Jiangsu Key Laboratory of Atmospheric Environmental Monitoring and Pollution Control
Jiangsu Key Laboratory of Atmospheric Environmental Monitoring and Pollution Control
Hu B.,Nanjing University of Information Science and Technology |
Hu B.,Jiangsu Key Laboratory of Atmospheric Environmental Monitoring and Pollution Control |
Tang L.,Nanjing University of Information Science and Technology |
Tang L.,Jiangsu Environmental Monitoring Center |
And 11 more authors.
Huanjing Kexue Xuebao/Acta Scientiae Circumstantiae | Year: 2017
Real-time compositional measurements of atmospheric submicron aerosol particle (NR-PM1) were conducted in urban Nanjing during heavy pollution episodes in December and August 2013 using an Aerodyne Aerosol Chemical Speciation Monitor. NR-PM1 compositions were organics (51.8% and 44%), nitrate (12.8% and 23%), sulfate (20.9% and 13%), ammonium (14% and 16.8%), and chloride (0.5% and 3.2%) in December and August, respectively. The secondary inorganic aerosols, e.g., sulfate and nitrate, showed quite different diurnal variations in December and August. For example, nitrate presented a gradual increase during daytime in December, suggesting that daytime photochemistry played a more important role in nitrate formation. The high concentration of sulfate was mainly observed under highly relative humidity (RH) conditions during nighttime in December, but it showed a significant noon peak during daytime in August. This means that the sulfate formation might be driven by RH-dependent pathway in December and gas-phase photochemical processing in August, respectively. During ozone pollution episodes in August, oxygenated OA (OOA) showed a significant enhancement along with sulfate during daytime, indicating regional influence on secondary aerosol formation. Both secondary inorganic and OOA presented a significant enhancement during heavy pollution episodes in December, highlighting the importance of regional secondary aerosols in the formation of severe pollution episodes in Nanjing. © 2017, Science Press. All right reserved.
Sun J.,Nanjing University of Information Science and Technology |
Zheng Y.F.,Nanjing University of Information Science and Technology |
Zheng Y.F.,Jiangsu Key Laboratory of Atmospheric Environmental Monitoring and Pollution Control |
Wu R.J.,Nanjing University of Information Science and Technology |
And 2 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2014
At present, the aerosol radiative effect is the focus of many scholars and the solar radiation attenuated by direct or indirect effect to cause crop photosynthetic capacity decreased, resulting in crop production; At the same time the surface concentration of O3continuously increased, O3has strong negative effect on crop growth and metabolic processes and O3was direct threat to food safety to crops. Providing the basis for the security of National grain assessments and production under the conditions of reduced solar irradiance and elevated ozone concentration and other changes in atmospheric. Used open-top chamber (OTC) and black shading network to launch a fumigation level and two kinds of irradiance reduction degree. (field: CK, T1: shading 20%, T2: shading 40%, T3: 100nL/ L O3concentration, T4: 100nL/ L O3concentration and shading 20% compound, T5: 100nL / L O3concentration and shading 40% compound). The results showed that contrasting to CK, the Fv / Fm(PS II maximum quantum yield), L(PFD)(the relative limit of Photosynthetic function) of T1 treatment are similar and had no obvious changes, but the Yield, qP (Photochemical quenching coefficient), Y (NO) (the non regulation of energy dissipation in quantum yield), (1-qP) / NPQ(Light quantum excess degree) are decreased by 1.3%- 21.5%, 7. 5%-21. 2%, 14. 8%-20. 6%, 27. 7%-51. 4% and NPQ(non photochemical quenching coefficient), Y (NPQ)(regulation of energy dissipation in quantum yield) are increased by 12.0%-31.9%, 53.4%-116%. Fv/ Fm of T2 treatment had no significant changes, The Yield, qP, L(PFD), Y(NO), (1-qP) / NPQ were decreased by 13.2%- 34.0%, 16.9%-36.2%, 6.8%-8.3%, 2.8%-16.0%, 23.1%-32.7%, The NPQ, Y(NPQ) were increased downby 15.9%-38.2% 39. 5%-65. 4%. The Fv / Fm, Yield (Optical system II actual photochemical efficiency), qP of T3 treatment were decreased by 11.8%-12.6%, 19.1%-28.0%, 15.6%-43.1%. The L(PFD), NPQ, Y (NPQ), Y (NO), (1-qP) / NPQ increased by 1.1%-7.2%, 20.8%-83.6%, 12.6%-40.3%, 3.9%-22.2% obviously, 0.6%-34.1%. Fv / Fm, L(PFD)of T4 treatment were similar to CK and compared with CK, the Yield, qP, Y (NO), (1-qP) / NPQ decreased by 12.7%-42.8%, 7.2%-14.4% 18. 8%-27. 5%, 16. 4%-45. 1% and NPQ, Y (NPQ) increased by 13.4%-45.2% 6.9%-110.8%. Fv / Fm, Yield, qP, L(PFD), Y(NO), (1-qP) / NPQ of T5 treatment compared with CK, decreased by 30.4%-50.9%, 27.7%-43.2%, 2.2%-4.9%, 2.2%-10.2%, 23.3%-26.2%, 47.1%-61.6% and NPQ, Y(NPQ) increased by 27.5%-51.6% 63.3%-142.7%. Those results showed that (1) the single factor of Ozone significantly changed photosynthetic activity and distribution of light energy of winter wheat leaves but the single factor of reduced solar radiation alleviated negative effect photosynthesis restriction of winter wheat to a certain extent. (2) Further, under the combined stress, the light energy of winter wheat distributed more to regulatory heat dissipation. Composite action enhanced obviously the heat dissipation capability of winter wheat Radiation attenuation effect could cause winter wheat at the ozone stress self-regulated to better adapt to the adverse environment. Reducing appropriate the amount of solar radiation under Ozone stress could alleviate and reduce the light injury of winter wheat leaves. (3) Reducing solar radiation under the Ozone stress could inhibition the light injury and ensure the winter wheat optical system function normally and the normal growth of Winter Wheat. (4) In spite of winter wheat on composite stress has a certain ability to adapt; the reduced solar irradiance and elevated ozone concentration are still an important issue facing national grain production.
Yang X.-X.,Nanjing University of Information Science and Technology |
Yang X.-X.,Jiangsu Key Laboratory of Atmospheric Environmental Monitoring and Pollution Control |
Tang L.-L.,Nanjing University of Information Science and Technology |
Tang L.-L.,Jiangsu Key Laboratory of Atmospheric Environmental Monitoring and Pollution Control |
And 13 more authors.
Huanjing Kexue/Environmental Science | Year: 2016
Volatile organic compounds (VOCs) is an important precursor of photochemical ozone pollution (O3) in the atmosphere. Their concentration variation directly affects the characteristics of the ozone pollution. The concentration, speciation of VOCs, ozone and its precursors in Nanjing were analyzed and measured using online gas detection systems in August 2013. VOCs/NOx discriminant method was used to get the sensitive control factors of ozone. The results showed that the averaged volume fraction of VOCs was 52.05×10-9, and the largest one reached 200×10-9 in Nanjing urban district. The order of volume fraction of each species VOCs was alkane>oxygen-containing VOCs>alkene>aromatics. The averaged concentration of ozone was 76.5 μg·m-3 and the exceeding concentration of hourly standard was 5.9%. The change trends of ozone precursors VOCs and NOx were basically identical and Ozone showed the obvious negative correlation during the period of high concentrations of ozone. There were some differences in the concentrations of the same VOCs in different ozone concentration periods. The ozone generation in Nanjing urban district was sensitive to VOCs, and Nanjing belonged to VOCs control area in summer. © 2016, Science Press. All right reserved.
Wang L.,Jiangsu Key Laboratory of Atmospheric Environmental Monitoring and Pollution Control |
Bian C.,Jiangsu Key Laboratory of Atmospheric Environmental Monitoring and Pollution Control |
Li Q.,Jiangsu Key Laboratory of Atmospheric Environmental Monitoring and Pollution Control |
Jiang D.,Jiangsu Key Laboratory of Atmospheric Environmental Monitoring and Pollution Control |
Kong J.,Jiangsu Key Laboratory of Atmospheric Environmental Monitoring and Pollution Control
Journal of Natural Disasters | Year: 2014
This paper used standardized precipitation index (SPI) and Morlet wavelet analysis method to analyze the temporal, periodic and spatial variation characteristics of drought in Shaanxi Province by the daily precipitation data from 1961 to 2010. Effect of drought on crop yield per unit area in 17 counties (districts) of Shaanxi Province was studied by the corn production data from 2007 to 2010 and the panel date model. The results showed that, the trend of drought is on the increase. The most serious case occurred in 1990s. Damage degrees of drought in Shaanxi Province decreased continuously from north to south. The most serious condition occurred in northern Shaanxi, followed by Guanzhong. Southern Shaanxi is the lightest. Time series of drought years exhibits two significant periods. One is 2 - 4 years and the other is 4 years. In addition, it is found that corn production is in negative correlation with the drought. One grade of increase of drought index (the standardized precipitation index) will lead to 128.985kg/hm2 reduction in corn production. It is hoped that the study may help to make relative disaster mitigation policies and to guarantee the stability of corn production in Shaanxi region.