In order to tackle China's severe air pollution issue, the government has released the "Air Pollution Prevention and Control Action Plan" (known simply as the "Action Plan") since 2013. A recent study reported a decreased trend in PM concentrations over 2013-2017, but O pollution has become more serious. However, the effects of surface O on crops are unclear after the implementation of the "Action Plan".
View Article and Find Full Text PDFAn eddy-covariance system combined with a semi-mechanistic model was used to analyze variations in gross primary productivity (GPP) and to simulate the impact of ozone (O) on GPP under different levels O concentrations over a winter wheat field in Nanjing. The results showed that GPP was higher during the middle of the growth period and low during the early and late growth periods, reaching a maximum of 40 μmol·(m·s). Using high and low ozone sensitivity settings,O-damage in 150, 100, 50 nL·L and control treatment (CK) reduced GPP by -72%, -36%, -6%, and -10%, and by -13%, -6%, -1%, and -2%, respectively.
View Article and Find Full Text PDFTo better understand the ozone deposition and risk assessment over agroecosystems based on the ozone flux indices, an eddy-covariance system was used for measuring the ozone deposition continuously and dynamically in a winter wheat field. We analyzed the variations in ozone concentration, total ozone flux, and stomatal and non-stomatal flux. The relationships between stomatal/non-stomatal ozone deposition velocity and the main meteorological factors were investigated.
View Article and Find Full Text PDFSurface ozone pollution and its negative effects on crops and food safety have attracted the attention of many people. In this study, ozone concentration and meteorological parameters in a winter wheat field were measured from 2014 to 2016. We analyzed the variations in ozone concentration and AOT40 during the growing season for winter wheat.
View Article and Find Full Text PDFIn recent years, surface ozone concentration has been increasing. A high concentration of ozone can affect the growth of crops, and reduce crop yields. In this paper, based on hourly ozone concentration data in the Nanjing area obtained from 2014 to 2016, we analyzed the variation characteristic of ozone concentration and its effect on the production and economic loss of winter wheat and rice.
View Article and Find Full Text PDFInt J Environ Res Public Health
March 2018
Ground-level ozone pollution in Beijing has been causing concern among the public due to the risks posed to human health. This study analyzed the temporal and spatial distribution of, and investigated population exposure to, ground-level ozone. We analyzed hourly ground-level ozone data from 35 ambient air quality monitoring sites, including urban, suburban, background, and traffic monitoring sites, during the summer in Beijing from 2014 to 2017.
View Article and Find Full Text PDFAs one of the main atmospheric pollutants over surface layer,researches on the increasing surface ozone concentration and its impact on main crops have become the focus of every government and the public.In this paper,based on the observations in Nanjing using the main local cultivars in China's major winter wheat producing areas,it was expected to obtain the data including ozone concentration,meteorological data and stomatal conductance by continuous observation.Stomatal conductance model was used and parameterized,combined with flux model,we analyzed the characteristics of stomatal flux in winter wheat under ozone pollution.
View Article and Find Full Text PDFSurface-level ozone pollution causes crop production loss by directly reducing healthy green leaf area available for carbon fixation. Ozone and its precursors also affect crop photosynthesis indirectly by decreasing solar irradiance. Pollutants are reported to have become even more severe in Eastern China over the last ten years.
View Article and Find Full Text PDFHuan Jing Ke Xue
January 2014
Employing floating static chamber-chromatography method, the N2O diurnal fluxes at the water-air interface of four rivers (Tuanjie River, Jinchuan River, Inner and Outer Qinhuai River) and Jinniu Lake were monitored in Nanjing during summer. The results show that four rivers act as the sources of N2O emission, but Jinniu Lake is characterized by the absorption of N2O. The highest N2O flux from Inner Qinhuai presented at 20:00 because of the changing of hydrodynamic conditions.
View Article and Find Full Text PDFYing Yong Sheng Tai Xue Bao
September 2013
From the viewpoint of land surface evapotranspiration, and by using the semi-empirical evapotranspiration model based on the Priestley-Taylor equation and the land surface temperature-vegetation index (LST-VI) triangle algorithm, the current monitoring technology of agricultural drought based on remote sensing was improved, and a simplified Evapotranspiration Stress Index (SESI) was derived. With the application of the MODIS land products from March to November in 2008 and 2009, the triangle algorithm modeling with three different schemes was constructed to calculate the SESI to monitor the agricultural drought in the plain areas of Beijing, Tianjin, and Hebei, in comparison with the Temperature Vegetation Dryness Index (TVDI). The results showed that SESI could effectively simplify the remote sensing drought monitoring method, and there was a good agreement between SESI and surface soil (10 and 20 cm depth) moisture content.
View Article and Find Full Text PDFExperiments were conducted under open-top-chambers conditions to assess the photosynthetic responses of wheat plants (Triticum aestivum L., YangMail6) to supplemental UV-B radiation (10%-10.9% higher then control group, T1) and enhanced ozone [(100 +/- 9) nmol x mol(-1), T2], separately and in combination (combination treatment, T3), making use of LCpro + Portable Photosynthesis System and DIVING-PAM Fluorometer to determine gas exchange and chlorophyll fluorescence parameters.
View Article and Find Full Text PDFInt J Biometeorol
September 2012
A variety of research has linked high temperature to outdoor thermal comfort in summer, but it remains unclear how outdoor meteorological environments influence people's thermal sensation in subtropical monsoon climate areas, especially in China. In order to explain the process, and to better understand the related influential factors, we conducted an extensive survey of thermally comfortable conditions in open outdoor spaces. The goal of this study was to gain an insight into the subjects' perspectives on weather variables and comfort levels, and determine the factors responsible for the varying human thermal comfort response in summer.
View Article and Find Full Text PDFYing Yong Sheng Tai Xue Bao
June 2011
Taking winter wheat Triticum aestivum L. (cv. Yangmai 13) as test material, a field experiment was conducted in Nanjing City to study the effects of simulated reduced solar radiation on the diurnal variation of winter wheat flag leaf photosynthetic rate and the main affecting factors.
View Article and Find Full Text PDFHuan Jing Ke Xue
February 2011
A continuing 26-hour monitoring is given on the physical and chemical indicators of the water around the Potamogeton crispus population in Xuanwu Lake, Nanjing City to study the consequent environmental effects. The result shows that both the highest (11.85 mg/L) and the lowest (9.
View Article and Find Full Text PDFStress effects of surface increased ozone concentration on winter wheat photosynthesis, lipid peroxidation and antioxidant systems in varied growth stages (jointing stage, booting stage, blooming stage and grain filling stage) were studied, the winter wheat was exposed to open top chambers (OTCs) in an open field conditions to three levels ozone concentrations (CK, 100 nmol x mol(-1), 150 nmol x mol(-1)). The results revealed that within 150 nmol x mol(-1) ozone concentration, as the ozone concentration and time increased,total chlorophyll content,chlorophyll a and b contents of winter wheat leaves were general declined,but compared to CK, the total chlorophyll and chlorophyll a content of T1 treatment groups were a little higher at booting and blooming stage; the conductance of stomatal was affected, the activation of unit leaf area decreased, intercellular CO2 concentration and stomatal limitation value showed a fluctuation change tendency. At the same time, a self-protective mechanism of winter wheat were launched.
View Article and Find Full Text PDFIn order to provide basis for evaluating the effects of air pollutant such as O3 on crops yield and food security, the effects of O3 fumigation (ambient air, CK; 100 nL x L(-1), T1; 150 nL x L(-1), T2) on chlorophyll a fluorescence and gas exchange of a field-grown winter-wheat (Triticum aestivum L. Yang Mai 13) in different growing period were conducted via open-top chamber technique in conjunction with Diving-PAM fluorometer and LC pro + photosynthesis system. Results indicated that Fv/Fm caused by T1 was higher than 0.
View Article and Find Full Text PDFInt J Biometeorol
January 2010
With global warming forecast to continue into the foreseeable future, heat waves are very likely to increase in both frequency and intensity. In urban regions, these future heat waves will be exacerbated by the urban heat island effect, and will have the potential to negatively influence the health and welfare of urban residents. In order to investigate the health effects of the urban heat island (UHI) in Shanghai, China, 30 years of meteorological records (1975-2004) were examined for 11 first- and second-order weather stations in and around Shanghai.
View Article and Find Full Text PDFYing Yong Sheng Tai Xue Bao
October 2008
With winter wheat variety Yamgmai 12 as test object, a field experiment was conducted to study the stress of simulated acid rain on its growth and development. The results showed that simulated acid rain had considerable effect on wheat growth and yield. When the pH of acid rain was < or = 3.
View Article and Find Full Text PDFThe hollow Co(3)O(4) microspheres (HCMs) were prepared by the carbonaceous templates, which did not need the surface pretreatment. The chemiluminescence (CL) and catalytic properties for CO oxidation over these hollow samples were evaluated. The samples were characterized by scanning electron microscopy (SEM), energy disperse spectra (EDS), transmission electron microscopy (TEM), selected area electron diffraction (ED), X-ray diffraction (XRD), temperature-programmed desorption (TPD) and N(2) adsorption.
View Article and Find Full Text PDFBased on the effects of various additives on ultrasonic degradation of 2,4-dinitrophenol (DNP) in aqueous solution, the degradation mechanisms and reaction kinetics of DNP in different processes were proposed. The results showed that some additives, such as CuO, CCl(4), O(3), NaCl and KI, were favorable for DNP sonochemical degradation. On the contrary, DNP degradation efficiency was restrained by Na(2)CO(3), indicating that OH radicals oxidation played an important role in DNP ultrasonic removal.
View Article and Find Full Text PDFThe Agricultural Production Systems Simulator (APSIM) was applied to simulate the 1999-2001 field experimental data and the 2002-2003 water use data at the Yucheng Experiment Station under Chinese Ecosystem Research Network, aimed to verify the applicability of the model to the wheat-summer maize continuous cropping system in North China Plain. The results showed that the average errors of the simulations of leaf area index (LAI), biomass, and soil moisture content in 1999-2000 and 2000-2001 field experiments were 27.61%, 24.
View Article and Find Full Text PDFCoal water slurry (CWS) was prepared with a newly developed additive from naphthalene oil. The effects of ultrasonic irradiation on coal particle size distribution (PSD), adsorption behavior of additive in coal particles and the characteristics of CWS were investigated. Results showed that ultrasonic irradiation led to a higher proportion of fine coal in CWS and increased the saturated adsorption amount of additive in coal particles.
View Article and Find Full Text PDFA variety of research has linked extreme heat to heightened levels of daily mortality and, not surprisingly, heat waves both in 1998 and in 2003 all led to elevated mortality in Shanghai, China. While the heat waves in the two years were similar in meteorological character, elevated mortality was much more pronounced during the 1998 event, but it remains unclear why the human response was so varied. In order to explain the differences in human mortality between the two years' heat waves, and to better understand how heat impacts human health, we examine a wide range of meteorological, pollution, and social variables in Shanghai during the summers (15 June to 15 September) of 1998 and 2003.
View Article and Find Full Text PDFUltrason Sonochem
September 2006
Ultrasonic degradation of halomethane mixtures, with very low initial concentration in chlorinated drinking water was investigated. It was observed that the removal efficiencies of four halomethanes after 1 h ultrasonic irradiation followed the increasing order: CHCl(3) < CHBr(2)Cl < CHBrCl(2) < CCl(4) and the degradation reactions of the halomethanes were well described by the pseudo-first-order kinetics model. Molecular polarity was found to be an important factor controlling the sonodegradation of halomethane mixtures.
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