Temporal Variations, Source Attributions, and Health Risks of PM2.5-Bound Trace Elements in a Megacity in Central China

Trace elements bound to PM2.5 constitute crucial factors increasing human health risks. To optimize health-oriented air quality management strategies for industrial cities, this study monitored major trace elements in PM2.5 in Wuhan, China, from June 2023 to May 2024. During the study period, the mean concentration of trace elements was 3290 ± 2270 ng/m3, comprising 93.9% crustal elements and 6.1% heavy metals. The positive matrix factorization model identified fugitive dust as the primary source of trace elements, with a mean contribution of 35.6%, followed by traffic emissions (21.8%), industrial emissions (19.1%), biomass and waste incineration (12.3%), and coal combustion (11.1%). Health risk assessment revealed that the cumulative non-carcinogenic and carcinogenic risks of trace elements via inhalation exposure exceeded acceptable levels for both local children and adults, with Mn, As, and Cr as key risk factors. Although coal combustion contributed less to trace element concentrations than other sources, it was the largest contributor to non-carcinogenic and carcinogenic risks, followed by fugitive dust and traffic emissions. These results suggest that trace element pollution control in Wuhan should prioritize reducing coal combustion emissions, while emphasizing the critical importance of sustained traffic regulation and fugitive dust suppression to improve air quality and protect public health.