Large global variations in measured airborne metal concentrations driven by anthropogenic sources

PM2.5 filter samples (N=800) from 19 globally distributed SPARTAN sites collected between January 2013 and April 2019 were analyzed for particulate mass and trace metal content to assess spatial variability and anthropogenic influences on airborne metals. Metal concentrations varied strongly across sites and were largely driven by anthropogenic activities, with PM2.5 levels of Pb, As, Cr, and Zn enriched by factors of 100–3000 relative to crustal abundances at some locations. Levels of metals in PM2.5 and PM10 exceeded health guidelines at multiple sites: Dhaka and Kanpur exceeded the US NAAQS 3‑month lead standard (150 ng/m³), and annual mean arsenic concentrations approached or exceeded the WHO 1:100,000 excess lifetime cancer risk level (6.6 ng/m³) at Kanpur, Hanoi, Beijing, and Dhaka. These results highlight high concentrations of potentially harmful metals in densely populated cities and motivate expanded measurements and analyses.

Jacob McNeill, Graydon Snider, Crystal L. Weagle, Brenna Walsh, Paul Bissonnette, Emily Stone, Ihab Abboud, Clement Akoshile, Nguyen Xuan Anh, Rajasekhar Balasubramanian, Jeffrey R. Brook, Craig Coburn, Aaron Cohen, Jinlu Dong, Graham Gagnon, Rebecca M. Garland, Kebin He, Brent N. Holben, Ralph Kahn, Jong Sung Kim, Nofel Lagrosas, Puji Lestari, Yang Liu, Farah Jeba, Khaled Shaifullah Joy, J. Vanderlei Martins, Amit Misra, Leslie K. Norford, Eduardo J. Quel, Abdus Salam, Bret Schichtel, S. N. Tripathi, Chien Wang, Qiang Zhang, Michael Brauer, Mark D. Gibson, Yinon Rudich, Randall V. Martin