Identification and quantification of shipping emissions in Bohai Rim, China

Rapid development of port and shipbuilding industry in China has badly affected the ambient air quality of coastal zone due to shipping emissions. A total of 60 ambient air samples were collected from background site of Tuoji Island in Bohai Sea strait. The air samples were analyzed for PM2.5, organic carbon (OC), element carbon (EC), inorganic elements, and water-soluble ions. The maximum concentration of PM2.5 was observed during spring (73.6 mu g.m(-3)) compared to winter (39.0 mu g.m(-3)) with mean of 54.6 mu g.m(-3). Back trajectory air mass analysis together with temporal distribution of vanadium (V) showed that V could be the typical tracer of shipping emissions at Tuoji Island. Furthermore, the ratios of vanadium to nickel (V/Ni), vanadium to lead (V/Pb) and vanadium to zinc (V/Zn) also suggest shipping emissions at Tuoji Island. The annual average primary PM2.5 estimate of shipping emissions was 0.65 mu g.m(-3) at Tuoji Island, accounting for 2.94% of the total primary PM2.5, with a maximum of 3.16% in summer and a minimum of 2.39% in autumn

Radiocarbon-based impact assessment of open biomass burning on regional carbonaceous aerosols in North China

Samples of total suspended particulates (TSPs) and fine particulate matter (PM2.5) were collected from 29th May to 1st July, 2013 at a regional background site in Bohai Rim, North China. Mass concentrations of particulate matter and carbonaceous species showed a total of 50% and 97% of the measured TSP and PM2.5 levels exceeded the first grade national standard of China, respectively. Daily concentrations of organic carbon (OC) and elemental carbon (EC) were detected 7.3 and 2.5 mu g m (3) in TSP and 5.2 and 2.0 mu g m (3) in PM2.5, which accounted 5.8% and 2.0% of TSP while 5.6% and 2.2% for PM2.5, respectively. The concentrations of OC, EC, TSP and PM2.5 were observed higher in the day time than those in the night time. The observations were associated with the emission variations from anthropogenic activities. Two merged samples representing from south and north source areas were selected for radiocarbon analysis. The radiocarbon measurements showed 74% of water-insoluble OC (WINSOC) and 59% of EC in PM2.5 derived from biomass burning and biogenic sources when the air masses were from south region, and 63% and 48% for the air masses from north, respectively. Combined with backward trajectories and daily burned area, open burning of agricultural wastes was found to be predominating, which was confirmed by the potential source contribution function (PSCF). (C) 2015 Elsevier B.V. All rights reserved

Measurements of emission factors of PM2.5, OC, EC, and BC for household stoves of coal combustion in China

As follow-up efforts for measurements on emission factors (EFs) of fine particulate matter (PM2.5) and its carbonaceous fractions for China's household coal stoves, a large-sized dilution sampling system was designed to test a total of 20 coal/stove combinations, which involve five coals with wide-ranged geological maturities and three stoves. Coal smoke was simultaneously collected onto quartz filter for organic carbon (OC) and elemental carbon (EC) analyses by thermal-optical reflectance (TOR) protocol and monitored online for optical black carbon (BC) by Aethalometer. The mean EFs based on burned fuel weight of PM2.5, OC, EC, and BC are 4.25 +/- 2.45, 1.11 +/- 0.72, 1.43 +/- 1.17, and 0.60 +/- 0.42 g/kg for bituminous coal, and 1.44 +/- 0.67, 0.05 +/- 0.02, 0.04 +/- 0.02, and 0.01 +/- 0.01 g/kg for anthracite, respectively. Significant differences are observed among the EFs for various coal/stove combinations, which are attributable to the differences of coal maturity, burning style and stove efficiency. Although the EFs of BC and EC are closely correlated (r = 0.97), the average BC/EC ratio is only 0.39, indicating a significant gap between the two methods; and the optical attenuation cross-section (sigma) for fresh coal smoke can be deduced as 6.47 m(2)/g, much lower than the manufacturer's preset value of 16.6 m(2)/g for Aethalometer. (C) 2015 Elsevier Ltd. All rights reserved.As follow-up efforts for measurements on emission factors (EFs) of fine particulate matter (PM2.5) and its carbonaceous fractions for China's household coal stoves, a large-sized dilution sampling system was designed to test a total of 20 coal/stove combinations, which involve five coals with wide-ranged geological maturities and three stoves. Coal smoke was simultaneously collected onto quartz filter for organic carbon (OC) and elemental carbon (EC) analyses by thermal-optical reflectance (TOR) protocol and monitored online for optical black carbon (BC) by Aethalometer. The mean EFs based on burned fuel weight of PM2.5, OC, EC, and BC are 4.25 +/- 2.45, 1.11 +/- 0.72, 1.43 +/- 1.17, and 0.60 +/- 0.42 g/kg for bituminous coal, and 1.44 +/- 0.67, 0.05 +/- 0.02, 0.04 +/- 0.02, and 0.01 +/- 0.01 g/kg for anthracite, respectively. Significant differences are observed among the EFs for various coal/stove combinations, which are attributable to the differences of coal maturity, burning style and stove efficiency. Although the EFs of BC and EC are closely correlated (r = 0.97), the average BC/EC ratio is only 0.39, indicating a significant gap between the two methods; and the optical attenuation cross-section (sigma) for fresh coal smoke can be deduced as 6.47 m(2)/g, much lower than the manufacturer's preset value of 16.6 m(2)/g for Aethalometer. (C) 2015 Elsevier Ltd. All rights reserved

Influence of monsoon system on alpha-HCH fate in Asia: A model study from 1948 to 2008

The Chinese Gridded Pesticide Emission and Residue Model was applied to simulate long-term environmental fate of -hexachlorocyclohexane (HCH) in Asia spanning 1948 to 2008. The simulation identifies the southern Tibetan Plateau and the margin of the Asian monsoon regime from the northeast area of the Tibetan Plateau to the Northeast China as sink areas. This spatial pattern of sink distribution is closely related to the summer monsoon activities in Asia. Wet deposition associated with the summer monsoon (June to August) is responsible for at least half of the -HCH mass entering into the sink areas. After deposition, relatively low temperature and high soil organic matter in the sink areas are favorable for -HCH detention. Chinese and Indian sources are the major contributors to -HCH contamination over the monsoon margin and the Tibetan Plateau, driven by the East Asian summer monsoon and South Asian summer monsoon, respectively

Emission factors for gaseous and particulate pollutants from offshore diesel engine vessels in China

Shipping emissions have significant influence on atmospheric environment as well as human health, especially in coastal areas and the harbour districts. However, the contribution of shipping emissions on the environment in China still need to be clarified especially based on measurement data, with the large number ownership of vessels and the rapid developments of ports, international trade and shipbuilding industry. Pollutants in the gaseous phase (carbon monoxide, sulfur dioxide, nitrogen oxides, total volatile organic compounds) and particle phase (particulate matter, organic carbon, elemental carbon, sulfates, nitrate, ammonia, metals) in the exhaust from three different diesel-engine-powered offshore vessels in China (350, 600 and 1600aEuro-kW) were measured in this study. Concentrations, fuel-based and power-based emission factors for various operating modes as well as the impact of engine speed on emissions were determined. Observed concentrations and emission factors for carbon monoxide, nitrogen oxides, total volatile organic compounds, and particulate matter were higher for the low-engine-power vessel (HH) than for the two higher-engine-power vessels (XYH and DFH); for instance, HH had NOx EF (emission factor) of 25.8aEuro-gaEuro-kWh(-1) compared to 7.14 and 6.97aEuro-gaEuro-kWh(-1) of DFH, and XYH, and PM EF of 2.09aEuro-gaEuro-kWh(-1) compared to 0.14 and 0.04aEuro-gaEuro-kWh(-1) of DFH, and XYH. Average emission factors for all pollutants except sulfur dioxide in the low-engine-power engineering vessel (HH) were significantly higher than that of the previous studies (such as 30.2aEuro-gaEuro-kg(-1) fuel of CO EF compared to 2.17 to 19.5aEuro-gaEuro-kg(-1) fuel in previous studies, 115aEuro-gaEuro-kg(-1) fuel of NOx EF compared to 22.3 to 87aEuro-gaEuro-kg(-1) fuel in previous studies and 9.40aEuro-gaEuro-kg(-1) fuel of PM EF compared to 1.2 to 7.6aEuro-gaEuro-kg(-1) fuel in previous studies), while for the two higher-engine-power vessels (DFH and XYH), most of the average emission factors for pollutants were comparable to the results of the previous studies, engine type was one of the most important influence factors for the differences. Emission factors for all three vessels were significantly different during different operating modes. Organic carbon and elemental carbon were the main components of particulate matter, while water-soluble ions and elements were present in trace amounts. The test inland ships and some test offshore vessels in China always had higher EFs for CO, NOx, and PM than previous studies. Besides, due to the significant influence of engine type on shipping emissions and that no accurate local EFs could be used in inventory calculation, much more measurement data for different vessels in China are still in urgent need. Best-fit engine speeds during actual operation should be based on both emission factors and economic costs

Application of PMF receptor model merging with PAHs signatures for source apportionment of black carbon in the continental shelf surface sediments of the Bohai and Yellow Seas, China

Black carbon (BC) and polycyclic aromatic hydrocarbons (PAHs) are byproducts generated from the incomplete combustion of organic materials, including fossil fuels and biomass. The similar production processes shared by BC and PAHs provide the possibility to infer the BC sources using the PAHs signatures. This study successfully utilized data sets of BC and PAHs analyzed from the continental shelf surface sediments of the Bohai and Yellow Seas to a standard receptor model of positive matrix factorization (PMF) to apportion the sources of BC in the sediment matrix. Results showed that combustion of fossil fuels (i.e., coal and oil/petroleum) accounted for an average level of 835% of the total BC preserved, which was significantly higher than that from the biomass burning (175%). The spatial distributions of the fossil BC concentrations and percentages differed significantly from those of the biomass BC, implying their different geochemical behaviors in the continental shelf regimes and further emphasizing the importance to effectively differentiate between fossil BC and biomass BC. In addition to the relative proportions of the BC subtypes (char-BC/soot-BC), the regional-specific hydrodynamic conditions, including the cold cyclonic eddy, resuspension and coastal current, also exerted a significant influence on these spatial variations

Flux and budget of BC in the continental shelf seas adjacent to Chinese high BC emission source regions

This study conducted the first comprehensive investigation of sedimentary black carbon (BC) concentration, flux, and budget in the continental shelves of Bohai Sea (BS) and Yellow Sea (YS), based on measurements of BC in 191 surface sediments, 36 riverine water, and 2 seawater samples, as well as the reported data set of the atmospheric samples from seven coastal cities in the Bohai Rim. BC concentrations in these matrices were measured using the method of thermal/optical reflectance. The spatial distribution of the BC concentration in surface sediments was largely influenced by the regional hydrodynamic conditions, with high values mainly occurring in the central mud areas where fine-grained particles (median diameters>6 (i.e., <0.0156mm)) were deposited. The BC burial flux in the BS and YS ranged from 4 to 1100 mu g/cm(2)yr, and averaged 166200 mu g/cm(2)yr, which was within the range of burial fluxes reported in other continental shelf regimes. The area-integrated sedimentary BC sink flux in the entire BS and YS was 325Gg/yr, and the BS alone contributed 50% (157Gg/yr). The BC budget calculated in the BS showed that atmospheric deposition, riverine discharge, and import from the Northern Yellow Sea (NYS) each contributed 51%, 47%, and 2%. Therefore, atmospheric deposition and riverine discharge dominated the total BC influx (98%). Sequestration to bottom sediments was the major BC output pattern, accounting for 88% of the input BC. Water exchange between the BS and the NYS was also an important BC transport route, with net BC transport from the BS to the NYS