Physical and chemical properties of PM in Delhi: A comparison between clean and polluted days.

Considering the significance of PM aerosol in assessing health impacts of air pollution, an extensive analysis of PM samples collected at an urban site in Delhi is presented in this study. Overall, PM contributed to about 50 % of PM mass which is alarming especially in Delhi where particle mass loadings are usually higher than prescribed limits. Major portion of PM consisted of organic matter (OM) that formed nearly 47 % of PM mass.

Abundance, chemical structure, and light absorption properties of humic-like substances (HULIS) and other organic fractions of forest aerosols in Hokkaido.

Atmospheric organic aerosol (OA) are considered as a significant contributor to the light absorption of OA, but its relationship with abundance, composition and sources are not understood well. In this study, the abundance, chemical structural characteristics, and light absorption property of HULIS and other low-to-high polar organics in PM collected in Tomakomai Experimental Forest (TOEF) were investigated with consideration of their possible sources. HULIS were the most abundant (51%), and correlation analysis revealed that biogenic secondary organic aerosols significantly contribute to HULIS.