Characteristics Of Surface Ozone Concentrations And Its Influence Factors In Nanjing Northern Suburb

O3 plays a key role in the global and regional atmospheric environmental changes, it is not only the important influence of atmospheric radiation systems, environmental effect and the city atmosphere plays.This paper is based on the field data of Nanjing, the interaction of atmospheric ozone and its precursors and meteorological factors were studied; depth analysis of the interaction of polluted gases such as O3, on the influence of meteorological factors on concentration of pollutants were discussed. The main research contents are as follows:The results showed that the averaged mixing ratios of ozone (03)、nitrogen oxide (NO;,) and volatile organic compounds (VOCs) in Nanjing northern suburb were about (32.01±15.20), (21.50±14.02) and (33.16±25.20)x10-9, respectively, and Carbon monoxide (CO) (0.66±0.44)×10-6. For O3, the maximum value reached 146.42×10-9, exceeding the National Ambient Air Quality Standard Ⅱ by a rate of 14.1%. There were 11 days with occurrence of haze, accounting for the entire observation period by a rate of 11.1%. A relatively higher probability of hourly O3 averages over 80 ppbv in Nanjing indicates more severe ozone pollution. A close similarity could be found in O3 probability distributions at both sites, implying a good regional mixing over the polluted Nanjing. Pollutants were significantly affected by local emission sources near the site. When affected by the southwest wind with the speed of 2-3m/s, active species of VOCs were easy to reach high level, accompanied by an increase concentration of O3; Under the influence of easterly winds, NOx, CO and VOCs, mainly emitted from industrial sources and traffic sources, were prone to reach high level. The observation site was located in the downwind area of the urban district so it was easily affected by the power plant plume and the ozone generation efficiency (OPE) was about 2.17±0.12. Ozone precursor relationships are crucial to understanding of the local ozone processes. Determining whether an area is NOx-limited or VOCs-limited is an important step in the development of effective ozone control strategies. Model simulations were conducted to investigate the contributions of different O3 precursors to the formation of O3 formation. Alkenes were found to be the largest contributors to O3 production (RIR=1.16±0.17). Aromatics were second (RIR=0.33±0.07). Generally the production of 03 in Nanjing area is limited by volatile organic compounds (VOCs), while high nitric oxide (NO) concentrations suppress O3concentration.