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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.


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.


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.


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 | 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.

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