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The Household Air Pollution Intervention Network trial is a multi-country study on the effects of a liquefied petroleum gas (LPG) stove and fuel distribution intervention on women's and children's health. There is limited data on exposure reductions achieved by switching from solid to clean cooking fuels in rural settings across multiple countries. As formative research in 2017, we recruited pregnant women and characterized the impact of the intervention on personal exposures and kitchen levels of fine particulate matter (PM 2.5 ) in Guatemala, India, and Rwanda. Forty pregnant women were enrolled in each site. We measured cooking area concentrations of and personal exposures to PM 2.5 for 24 or 48 h using gravimetric-based PM 2.5 samplers at baseline and two follow-ups over two months after delivery of an LPG cookstove and free fuel supply. Mixed models were used to estimate PM 2.5 reductions. Median kitchen PM 2.5 concentrations were 296 μg/m 3 at baseline (interquartile range, IQR: 158–507), 24 μg/m 3 at first follow-up (IQR: 18–37), and 23 μg/m 3 at second follow-up (IQR: 14–37). Median personal exposures to PM 2.5 were 134 μg/m 3 at baseline (IQR: 71–224), 35 μg/m 3 at first follow-up (IQR: 23–51), and 32 μg/m 3 at second follow-up (IQR: 23–47). Overall, the LPG intervention was associated with a 92% (95% confidence interval (CI): 90–94%) reduction in kitchen PM 2.5 concentrations and a 74% (95% CI: 70–79%) reduction in personal PM 2.5 exposures. Results were similar for each site. Conclusions The intervention was associated with substantial reductions in kitchen and personal PM 2.5 overall and in all sites. Results suggest LPG interventions in these rural settings may lower exposures to the WHO annual interim target-1 of 35 μg/m 3 . The range of exposure contrasts falls on steep sections of estimated exposure-response curves for birthweight, blood pressure, and acute lower respiratory infections, implying potentially important health benefits when transitioning from solid fuels to LPG.

The Tamil Nadu Air Pollution and Health Effects study (TAPHE-2) aims to evaluate the relationship between air pollution and birth outcome in a rural-urban cohort of 300 pregnant women. Due to COVID-19 related lockdowns, some TAPHE-2 activities were delayed; however, continuous indoor and outdoor air quality data were collected in and around Chennai, India. We report here the impact of graded COVID-19 lockdown on indoor particulate matter (PM2.5 and PM10) levels based on calibrated data from affordable real-time PM sensors called atmos™ and ambient PM levels from publicly available regulatory monitors. The study period was between 11 March and 30 June 2020 (i.e., 100 days of continuous monitoring), which coincided with four phases of a nationwide graded lockdown. Field calibration coefficients for the atmos PM were derived by collocating them with reference-grade PM monitors. The normalized root mean square error (NRMSE) of the atmos hourly PM2.5 (PM10) improved from 41% to 15% (33% to 18%) after applying the field calibration coefficients. Lockdowns resulted in significant reductions in indoor and ambient PM levels, with the highest reduction observed during lockdown phase 2 (L2) and phase 3 (L3). Reductions as high as 70%, 91%, and 62% were observed in ambient PM2.5, indoor PM2.5, and indoor PM10 relative to pre-lockdown levels (PL), respectively. The indoor PM2.5/PM10 ratio decreased during the lockdown, suggesting a decline in the fine mode dominance in PM10. The indoor-to-outdoor (I/O) ratios in PM2.5 marginally increased during L1, L2, and L3 phases compared to that of PL levels, suggesting an uneven reduction in indoor and ambient PM2.5 levels during the lockdown.

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Highlights Cross-validation of analytical techniques for 1-hydroxypyrene and 2-naphthol. Good agreement between low cost HPLC fluorescence (HPLC-FLD) and LC-MSMS methods. HPLC-FLD method was highly sensitive to 2NAP compared to LC-MSMS. HPLC-FLD showed large bias for 2NAP with LC-MSMS at levels greater than 20 ng/mL. HPLC-FLD is a cost-effective and reliable analytical method for low-and middle-income countries.