Representativeness of Urban Highest Polluted Zones for Sitting Traffic-Oriented Air Monitoring Stations in a Chinese City(<Special Issue>Urban Air and Environment Control Technologies)

Passive sampling technique was used to preliminary assess the spatial and temporal distribution of air pollution in Suzhou (P. R. China) in 2003, with the aim to determine the representativeness of zones where to monitor air quality. 100 sites were selected to measure 15-days average concentrations of SO_2, NO_x, NO_2, O_3, NH_3, Benzene, Toluene and Xylene in winter and summer. The distribution trend of NO and NO_2, as well as the ratio of NO_2/NO_x was used to identify the heavy traffic polluted zones and design a network of monitoring stations (macrositing). NO_2/NO_x ratios varied throughout the two selected seasons and from site to site clearly demonstrating the different extent and completeness of NO→NO_2 oxidation processes in time and space. The exceedance frequencies of pollutants was used to design the type of monitoring equipment to be installed at each station (micrositing). An air quality monitoring network composed by 9 monitoring stations has been finally established in 2004 according to the result of this survey and is now currently running.