The Air Quality Monitoring Team (AQMT) at UC Davis has operated the Interagency Monitoring of Protected Visual Environments (IMPROVE) ambient speciated particulate monitoring network since its inception in 1988. Beginning in 2015, AQMT took on the laboratory analysis and data handling for the Chemical Speciation Network (CSN). These two networks encompass over 300 sites delivering over 60 PM2.5 species across the country every third day.
Zhang, Y., K. Vijayaraghavan, X.-Y. Wen, H. E. Snell, and M. Z. Jacobson (2009), Probing into regional ozone and particulate matter pollution in the United States: 1. A 1 year CMAQ simulation and evaluation using surface and satellite data, J. Geophys. Res., 114, D22304.