Summertime PM 2.5 ionic species in four major cities of China: nitrate formation in an ammonia-deficient atmosphere

Abstract. Strong atmospheric photochemistry in summer can produce a significant amount of secondary aerosols, which may have a large impact on regional air quality and visibility. In the study reported herein, we analyzed sulfate, nitrate, and ammonium in PM2.5 samples collected using a 24-h filter ... View More