01511nas a2200253   4500000000100000000000100001008004100002100001500043700001700058700001900075700001700094700001700111700001500128700001800143700001900161700001600180700001600196700002000212245014200232856004600374490000700420520081600427022001401243       2020                            d1 aLara Clark1 aV. Sreekanth1 aBujin Bekbulat1 aMichael Baum1 aSonglin Yang1 aPao Baylon1 aTimothy Gould1 aTimothy Larson1 aEdmund Seto1 aChris Space1 aJulian Marshall00aDeveloping a Low-Cost Passive Method for Long-Term Average Levels of Light-Absorbing Carbon Air Pollution in Polluted Indoor Environments  uhttps://www.mdpi.com/1424-8220/20/12/34170 v203 aWe propose a low-cost passive method for monitoring long-term average levels of light-absorbing carbon air pollution in polluted indoor environments. Building on prior work, the method here estimates the change in reflectance of a passively exposed surface through analysis of digital images. To determine reproducibility and limits of detection, we tested low-cost passive samplers with exposure to kerosene smoke in the laboratory and to environmental pollution in 20 indoor locations. Preliminary results suggest robust reproducibility (r = 0.99) and limits of detection appropriate for longer-term (~1–3 months) monitoring in households that use solid fuels. The results here suggest high precision; further testing involving “gold standard” measurements is needed to investigate accuracy.  a1424-8220