Characteristics of gaseous pollutants at Jinsha, a remote mountain site in Central China

Abstract

Ground O3,SO2,NOx,CO and meteorological data were obtained from June 2006 to July 2007 at Jinsha regional atmospheric background station in Central China.The concentration levels and variations of O3,SO2,NOx and CO were analyzed and their influencing factors were discussed.The results showed that during the observation period,the average concentrations of O3,SO2,NOx and CO were 24.6 ± 17.0 ppb,2.8 ± 5.5 ppb,5.6 ± 5.5 ppb and 502 ± 222 ppb,respectively,which were lower than those observed at a similar latitude site,Linan regional atmospheric background station in the Yangtze River Delta region.At Jinsha station,local photochemical production of O3 is not significant and the average daily change of pollutants is relatively stable,which are different from those observed at Lin'an and Shangdianzi(North China) Regional atmospheric background station.Because of its relative isolation and relatively high altitude,some feature of free atmosphere can be able to be captured at Jinsha station.The feature can be characterized as that O3 concentration maintained high concentrations for days,while the other pollutants of NOx,SO2 and CO kept a very low concentration;during the event,relative humidity significantly decreased to a lower level and showed an apparent anti-correlation with O3 variation.Therefore,it can be able to reflect the changes of the background signals in a larger scale.