Measure And Study On The Atmospheric Pollutants In Three Typical Regional Background Stations Of China

To learn the concentration level and variation characteristics of key gaseous contaminants such as NOx and ozone and SO2in three typical regions around China, an observation was performed for those contaminants, from2009january to2010december, at three observational sites-DHS site in southern China, CBS site in northeastern China and FK site in northwestern China, which sites belong to Chinese Academy of Science. And by using meteorological observational data, we analysed the contaminants concentration level, diurnal and seasonal variation characteristics in those regions. We applied the multiple linear stepwise regression equation to the contaminants concentration simulate and assessed its performance by using observational data. In this study we try to reveal the Chinese regional background pollution status with the high speed development of economic and simulate the future pollution situation. The results of this study are:(1) Contaminants concentration level. Entire observational period the average concentration of NOx from vehicle emission at three typical observational sites-DHS site in southern China, CBS site in northeastern China and FK site in northwestern China are13.6,4.7and8.3ppbv, respectively. Average concentration of SO2which mainly from coal combustion are6.5,2.1and2.2ppbv, respectively. Ozone average concentration are18.6,33.0and29.1ppbv. Summer ozone maximum concentration at three sites are124.6、92.6and78.4ppbv. Background pollution situation is most serious in the Pearl River Delta region where economy is the most prosperous.(2) Seasonal variation. The NOx seasonal average concentration at DHS site of spring, summer, autumn and winter are (19±18.2),(10.5±10.3),(8.4±7.8),(15.8±15.5)ppbv, respectively. SO2are (7.8±8.4),(5.2±5.8),(4.9±6.9),(8.1±10.2)ppbv. Both of them are high in spring and winter, low in summer and autumn. NOx seasonal average concentration at CBS are (4.6±2.5),(4.1±1.9),(4.1±3.3) and (5.7±3.9)ppbv; SO2are (1.4±2),(0.83±0.6),(1.3±1.5),(4.6±4.0)ppbv, respectively. At FK site seasonal NOx concentration for four seasons are (5.5±4.6),(5.0±3.9),(11.9±12.7) and (14.2±12.7)ppbv; SO2are (1.8±2.2),(1.4±2.0),(1.3±2.2),(5.0±4.8)ppbv, respectively. Because of heating activities the NOx concentration in winter in CBS and FK sites are significant higher than other seasons. O3seasonal concentration at DHS site for each season are (15.6±19.9),(15.7±17.3),(25.5± 21.4),(16.6±16.4)ppbv, in CBS site are (43.6±17.8),(23.6±20.2),(23.2±13.8),(34.8±8.8)ppbv, in FK site are (37.9±14.2),(34.1±15),(16.1±11.2),(28±16.6)ppbv.(3) Statistical diurnal variation. Seasonal statistical diurnal variation for SO2and NOx at three sites represent as a single peak curve in all seasons, reached peak at08:00(LST). The maximum for daily average concentration occurred in winter at three sites.Which are75.0,18.7and64.3ppbv for DHS, CBS and FK site. The SO2maximum occurred in winter, which are34.0,13.6and15.8ppbv for three sites. The analysis results of ozone diurnal variation showed that ozone diurnal variation at three sites represent as a single peak curve, reached peak at14:00(LST). Ozone in DHS site have a more significant diurnal concentration range than in other sites. Ozone diurnal variation at FK siteis not so significant in winter, which is possibly relevant to advise meteorological factors for ozone production.High ozone concentration at CBS site in spring which is concordant with observation results at other background site.(4) Correlation with meteorological factors.Correlation analysis indicated at DHS NOx correlated positively with SO2, correlation coefficient is0.51. Wind velocity correlated negatively with NOx, SO2,positively with ozone ozone, correlation coefficients are-0.29,-0.15,0.12. NOx correlated positively with SO2at CBS, correlation coefficient is0.48. Relative humidity correlated significant negatively with ozone concentration at CBS site, correlation coefficient is-0.92. The linear of UV radiation and ozone is significant at DHS, CBS and FK, correlation coefficient is0.5,0.38and0.31.(5) Simulation and predict method. The performance of multiple linear stepwise regression equation for NOx and SO2at DHS site is good, simulate concentration and actual concentration mostly have the same trend. Correlation coefficients are0.84and0.77, respectively. R2are0.71and0.59respectively, and the relative average error are0.41and0.52. Correlation coefficient between ozone simulate and actual concentration in DHS is0.74, relative average error is0.56. Performance of equation for winter pollutants concentration at CBS site is pretty good, correlation coefficient for NOx, O3and SO2simulation and actual concentration is0.62,0.63and0.61, relative average error is0.08,0.05and0.06, R2is0.38,0.40and0.37respectively. Regression equation performance for summer ozone concentration at FK site is acceptable, correlation coefficient is0.87, relative average error is0.17. These results provide a practicable solution for regional background pollution research. The innovations in this dissertation are using the observation data from observation network of Chinese Academy of Science, assessed distribution and variation characteristics of NOx and SO2and ozone in three typical region in China for the first time. And assessed the influence of meteorological factors and the representiveness of sites.