Quantifying dust contribution to particulate matter in Central Asia: Insights from the elemental composition of PM2.5 and PM10 in Uzbekistan
Annotatsiya
Insufficient ground-based measurements are available to understand particulate matter (PM) in Central Asia, one of the major global dust source regions. Elemental characterization of PM is needed to examine dust contribution to PM and understand dust impacts in this region. We estimated dust concentrations using the first contemporary elemental composition data of PM 2.5 and PM 10 samples collected from an urban site in Uzbekistan during the 2023 dusty seasons and compared them to historical PM 2.5 samples from the dusty seasons of 2008–2010. The mean dust contribution to PM 2.5 during the 2023 dusty seasons was 33% (7.7 μg/m 3 ), comparable to 2008 (31%) but higher than in 2009 (20%) and 2010 (26%). A large dust event originating from the Kyzylkum Desert in 2023 and another from the Aralkum Desert in 2008 were identified by time series analysis of dust concentration, backward trajectory analysis, and satellite images. The two dust event days show lower Fe but higher Ca fractions in PM 2.5 than normal days. Compared to 2008–2010, elevated Zn concentrations were observed in 2023, likely driven by metalworking industries, transportation, and construction activities. These results provide insights into air pollution control in Central Asia and contribute to the understanding of dust composition, sources, and transport within the region. • Dust contributed an average of 33% to PM 2.5 during the dusty seasons of 2023. • Large dust events originating from Aralkum and Kyzylkum were identified. • The dust event days show higher Ca fractions in PM 2.5 than normal days. • The Zn concentration level was significantly higher in 2023 than in 2008–2010.