Urban-rural disparity in global estimation of PM2 center dot 5 household air pollution and its attributable health burden

Background Polluting fuels and inefficient stove technologies are still a leading cause of premature deaths worldwide, particularly in low-income and middle-income countries. Previous studies of global household air pollution (HAP) have neither considered the estimation of PM2 center dot 5 at national level nor the corresponding attributable mortality burden. Additionally, the effects of climate and ambient air pollution on the global estimation of HAP-PM2 center dot 5 exposure for different urban and rural settings remain largely unknown. In this study, we include climatic effects to estimate the HAP-PM2 center dot 5 exposure from different fuel types and stove technologies in rural and urban settings separately and the related attributable global mortality burden. Methods Bayesian hierarchical models were developed to estimate an annual average HAP-PM2 center dot 5 personal exposure and HAP-PM2 center dot 5 indoor concentration (including both outdoor and indoor sources). Model variables were selected from sample data in 282 peer-reviewed studies drawn and updated from the WHO Global HAP dataset. The PM2 center dot 5 exposure coefficients from the developed model were applied to the external datasets to predict the HAP-PM2 center dot 5 exposure globally (personal exposure in 62 countries and indoor concentration in 69 countries). Attributable mortality rate was estimated using a comparative risk assessment approach. Using weighted averages, the national level 24 h average HAP-PM2 center dot 5 exposure due to polluting and clean fuels and related death rate per 100 000 population were estimated. Findings In 2020, household use of polluting solid fuels for cooking and heating led to a national-level average personal exposure of 151 mu g/m(3) (95% CI 133-169), with rural households having an average of 171 mu g/m(3) (153-189) and urban households an average of 92 mu g/m(3) (77-106). Use of clean fuels gave rise to a national-level average personal exposure of 69 mu g/m(3) (62-76), with a rural average of 76 mu g/m(3) (69-83) and an urban average of 49 mu g/m(3) (46-53). Personal exposure-attributable premature mortality (per 100 000 population) from the use of polluting solid fuels at national level was on average 78 (95% CI 69-87), with a rural average of 82 (73-90) and an urban average of 66 (57-75). The average attributable premature mortality (per 100 000 population) from the use of clean fuels at the national level is 62 (54-70), with a rural average of 66 (58-74) and an urban average of 52 (47-57). The estimated HAP-PM2 center dot 5 indoor concentration shows that the use of polluting solid fuels resulted in a national-level average of 412 mu g/m(3) (95% CI 353-471), with a rural average of 514 mu g/m(3) (446-582) and an urban average of 149 mu g/m(3) (126-173). The use of clean fuels (gas and electricity) led to an average PM2 center dot 5 indoor concentration of 135 mu g/m(3) (117-153), with a rural average of 174 mu g/m(3) (154-195) and an urban average of 71 mu g/m(3) (63-80). Using time-weighted HAP-PM2 center dot 5 indoor concentrations, the attributable premature death rate (per 100 000 population) from the use of polluting solid fuels at the national level is on average 78 (95% CI 72-84), the rural average being 84 (78-91) and the urban average 60 (54-66). From the use of clean fuels, the average attributable premature death rate (per 100 000 population) at the national level is 59 (53-64), the rural average being 68 (62-74) and the urban average 45 (41-50). Interpretation A shift from polluting to clean fuels can reduce the average PM2 center dot 5 personal exposure by 53% and thereby lower the death rate. For all fuel types, the estimated average HAP-PM2 center dot 5 personal exposure and indoor concentrations exceed the WHO's Interim Target-1 average annual threshold. Policy interventions are urgently needed to greatly increase the use of clean fuels and stove technologies by 2030 to achieve the goal of affordable clean energy access, as set by the UN in 2015, and address health inequities in urban-rural settings.

Automated summary

Using polluting fuels and inefficient stove technologies leads to premature deaths, especially in low-income and middle-income countries. This study estimates the exposure to PM2.5 from different fuel types and stove technologies in rural and urban settings, as well as the related mortality burden. The findings show that households using polluting solid fuels have an average personal exposure of 151 μg/m³ of PM2.5, while households using clean fuels have an average exposure of 69 μg/m³. The average premature mortality rate attributable to the use of polluting solid fuels is 78/100,000 population, while for clean fuels it is 62/100,000 population.