Size distribution of particle-phase sugar and nitrophenol tracers during severe urban haze episodes in Shanghai

In this study, measurements of size-resolved sugar and nitrophenol concentrations and their distributions during Shanghai haze episodes were performed. The primary goal was to track their possible source categories and investigate the contribution of biological and biomass burning aerosols to urban haze events through regional transport. The results showed that levoglucosan had the highest concentration (40–852 ng m−3) followed by 4-nitrophenol (151–768 ng m−3), sucrose (38–380 ng m−3), 4-nitrocatechol (22–154 ng m−3), and mannitol (5–160 ng m−3). Size distributions exhibited over 90% of levoglucosan and 4-nitrocatechol to the total accumulated in the fine-particle size fraction (2.1 μm), which can be correlated with emissions from local sources (biological emission). Principal component analysis (PCA) and positive matrix factorization (PMF) revealed four probable sources (biomass burning: 28%, airborne pollen: 25%, fungal spores: 24%, and combustion emission: 23%) responsible for urban haze events. Taken together, these findings provide useful insight into size-resolved source apportionment analysis via molecular markers for urban haze pollution events in Shanghai. •Size-resolved aerosol samples were collected in Shanghai during the haze events.•Levoglucosan, 4-nitrocatechol, OC, and EC dominated in fine particles.•Sucrose, fructose and glucose dominated in coarse particles.•Sugar alcohols and some nitrophenols presented bimodal distribution.•The major sources were biomass burning, combustion, and biological emission.