BACKGROUND

Cooking and heating in households contribute importantly to air pollution exposure worldwide. However, there is insufficient investigation of measured fine particulate matter (PM) 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 PM in summer (May-September 2017) and winter (November 2017-Janauary 2018) in 477 participants from one urban and two rural communities in China. After stringent data cleaning, there were 67,326-80,980 person-hours (n = 441; n = 384; n = 364; 307 had repeated PM data in both seasons) of processed data per microenvironment. Age- and sex-adjusted geometric means of PM were calculated by key participant characteristics, overall and by season. Spearman correlation coefficients between PM levels across different microenvironments were computed.

FINDINGS

Overall, 26.4 % reported use of solid fuel for both cooking and heating. Solid fuel users had 92 % higher personal and kitchen 24-h average PM exposure than clean fuel users. Similarly, they also had a greater increase (83 % vs 26 %) in personal and household PM from summer to winter, whereas community levels of PM were 2-4 times higher in winter across different fuel categories. Compared with clean fuel users, solid fuel users had markedly higher weighted annual average PM exposure at personal (78.2 [95 % CI 71.6-85.3] μg/m vs 41.6 [37.3-46.5] μg/m), kitchen (102.4 [90.4-116.0] μg/m vs 52.3 [44.8-61.2] μg/m) and living room (62.1 [57.3-67.3] μg/m vs 41.0 [37.1-45.3] μg/m) microenvironments. There was a remarkable diurnal variability in PM exposure among the participants, with 5-min moving average from 10 μg/m to 700-1200 μg/m across different microenvironments. Personal PM was 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 PM exposure than clean fuel users. Household PM appeared a better proxy of personal exposure than community PM.