2018 Yes https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6339187/ Barros, Nirmalla North America Modeling Carbon Monoxide (CO) Particulate Matter (PM) Volatile Organic Compounds (VOCs) Ozone (O3) Nitrogen Dioxide (NO2) Children School American indian/alaska native Air pollution Land use Land cover Closest emission sources were oil, gas, airport, and manufacturing facilities. Maximum annual outdoor air concentrations were measured for toluene at two schools (29 ppb and 15 ppb, 2011), located four miles from a solid waste landfill and eight miles from paperboard/saw mills. Maximum annual concentrations of metals in particulate matter 10 micrometers and smaller were highest for manganese (68 ng/m3, 2011). Schools were in mainly arid and heavily forested lands. Closest emission sources were predominantly off tribal lands. Measurements were limited (<30/year)