Source and composition of aerosol elements in Shanghai: Evidence from long-term hourly Xact dataset

July 30, 2026

Trace elements in ambient particles influence tropospheric chemistry, climate, and human health. This study investigates the spatiotemporal evolution and health implications of PM₂.₅-bound metals in Shanghai, a coastal megacity. High-time-resolution elemental data collected at two representative sites, Pudong (PD) and Qingpu (QP), were compared between 2018 and 2023. PM₂.₅ mass concentrations and ship-emission tracers (e.g., V and Ni) declined under increasingly stringent emission controls, whereas the relative mass fractions of typical non-exhaust-emission (NEE) tracers (e.g., Cu, Fe, Zn, and Ba) increased or remained elevated during a period of rapid vehicle-fleet electrification. Diurnal patterns of near-road NEE tracers identified by bivariate polar k-means clustering showed distinct morning and evening rush-hour peaks. Although average inhalation risks decreased, wind-sector-resolved analysis identified localized hotspots of elevated carcinogenic and non-carcinogenic risk that overlapped spatially with areas showing enhanced NEE-to-PM₂.₅ ratios from 2018 to 2023. Integration with urban Point of Interest (POI) data further showed that these risk hotspots were concentrated along traffic networks and in adjacent residential zones. The results indicate that air-quality management in densely populated megacities should address NEE as tailpipe emissions decline.

Authors in the community:

• 

  Y

  Yanjie Lei

  ist1115667

Supervisors of this institution:

• 

  A

  Ana Sofia Oliveira Henriques Moita

  ist31614

other-engineering-and-technologies - Other engineering and technologies

eng - English

Instituto Superior Técnico