Characterization of submicron aerosols and effect on visibility during a severe haze-fog episode in Yangtze River Delta, China

A severe haze-fog event on Jan. 14-17 was discussed in more detail as a case study. Two episodes were chosen to show that nitrate and organics dominated the aerosol component during the severe haze-fog episode and were related to secondary aerosol formation and air mass origin. Nitrate played a more dominant role than sulfate in heavy haze formation in the YRD region, which was different from the North China Plain region.