Comparison of indoor and outdoor oxidative potential of PM < sub > 2.5 < /sub > : pollution levels, temporal patterns, and key constituents

We examined pollution levels, temporal variations, and key constituents of PM2.5 OP by DTT assay in both indoor and outdoor environments in Nanjing, China, for over one year. Outdoor OPM (mass-normalized OP characterizes toxicity) and OPV (volume-based OP characterizes overall oxidative burden) in Nanjing were at a medium level compared to results reported for twenty-seven cities. Although PM2.5 mass concentration consistently decreased during outdoor-to-indoor transport, OPM varied by a factor of up to 2 in either direction, indicating a change of PM2.5's ability to disrupt oxidative-reductive balance. Temporally, both outdoor and indoor OPM exhibited a significant seasonality pattern (P < 0.01) as autumn > summer > spring > winter. Outdoor and indoor daytime-nighttime OPV and OPM are fluctuating within two-fold range. In addition, the change in water-soluble Fe had the highest correlation coefficient (P < 0.05) with ΔOPM (ΔOPM = OPM, in-OPM, out) among constituents measured here. Our results suggest that development of mitigation strategies take indoor PM2.5's OP into account, instead of outdoors only, since they differ.PMID:34118656 | DOI:10.1016/j.envint.2021.106684
Source: Environment International - Category: Environmental Health Authors: Source Type: research