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Abstract:
latinum group element (PGE) is among the emerging airborne contaminants mainly emitting from automobile catalysts. The ambient PGE concentration in Asia is expected to rise due to an increase in vehicle sales over the last two decades. Of all the Asian countries, the automobile industry in India has grown at a spectacular rate (> 50% in the last 10 years) and is expected to become a hotspot of global PGE contamination. However, the Indian subcontinent can be regarded as a “white spot” on the global PGE contamination map, indicating the presence of very limited field data. Here, we report the annual time-series record of PGE concentrations of the airborne particulate matter <10-micron-sized (PM10) collected from a high-altitude remote site in the central Himalaya that draws a significant fraction of air mass from the heavily polluted Indo-Gangetic Plain (IGP). The time-series record reveals that the PGE concentrations in PM10 are amongst the lowest recorded levels globally, lack seasonal variability, and are derived from aged catalyst and coal combustion products. We conclude that the annual average Pt, Pd, Rh, and Ru concentrations of 0.88 ± 0.57, 2.07 ± 1.75, 0.14 ± 0.1, and 0.16 ± 0.08 pg m−3, respectively, would serve as a baseline concentration in PM10 to judge the future magnitude of PGE contamination in the Indian subcontinent.
