Tourism activities significantly contributed toatmospheric pollutants in a remote town of Tianshan revealed by the continuous observation of two years

Abstract

The large reduction in tourism activities in 2020 provided a unique opportunity to investigate their contribution on atmospheric pollutants in Bayanbulak, a remote town in Tianshan, China. In this scenic and sensitive region, we measured total suspended particulates (TSP) along with concentrations of polycyclic aromatic hydrocarbons (PAHs), organic carbon (OC), elemental carbon (EC) and water-soluble inorganic ions (WSIIs) during the lockdown in 2020 and compared these to levels in the pre-pandemic period of 2019. The study revealed significant reductions in PAHs, OC, EC, and some WSIIs concentrations during the tourist season (May–October) of 2020 compared with 2019, whereas variations between non-tourist seasons were less pronounced. Furthermore, by comparing pollutant characteristics in tourist seasons of these two years, we found that 5- and 6-ring groups were main PAH constituents in 2019, while 5- and 3-ring groups contributed more to total PAHs in 2020. OC/EC ratio increased from 2019 to 2020, indicating an increase of biomass burning contribution after the lockdown. Using positive matrix factorization, we determined that emissions from tourism-related transportation and combustion of natural gas and coal (mainly for cooking) contributed 21.9% and 46.6%, respectively, to certain atmospheric pollutants in 2019, whereas they decreased significantly to 3% and 19.4% in 2020 with dust and biomass contributions increased substantially. The levels of PAHs, OC, and EC from tourism-related sources were as high as 9.31 ng m−3, 1.28 μg m−3 and 0.11 μg m−3 and decreased by 54.37%, 25.16%, and 9.54%, respectively, compared to 2019. Hence, the impact of tourism must be considered during the assessment of local air pollutant emissions, particularly in remote areas.