Pollution characteristics and potential sources of Peroxyacetyl Nitrate in a petrochemical industrialized City, Northwest China.

Peroxyacetyl Nitrate (CHC(O)ONO, PAN), a typical secondary product of photochemical reactions, is well known to be a better photochemical indicator due to the only secondary photochemical source in the troposphere. Studies on PAN pollution are sparse in northwest China, resulting in a limited understanding of photochemical pollution in recent years. Herein, the measurement of PAN, O, volatile organic compounds (VOCs), NO, other related species, and meteorological parameters were conducted from May 1 to August 31, 2022, at an urban site in Lanzhou.