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Yu X.,Nanjing University of Information Science and Technology | Ma J.,Nanjing University of Information Science and Technology | Ma J.,Guangzhou Hexin Analytical Instrument Company Ltd | An J.,Nanjing University of Information Science and Technology | And 6 more authors.
Journal of Cleaner Production | Year: 2016

With rapid industrialization and urbanization, air pollution and corresponding visibility problems in Nanjing were increasingly severe during the last few years. To better understand the potential causes of impaired visibility, particulate matter (PM) mass and chemical composition were measured from May 2013 to May 2014 in Nanjing. During the period, major water soluble ions and organic carbon exhibited obvious seasonal variations with the highest level in winter. On average, the water-soluble ions ranked in the order of SO42- > NO3 > NH4+ > Cl- > Na+ > Ca2+ > K+ > F- > Mg2+. The NO3 average ratios were over 1.0 in the fall and winter due to the low temperature favored a shift from the gas phase as nitric acid to the particle phase as ammonium nitrate. The averaged mass concentrations of organic carbon (OC) and elemental carbon (EC) were 18.96 and 2.60 μg m-3 respectively. The daily average visibility in Nanjing over study period ranged from 1.2 km to 18.4 km. High aerosol concentration and relative humidity were two important factors that cause low visibility events in Nanjing. The correlation between PM2.5 concentration and visibility under different relative humidity values showed that visibility was exponentially decreased with the increased PM2.5 concentrations when relative humidity less than 80%. However, the relationship was no longer to follow the exponentially decreasing trend when relative humidity >80%, and the visibility maintained in very low values, even with low PM2.5 concentrations. This indicated the hygroscopic growth of particles played more important roles for reduction of visibility. The annual average chemical extinction coefficient based on the revised IMPROVE (Interagency Monitoring of Protected Visual Environments) equation was 267.69 ± 139.24 Mm-1 in Nanjing. On average, organic matter was found to be the largest contributor accounting for 35.69% of chemical extinction coefficient. The contributions of ammonium sulfate and ammonium nitrate were also important with the annual average of 28.80% and 24.08%, respectively. For visibility >10 km, organic matter was the largest contributor to extinction coefficient, while organic matter and ammonium sulfate were the main contributors for visibility <5 km. The results showed that the most influential factors affecting visibility in Nanjing were organic matter and sulfate. The reduction of carbonaceous species and sulfate could effectively improve the visibility of Nanjing. The paper aims to help environmental scientists and policy makers understand air pollution in Nanjing and air pollution control strategies taken by government. © 2016 Elsevier Ltd.


Qin Y.,Nanjing University of Information Science and Technology | Yin Y.,Nanjing University of Information Science and Technology | Wu Z.,Weather modification office of Hebei Province | Shi L.,Weather modification office of Hebei Province
2010 2nd IITA International Conference on Geoscience and Remote Sensing, IITA-GRS 2010 | Year: 2010

Number concentration and size-distributions of aerosol particles were continuously measured at two locations in Shijiazhuang area (an urban site in Shijiazhuang and Zhaoxian, a suburb site), northern China, from May 11 to June 5, 2010, with an aerodynamic particle sizer spectrometer (APS). The spatial and temporal variations of aerosol properties were analyzed. The results show that fine-mode particles with diameters smaller than 1 μm dominate the number concentration at both sites, and the ratio of the concentration of particles in the size of 0.5-1μm account for 89.21% and 91.06%, respectively, of the total particles, which mainly came from polluted air emitted by industry and vehicle. However, the concentration of particles in the size of 2.5-20μm is higher in Shijiazhuang city than Zhaoxian. In addition, the diurnal variations of aerosol particles show multi peaks in Shijiazhuang, and a single peak in Zhaoxian. The variation of aerosol particle concentration may be related to the source and formation mechanism of fine particles. © 2010 IEEE.


Sun X.,Nanjing University of Information Science and Technology | Yin Y.,Nanjing University of Information Science and Technology | Han Y.,Nanjing University of Information Science and Technology | Xiao H.,Nanjing University of Information Science and Technology | And 2 more authors.
Zhongguo Huanjing Kexue/China Environmental Science | Year: 2012

Cloud droplets and cloud condensation nuclei (CCN) over Shijiazhuang area, Northern China, were measured based on airborne instruments during May to October, 2009. The data obtained from 7 flights were used to analyze the characteristics of number concentration, liquid water content, the mean diameter and the effective diameter of cloud droplets, as well as the spatial, temporal and spectral distribution of CCN in stratocumulus and altocumulus clouds under foggy/hazy weather conditions. The results show that the number concentration of cloud droplets was in the 10 2 orders of magnitude high under foggy/hazy weather conditions, and that the sizes of cloud particles measured at higher levels were larger than that at lower levels. The mean values of the cloud water content calculated from the droplet size spectra were between 0.03 to 0.14 g/m 3, and the mean value of CCN concentration averaged between the surface and at 600 m high was 3034 cm -3 (for supersaturation of 0.3%). The size distribution of CCN was fitted with a power law function and was shown of continental type. The results also show that clouds had a scavenging effect on CCN, but the CCN concentration could be increased remarkably due to present of an inverse layer.


Sun X.,Nanjing University of Information Science and Technology | Yin Y.,Nanjing University of Information Science and Technology | Sun Y.-W.,Weather Modification Office of Hebei Province | Duan Y.,Weather Modification Office of Hebei Province | Wu Z.-H.,Weather Modification Office of Hebei Province
Zhongguo Huanjing Kexue/China Environmental Science | Year: 2011

The vertical profile of number concentration and size distribution of aerosol particles at different altitudes over Shijiazhuang Area were analyzed based on aircraft measurements conducted in Hebei Province in 2006 and 2007. The size distributions were fitted with negative power function. The number concentration and size distribution of different heights were significantly different. The number concentration of aerosol particles in hazy days was one order of magnitude higher than that in the clean days, reaching 104/cm3. The mean diameter of particles ranged from 0.13 to 0.26 μm. Concentration of aerosol particles was very sensitive to weather conditions and the underlying surface. The size spectra of fine mode particles could be satisfactorily fitted with a negative power function.


Zhai Q.-F.,Nanjing University of Information Science and Technology | Jin L.-J.,Nanjing University of Information Science and Technology | Lin Z.-Y.,Nanjing University of Information Science and Technology | Wu Z.-H.,Weather Modification Office of Hebei Province | Kuang S.-S.,Shijiazhuang Meteorological Bureau
Zhongguo Huanjing Kexue/China Environmental Science | Year: 2011

During May, 2010, number concentration of atmospheric aerosols near the ground at Shijiazhuang Meteorological Bureau, China were measured using WPS made by MSP Corporation in United States, combined with corresponding meteorological data, to study the characteristics of aerosol number concentration and size distribution in this observation and possible causes that lead to. The spectra of aerosol were mainly occupied by ultrafine particles(DP<0.1 μm) in this observation. The average particle number concentration was high in all size scales. High emission of pollution gases and particles, weak wind condition and the transport effect when the dominant wind direction was southeast were the primary possible causes of this result. Obvious diurnal variation of aerosol concentration was observed in sunny days, which was mainly controlled by solar radiation, heat condition, the height of the boundary layer and construction, and that between different diameters had significant differences. Both total and ultrafine particles number concentration reached daily peak value at 7:00, 12:00 and 21:00, while coarse particles (DP>0.1 μm) number concentration reached the peak value at 7:00 and 23:00.


Sun Y.-W.,Weather Modification Office of Hebei Province | Sun Y.-W.,Key Laboratory of Meteorological and Ecological Environment of Hebei Province | Sun X.,Nanjing University of Information Science and Technology | Yin Y.,Nanjing University of Information Science and Technology | And 4 more authors.
Zhongguo Huanjing Kexue/China Environmental Science | Year: 2012

Aerosol measurements were conducted over Shijiazhuang area, Northern China, during the autumn of 2009, using the airborne Particle Measuring Systems (PCASP-100X, PMI Co. Ltd, USA) and forward scattering spectrum probe (FSSP-100-ER, PMI Co. Ltd, USA) of Weather Modification Office of Hebei Province. Measurements obtained in September and October in 2009 from seven flights in foggy days, one flight under rainy weather, and another flight under cloudy condition were chosen in this study to investigate the vertical and horizontal distributions of the concentration and mean diameter, as well as the size distribution of aerosol particles. Aerosol pollution over Shijiazhuang was quite heavy as compared to cleaner background regions, with the maximum particle concentration reaching 11910 cm -3 near the ground. It was also shown that the concentration of aerosol particles was mainly affected by weather conditions, and inversion layer was the main factor that controls the vertical distribution of aerosol particles. High concentration of aerosol particles was measured below an inversion layer, but it decreased rapidly above the inversion layer. Foggy days were usually associated with inversion layer and larger humidity, and was favorable of aerosol accumulation, therefore, maximum concentration of 10 4 cm -3 was measured under foggy weather, aerosol particles were accumulating with the days of non-precipitation before it reached the maximum and precipitation had a significant effect on aerosol removal. The results also indicated that the distributions of the concentration and size of aerosol particles were non-uniform in horizontal, and their absolute variations decreased with height and relative variations increase with height. Aerosol size distribution under the three weather conditions were similar with a single peak at about 0.11 μm, but the peak values of the aerosol number concentration decreased under the condition of foggy, Ci dens, and light rain conditions. With the increase in altitude, the peak values of the particle size distribution was becoming smaller, and the spectrum was also getting narrower.


Qin Y.,Weather Modification Office of Hebei Province | Liu S.,Hebei Meteorological Equipment Center | Duan Y.,Weather Modification Office of Hebei Province | Fan G.,Weather Modification Office of Hebei Province
AIP Conference Proceedings | Year: 2013

A case of using PMS to detect microphysics characteristics of stratus and aerosol in October, 2010 by the Weather Modification Office of Hebei Province is analyzed. The results show that Stratus is located in the altitude of 600-1100m in Shijiazhuang, and the cloud droplet number concentrations of the center position is 6.02×107m-3. In the vertical direction aerosol number concentration will decrease as the altitude rises. Atmospheric environmental the number concentration and average diameter of aerosol are the same trend, but the reverse is true for within clouds. With the altitude changes the drops spectrum distribution within status have differences. The drops spectrum concentrations in diameter of 0.1-1.0μm will decrease with rising altitudes. The droplet (>3.0μm) number concentrations are highest in the middle cloud, followed by top and bottom within clouds. The aerosol number concentrations at the bottom of the cloud are positively correlated with cloud droplet number concentrations. © 2013 AIP Publishing LLC.


Liu J.-Y.,Beijing University of Chemical Technology | Liu J.-Y.,CAS Institute of Atmospheric Physics | Liu Z.-R.,CAS Institute of Atmospheric Physics | Wen T.-X.,CAS Institute of Atmospheric Physics | And 8 more authors.
Huanjing Kexue/Environmental Science | Year: 2016

To characterize the size distribution of water soluble inorganic ions (WSII) in haze days, particle samples were collected by an Andersen cascade impactor in Shijiazhuang from October 15 to November 14 in 2013, and the concentrations of eight kinds of WSII (Na+, NH4 +, K+, Mg2+, Ca2+, Cl-, NO3 -and SO4 2-) during a typical haze episode were analyzed by ion chromatography. Sources and formation mechanism of WSII were analyzed based on their size distributions. The results showed that Shijiazhuang suffers serious air pollution during the autumn season. The daily average concentrations of PM10and PM2.5were (361.2±138.7) μg·m-3 and (175.6±87.2) μg·m-3 and the daily average concentration of PM2.5was 2.3 times as high as the national secondary standard. The total water soluble inorganic ion concentrations (TWSII) in clean days, light haze days and heavy haze days were(64.4±4.6)μg·m-3, (109.9±22.0)μg·m-3 and (212.9±50.1) μg·m-3 respectively. In addition, the ratio of secondary inorganic ions (SNA: SO4 2-, NO3 - and NH4 +) in TWSII increased from 44.9% to 77.6% as changed from clean days to the heavy haze days, suggesting the evolution of haze episodes mainly originated from the formation and accumulation of SNA. The size distributions of SO4 2-, NO3 - and NH4 + were bimodal in clean days, peaking at 0.43 -0.65 μm and 4.7-5.8 μm, respectively, which changed to unimodal distribution in both the light and heavy haze days, peaking at 0.65-1.1 μm. Owing to high humidity during the heavy haze days, the aqueous phase reactions of SO4 2- and NO3 - were likely promoted, which led to the transformation of condensation mode in clean days to the droplet mode in haze days. The size distributions of Na+, Mg2+ and Ca2+ were different with that of SNA, which showed a coarse mode peaking at 4.7-5.8 μm both in clean and haze days, whereas K+and Cl- showed a bimodal distribution both in clean and haze days, although the modal size was different in clean and haze days. © 2016, Science Press. All right reserved.


Duan Y.,Weather Modification Office of Hebei Province | Duan J.,Chinese Academy of Meteorological Sciences | Qin Y.,Weather Modification Office of Hebei Province
AIP Conference Proceedings | Year: 2013

In this research, based on the data of one time by the PCASP-100X probe of aircraft PMS and CCN counter detected under clear sky weather condition in summer over the Bohai-sea gulf area of north China at June 21, 2005, the distribution character of aerosols and CCN is primarily analyzed under different geography environment conditions over Bohai sea gulf area. The result shows that the aerosol concentration is 103 cm-3 in city boundary layer, upper troposphere is less than 103 cm-3, usually, and aerosol concentration value is decrease with height. Upper 600 meters level over the offing, the horizontal distribution of aerosol concentration value is relatively uniformity, it is generally 2000 to 6000 cm-3, which is less than one order of magnitude corresponding over the city and terrene height level, the result indicates that there is a significant different on distribution character of aerosols between the over city and Bohai-sea gulf area. At the same time, comparatively, the CCN counter detected result shows that CCN and aerosol concentration variety trend is similar with height over the city and sea area, which is exponential law. But, in atmospheric boundary, CCN and aerosol concentration value less than 1 to 5 times over offing area with over city area relatively. Otherwise, the researched result primarily suggests that weather conditions play an important rule for aerosol particle transportation in horizontal and vertical direction in atmospheric boundary layer. © 2013 AIP Publishing LLC.

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