Secondary Formation of Atmospheric Brown Carbon in China Haze: Implication for an Enhancing Role of Ammonia.

ABSTRACT: Optical characteristics and molecular compositions of brown carbon (BrC) were investigated during winter 2019 at a rural site of China with a focus on nitro-aromatic compounds (NACs) and imidazoles (IMs). The abundance of gaseous nitrophenols relative to CO during the campaign maximized at noontime, being similar to O₃, while the particulate NACs during the haze periods strongly correlated with toluene and NO₂, suggesting that NACs in the region are largely formed from the gas-phase photooxidation. Strong correlations of particulate IMs in the dry haze periods with the mass ratio of EC/PM_2.5 and the concentration of levoglucosan were observed, indicating that IMs during the dry events are largely derived from biomass burning emissions. However, an increase

SUBMITTER: Liu X 

PROVIDER: S-EPMC10399565 | biostudies-literature | 2023 Aug

REPOSITORIES: biostudies-literature