Abstract: In order to track the influences of the natural draft cooling tower (NDCT) with flue gas injection on the regional atmospheric environment and pollutant concentrations in the theoretical plume-downwash area, SO₂ and NO₂ in the area of 400 km² around the Qinling power plant are sampled and analyzed during the heating and non-heating periods, an automatic air quality monitoring station is set to get hourly observations in the theoretical plume downwash area of the NDCT over a year, and combined with meteorological data, an empirical study on the environmental impact of NDCT with flue gas injection is carried out. The results show that the monitoring results of the ambient air quality in both heating period and non-heating period meet the requirements of "the ambient air quality standard" (GB 3095—2012), and the influence of the power plant on the regional environment is acceptable. During the continuous monitoring of the ambient air over time, high concentration of local pollutants resulting from flue gas downwash is not observed. There is no significant difference (P>0.05) between the pollutant concentration in the theoretical washing area when the dominant wind is westward or eastward. The pollutant concentration in the strong wind is significantly lower than that in the low wind (P<0.01) when the wind is westward. The monitoring results show that high concentration of ground pollutants will not happen in the theoretical plume-downwash area of NDCT with flue gas injection.

Key words: coal-fired generation power, natural draft cooling tower with flue gas injection, automatic air quality monitoring station, plume downwash, regional environmental quality, statistical test