Leveraging Environmental data for Air Pollution exposure assessment in Epidemiology (LEAP-Epi) Team and South African Low-Cost Sensor Inter-Comparison Campaign (LCS-SA) Team 2021. Commentary: Opportunities for the application of low-cost sensors in epidemiological studies to advance evidence of air pollution impacts on human health. Clean Air Journal. 31, 1 (May 2021). DOI:https://doi.org/10.17159/caj/2021/31/1.11219.