Abstract: In this paper,the atmospheric SO₂,O₃ and NO₂ of Hefei High-tech Zone are continuously observed using long-path differential absorption spectroscopy system,and the characteristics of gas pollution and possible pollution sources are analyzed.The diurnal variation shows that SO₂ is high at night and low during the day.The diurnal variation of NO₂ shows a single peak and single valley type.The rush hour of off-duty traffic has certain effect on NO2.But the whole day concentration of NO₂ is on the high side (35~45 μg/m) and the variation is small,so there exist  other important nitrogen oxide emission sources.The diurnal variation of O₃ is obvious.Its daytime concentration is high,and the maximum value appears at 16:00 in the afternoon;the concentration is low at night,and the lowest value appears on the early morning.The concentration of NO₂ and SO₂ in winter is high because of low atmospheric boundary layer.In summer,photolysis reaction is intense,wet deposition is obvious,so the concentration of pollutants is low.On the contrary,the seasonal variation of O₃ is contrary.The analysis of pollution sources shows that the high SO2 value is mainly related to the coal burning of rural residents in the northwest of the observation site and the unorganized emission of pharmaceutical companies and paint factories in the southeast of the observation site.However,the high value of NO₂ in the east-northeast (wind speed > 6 m/s) wind direction is affected by the long-distance transmission from Hefei Wanneng Power Plant and vehicle exhaust emissions in busy urban areas.The wind speed and direction distribution of O₃ and NO₂are basically opposite.The correlation coefficient of NO2 and O₃ is only -0.429 6.There are other important O3 precursor pollutants in the atmosphere of Hefei Hi-tech Zone.

Key words: SO2, O3, NO2, pollution, characteristics, sources