摘要：A haze episode occurred on 12 September 2009 in Shanghai, when the mass ratio of
PM1.0/PM2.5 (PM: particulate matter) reached 0.8. A similar variation of hygroscopic growth
factor distribution was observed for Aitken mode particles and accumulation
mode particles, implying that the enhancement of fine particles was caused by
local atmospheric processing. The hygroscopicity measurements in combination
with chemical analysis provided strong support for the significant contribution of
(NH4)2SO4 and
NH4NO3 to the haze episode.
The molar ratio of [NH4 + ]/([NO3 − ] + 2[SO42 − ]) rose up to 0.96, coincident with the large increase in
NH3 concentration, suggesting
that the available NH3 played a vital role in the enhancement of particulate sulfate and nitrate during the haze
episode.
