The Model of Aerosol Scattering Hygroscopic Growth During Autumn and Winter in Chengdu

Aerosol scattering hygroscopic growth has an important impact on the atmospheric environment. However, there is little relevant research on the west of Sichuan Province. In this study, the hourly atmospheric observations by nephelometer and aethalometer and the environmental and meteorological datasets of Chengdu from October to December 2017 were used. Based on above dataset which include atmospheric visibility, relative humidity (RH) and NO₂ mass concentration. Based on above datasets, the corresponding aerosol scattering hygroscopic growth factor f(RH) was calculated. Furthermore, the variations associated with RH were analyzed. The results show that firstly, quadratic polynomial is determined as the optimal aerosol scattering hygroscopic growth model through the comparisons between multi models; secondly, based on this optimal model, the f(RH) increased with RH, and the sharply increased point appears when the RH reached between 86% and 87%; thirdly, the f(RH) of Chengdu is less than that of Pearl River Delta, but it is generally greater than those of Beijing-Tianjin-Hebei region, Yangtze River Delta, as well as Brazil and Portugal.