Tracking supply-chain atmospheric emissions of multiple hazardous trace elements in China's cement industry.

Cement industry plays a pivotal role in hazardous trace element (HTE) emissions. However, existing researches largely concentrated on Hg, with limited attention paid to other trace elements. Here, we developed a bottom-up, supply-chain emission framework to track HTE emissions from China's cement industry. The estimated national emissions of As, Cd, Cr, Ni, Mn, and Pb in 2020 were 127.6 tons, 19.2 tons, 181.5 tons, 209.2 tons, 664.7 tons and 601.1 tons, respectively. Production stage contributed over 90% of total emissions. Specifically, raw material calcination dominated the emissions of As, Cd, Mn, and Pb; Ni emissions were predominantly from fuel combustion, whereas Cr emissions were jointly contributed by fuel combustion and raw material calcination. We further found that, by 2060, integrated mitigation measures reduced HTE emissions by 55-89%. The distinct source patterns of various HTEs led to element specific co-benefits of different control measures. Notably, we observed that inter-provincial cement trade induced a net increase in national HTE emissions when compared to a "no trade" scenario. Additionally, consumption-based accounting reallocated emission responsibility from producing to consuming provinces. These findings highlight that a full-process and consumption-based accounting framework are essential for effectively mitigating HTE emissions from China's cement industry.