In situ observation of dust involved photochemistry over southern China

Heterogeneous reactions on dust particles have received a great deal of interest over the last decades, but focusing mostly on nighttime chemistry. Recent lab studies demonstrated several new photo-induced reactions (i.e. heterogeneous photochemistry) on dust surface. These processes suggest a potential of dust particles to influence the atmospheric photochemistry directly, but rarely observed in the real atmosphere. In this study, we report an in situ observation of several photochemical processes of HONO formation, new particle formation and growth under the condition of strong dust storms at a remote mountain site in southern China. Such dust involved photochemical processes were evidenced in situ, when dust storms, anthropogenic plumes from North China and biogenic emissions from southern China mix. This study provides unique in situ observations on heterogeneous photochemical processes in the real atmosphere, and suggests an unexpected impact of mineral dust on global climate and atmospheric environment.