCA/APCS) and UNMIX. The data used in this study were from the chemical analysis of 24-h samples, which were collected at 6-day intervals in January, April, July, and October 2000 in the Beijing metropolitan area. Both models identified five sources of PM2.5: secondary sulfate and secondary nitrate, a mixed source of coal combustion and biomass burning, industrial emission, motor vehicles exhaust, and road dust. On average, the PCA/APCS and UNMIX models resolved 73% and 85% of the PM2.5 mass concentrations, respectively. The results were comparable to previous estimate using the positive matrix factorization (PMF) and chemical mass balance (CMB) receptor models. Secondary products and the emissions from coal combustion and biomass burning dominated PM2.5. Such comparison among various receptor models, which contain different physical constraints, is important for better understanding PM2.5 sources.  

In this study, the hourly variations of the mass concentrations of PM10, SO2, NOx and O3 at three sampling sites were observed in Beijing during dust storm occurrence period in April 2000. The PM2.5 samples were simultaneously collected. By comparing the hourly variations of the pollutant concentrations before, during and after dust storm event and haze pollution episode, the variation characteristics of the mass concentrations of PM10, SO2, NOx and O3during dust storm events were presented. The results show that the mass concentration of PM10 reached 1500 μg m−3 during dust storm events on April 6 and 25, 2000, which was 5–10 times that of the non-dust weather conditions, and this period of high mass concentration of PM10 lasted for about 14 h, and then the concentration level prior to the dust event was recovered in 6-h time period. Due to the strong wind, the concentrations of SO2, NOx, NO2and O3 during dust storm period were maintained at low levels, which was significantly different from those on non-dust storm and haze pollution conditions. A lot of coarse particles as well as a very large amount of fine particles were contained in the atmospheric particulates during dust storm period, and the concentration level of PM2.5 was comparable to that during haze pollution episode. During the dust storm period, the PM2.5 concentration was approximately 230 μg m−3, accounting for 30% of the total PM10 mass concentration, was four times that of non-dust weather conditions, and the crustal elements constituted about 66.4% of the chemical composition of PM2.5 while sulfate and nitrate contributed much less, which was quite different from the chemical composition of PM2.5 primarily constituted by sulfate, nitrate and organics on haze pollution day.

Deterioration of cement concrete specimens caused by simulated acid rain was investigated by laboratory tests. Before and after cement concrete specimens were exposed to simulated acid rain, the neutralized depth, the compressive strength and the chemical compositions in the hardened cement paste were measured. The mineralogical composition of the concrete specimens was analyzed with XRD. The results lead to the following conclusions: the neutralized depth of the concrete specimens of all experiments can be described as a power function of exposure duration, CaO loss and the reduction rate of strength increased with H+and decreased with SO42− concentration in simulated acid rain. The original mineral compounds such as [Na K]AlSi3O8 and [Ca Na][SiAl]4O8 in the hardened cement paste are converted to CaSO4·2H2O, CaAl2Si2O8 and Ca3Al6O12·CaSO4. And these are larger in volume so that the reaction with SO42− ions result in volume expansion and strength decrease. The reduction rate of strength has a binary linear relation to the CaO loss rate and the ratio of SO3 content to CaO content in the hardened cement paste. So the deterioration of acid rain on the concrete specimen is caused by both H+ dissolution and SO42−expansion.