Continuous appearance of fog and haze has become noticeable serious haze pollution in China. Recently, Prof. LI Zhengqiang and his team from the Institute of Remote Sensing and Digital Earth (RADI), found a typical submicron fine (SMF) particle mode which might be an important intermediate state in the fog-haze transformation process, and established a model for SMF mode. Their work published at Atmospheric Environment as Short Communication (doi:10.1016/j.atmosenv.2013.12.044).

The study finds that a stable and typical submicron fine mode exist during the transformation from larger fog droplets to smaller haze particles, with the volume distribution peak diameter of about 0.88μm, based on ground-based remote sensing in serious fog-haze pollution in January 2013.

SMF mode may exist in both formation and dissipation process of serious pollution related with fog/cloud, and the peak in SMF mode can maintain several hours, volume doubling or decreasing in the case of constant particle number concentration.

In addition, SMF mode was found in globally (e.g. India, Brazil and USA) similar pollution. The discovery indicated that SMF mode may be an important intermediate state in the fog-haze transformation.

The scientists also established a size distribution model for SMF mode, and found that the particles can not only lose water but also change their mixing form when transformed into stable haze particles, and therefore influence on characteristic of resulted haze pollution.

This study provides an important approach to observe the fog-haze transformation process, understand serious haze formation mechanism, and design haze prevention and control strategy. Related works were supported by Excellent Young Scientist Foundation of NSFC (No. 41222007), Key Research Program of the Ministry of Science and Technology of China.