2017 Yes https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5219730/ Nkosi, Vusumuzi Africa Observational Epidemiology Study Students Middle/Jr High (6-8) Particulate Matter (PM) Mine dumps School Air pollution Asthma South Africa The level of outdoor PM10 for exposed was 16.42 vs. 11.47 mg.m−3 for the unexposed communities (p < 0.001). The outdoor SO2 for exposed was 0.02 ppb vs. 0.01 ppb for unexposed communities (p < 0.001). Indoor respirable dust in the classroom differed significantly between exposed (0.17 mg.m−3) vs. unexposed (0.01 mg.m−3) children with asthma at each school (p < 0.001).