Characterising personal, household, and community PM2.5 exposure in one urban and two rural communities in China

Background:Cooking and heating in households contribute importantly to air pollution exposure worldwide. However, there is insufficient investigation of measured fine particulate matter (PM2.5) exposure levels, variability, seasonality, and inter-spatial dynamics associated with these behaviours.Methods:We undertook parallel measurements of personal, household (kitchen and living room), and community PM2.5in summer (May-September 2017) and winter (November 2017-Janauary 2018) in ∼480 participants from one urban and two rural communities in China. These recorded ∼61,000-81,000 person-hours of processed data per microenvironment. Age- and sex-adjusted geometric means of PM2.5were calculated by key participant characteristics, overall and by season. Spearman correlation coefficients between PM2.5levels across different microenvironments were computed.Findings:Overall, 25.1% reported use of solid fuel for both cooking and heating. Solid fuel users had ∼90% higher personal and kitchen 24-hour average PM2.5exposure than clean fuel users. Similarly, they also had a greater increase (∼75% vs ∼20%) in personal and household PM2.5from summer to winter, whereas community levels of PM2.5were 2-3 times higher in winter regardless of fuel use. Compared with clean fuel users, solid fuel users had markedly higher weighted annual average PM2.5exposure at personal (77.8 [95% CI 71.1-85.2] vs ∼40 µg/m3), kitchen (103.7 [91.5-117.6] vs ∼50 µg/m3) and living room (62.0 [57.1-67.4] vs ∼40 µg/m3) microenvironments. There was a remarkable diurnal variability in PM2.5exposure among the participants, with 5-minute moving average 700-1,200µg/m3in typical meal times. Personal PM2.5was moderately correlated with living room (Spearman r: 0.64-0.66) and kitchen (0.52-0.59) levels, but only weakly correlated with community levels, especially in summer (0.15-0.34) and among solid fuel users (0.11-0.31).Conclusion:Solid fuel use for cooking and heating was associated with substantially higher personal and household PM2.5exposure than clean fuel users. Household PM2.5appeared a better proxy of personal exposure than community PM2.5in this setting.