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

Tis work was supported by Bloomberg Philanthropies through the Health Effects Institute, by the Climate Works Foundation, and by the Natural Sciences and Engineering Research Council (NSERC) of Canada. We thank the HERC labs for supplying filter weighing facilities. Data collection in Kanpur was supported by grant from the Indo-US Science and Technology Forum (IUSSTF) under real time air quality monitoring scheme. Data collection in Rehovot was supported in part by the Environmental Health Fund (Israel) and the Israel Science Foundation (grant #236/16). Partial support for the ITB site was by Ministry of Research, Technology & Higher Education, under World Class University (WCU) managed by Bandung Institute of Technology (ITB). The views expressed here are of authors and do not necessarily reflect those of NAS or USAID. The Singapore site was supported by the Singapore National Research Foundation (NRF) through the Singapore-MIT Alliance for Research and Technology (SMART), Center for Environmental Sensing and Modeling. The site in Atlanta was partially supported by NASA Applied Science Program (Grant # 80NSSC19K0191) and the Jet Propulsion Laboratory (Contract #1588347 and #1363692). All data are freely available as a public good at http://www.spartan-network.org. We welcome expression of interest to collaborate with this grass-roots network