Investigating the impacts of coal-fired power plants on ambient PM2.5 by a combination of chemical transport model and receptor model

Aiming at evaluating the impact of coal-fired power plants on urban air quality and human health, a one-month intensive observation campaign was conducted in a typical polluted city located in “2+26” city cluster in China North Plain in December 2017. The observation results illustrated that coal-fired plant can increase the PM_2.5 concentration by ~5% on monthly average in city scale. The impacts differed under various diffusion conditions. A three-dimensional Nested Air Quality Perdition Model (NAQPMS) with source apportionment was employed to reveal the impacts. The results indicated that the power plant had the greatest effect on regional air quality during severe pollution period while it was ignorable during the excellent dissipation period under the robust wind. PM_2.5 contributed by the power plant was below 150 m, 100 km far away, and about 5 μg m^-3 during light pollution period. When it came to accumulation period, the plume reached 500 m height, diffused to downwind area about 100 km away within half a day, and with a maximum contribution of 40 μg m^-3 to PM_2.5. The affected area extended further to 250 km in severe pollution period and the contribution to PM_2.5 was at least 10 μg m^-3 in different distances. The affected height was up to about 500 m with more than 10 μg m^-3 PM_2.5 mainly constrained below 150 meters. Overall, regional integrated control strategies should be taken for power plants in “2+26” city cluster during pollution episodes to further improve the air quality.