Insights into the morphology, composition, and sources of atmospheric particulate matter on Mount Qomolangma (Everest)

Abstract

Aerosol category and its physicochemical properties are key factors influencing its climate and environmental effects. To further enhance our understanding of aerosols in the Himalayas-Tibetan Plateau region, atmospheric particulate matter samples were collected at three different altitudes on Mount Qomolangma (Everest). Using an automated scanning electron microscope system, the composition, size, and morphology of 52,349 particles were analyzed. The average mass concentrations of PM1, PM2.5, and PM10 were 0.678, 5.054, and 16.698 µg/m3, respectively. Aluminosilicate particles dominated the samples, accounting for 71.5 % to 82.8 % of PM10 mass and 34.7 % to 62.4 % of the particle number. Quartz particles, carbonate particles, metal oxides, and sulfates were also observed at different periods. Carbonaceous particles made up a significant portion of aerosols, comprising 2.1 % to 9.7 % of PM10 mass and 10.4 % to 45.4 % of particle number, with their concentration showing an upward trend with altitude. Small amounts of tar ball particles and fly ash particles were also observed, providing direct evidence of anthropogenic influences on high-altitude regions, even at altitudes exceeding 6000 m. The size distribution and abundance of different particle categories were closely related to the transport trajectories of air masses. The morphology of different particle categories varied, with fly ash particles mainly spherical and carbonaceous particles exhibiting higher irregularity.