Long-range atmospheric transport of particulate Polycyclic Aromatic Hydrocarbons and the incursion of aerosols to the southeast Tibetan Plateau

The long range atmospheric transport of Polycyclic Aromatic Hydrocarbons (PAHs) from heavily polluted regions to remote areas has been well-known. However, there are limited studies focussing on the Tibetan Plateau (TP). To assess the temporal transport patterns of PAHs and particulate matters (PMs), a ground-based observation program (2008–2011) was conducted in the southeast TP. Relatively high atmospheric concentrations of particulate-PAHs (0.2–5.0 ng m−3, sum of 15 compounds) and Total suspended Particles (TSP, 4.1–46.7 μg m−3) were observed. Concentrations of particulate-PAHs/TSP exhibited seasonality with higher levels in the winter–spring season and lower levels in summer. Using the potential source contribution function model, the source region of both particulate-PAHs and particles was attributed to the Indo-Gangetic Plain (IGP), suggesting the co-transport of particulate-PAHs and aerosols. The aerosol incursion, penetrating the Himalayas and reaching the TP was further captured by Moderate Resolution Imaging Spectroradiometer and Cloud-Aerosol Lidar Infrared Pathfinder Satellite Observations. •Concentrations of particulate-PAHs were higher in the winter–spring season.•The source region of particulate-PAHs was the Indo-Gangetic Plain.•Smoke in the southern Himalayas could penetrate the barrier of Himalayas.