Household air pollution contributes substantially to ambient air pollution. Estimates of this contribution range between 20 and 45% globally, with large spatial heterogeneity. Reducing household air pollution from solid fuel use thus has benefits across scales — it benefits people in homes who rely on these fuels, but also provides benefits to communities and airsheds by reducing ambient air pollution levels.

Interventions to decrease household air pollution exposures have a long history, ranging from so-called ‘improved’ biomass stoves that burn available fuels cleanly to clean fuels, like liquefied petroleum gas and ethanol, to electricity. Our group works on evaluating interventions from cost, environmental, climate, and health perspectives.

We engage in policy-oriented experiments to help justify continued investment in clean household energy. These range from cost-effectiveness analyses to behavior change campaigns to pragmatic, scalable policies targeting the most vulnerable populations.

Our group makes measurements to estimate exposure and, in doing so, inform policies, evaluate interventions, and help provide evidence of potential health risk. Where instrumentation is lacking, we develop our own or adapt technologies used in other sectors and disciplines.

Mollinedo, E., McCracken, J. P., Johnson, M., Piedrahita, R., Pillarisetti, A., Waller, L. A., Wang, J., Thompson, L. M., Diaz-Artiga, A., de Leon, O., Ramirez, A., Polanco, A., Campbell, D., Kearns, K. A., Kremer, J., Nicolaou, L., Clark, M. L., Balakrishnan, K., Rosa, G., … Naeher, L. P. (2025). Comparing Performance and Reliability of Collocated Enhanced Children’s MicroPEM (ECM) on Gravimetric and Nephelometric PM2.5 Personal Exposure Samples in Field Measurements in Rural Guatemala. In N. B. Dhital (Ed.), Indoor Air (Vol. 2025, Issue 1). Wiley. https://doi.org/10.1155/ina/8812602

With Lisa Thompson (Emory), Johannes Urpelainen (Johns Hopkins), Carlos Gould (Columbia), and Morsel Research and Development (Uttar Pradesh, India)

India has undergone a dramatic household energy transformation in recent years, driven by government initiatives to increase clean fuel access. These improvements have not led to complete transitions to clean cooking, with most households continuing regular biomass use, a trend that may be exacerbated by the COVID‐19 pandemic. We leverage and extend a recently completed energy survey of 1440 households in rural Jharkhand by deploying a follow‐up, telephone‐based questionnaire multiple times over the next year, enabling analysis of how COVID‐19 and stay‐at‐home orders alter energy use behaviors. Findings from this longitudinal study will help (1) understand drivers of stacking or exclusive LPG or biomass use; (2) provide insights into how resilient household energy use patterns are to sudden economic and social shocks; and (3) establish guidance that may inform planning for the next pandemic or other unexpected shock.

The Household Air Pollution Intervention Network (HAPIN) Trial is an international multi-center study aimed at assessing the impact of a liquefied petroleum gas (LPG) cooking stove and fuel intervention on health. HAPIN Trial centers are located in four countries: Guatemala, India, Peru and Rwanda.

The HAPIN Trial was launched in 2017 with formative research. Main trial enrollment started in 2018 and follow-up of participants ended in September 2021. More than 7,200 study participants were enrolled and will help the HAPIN Trial find answers to questions about LPG cookstoves and health. Currently the investigators are analyzing data for the primary outcomes: low birth weight, severe pneumonia incidence, and stunting in the child, and blood pressure in the older adult woman. Secondary outcomes include preterm birth and child development in the child, maternal blood pressure during pregnancy, and endothelial function, respiratory impairment, atherosclerosis, carcinogenic metabolites, and quality of life in the older adult woman. The team has been publishing manuscripts throughout project implementation.

The trial is funded by the National Institutes of Health (NIH) and the Bill & Melinda Gates Foundation. Participating NIH components are the National Heart, Lung, and Blood Institute (NHLBI), the National Cancer Institute, the Eunice Kennedy Shriver National Institute of Child Health and Human Development, the National Institute of Environmental Health Sciences, the NIH Common Fund of the NIH Office of the Director, and the Fogarty International Center. NHLBI leads administration of the trial on behalf of the consortium. The Global LPG Partnership provides expert advice. We are thankful for the guidance of our advisory committee: Patrick Brysse, Donna Spiegelman, and Joel Kaufman.

Weltman, R. M., Edwards, R. D., Staimer, N., Pillarisetti, A., Arora, N. K., & Nizkorodov, S. A. (2025). Ethyne Furan Ratios as Indicators of High and Low Temperature p-PAH Emissions from Household Stoves in Haryana India. In Atmosphere (Vol. 16, Issue 2, p. 121). MDPI AG. https://doi.org/10.3390/atmos16020121

Karakwende, P., Checkley, W., Chen, Y., Clark, M. L., Clasen, T., Dusabimana, E., Jabbarzadeh, S., Johnson, M., Kalisa, E., Kirby, M., Naher, L., Ndagijimana, F., Ndikubwimana, A., Ntakirutimana, T., Ntivuguruzwa, J. de D., Peel, J. L., Piedrahita, R., Pillarisetti, A., … Rosa, G. (2025). Predictors of Personal Exposure to Fine Particulate Matter, Black Carbon, and Carbon Monoxide among Pregnant Women in Rwanda: Baseline Data from the HAPIN Trial. In Journal of Health and Pollution (Vol. 13, Issue 1). Environmental Health Perspectives. https://doi.org/10.1289/jhp1049

The recent Air Pollution Special Issue (Science 385) does a laudable job highlighting the global scientific community’s ability to quantify air pollution and its impacts and translate findings into policy-relevant recommendations. We contend, however, that it gives insufficient consideration to one of the oldest and leading sources of health-damaging pollution: cooking and heating with solid fuels (wood, dung, charcoal, coal, crop residues). ~3 million deaths yearly are attributable to the resulting household air pollution, which also contributes to climate change (1).

How bad is the air pollution associated with solid fuel use? Of ~12,000 PM_2.5 measurements made in households or on individuals using solid fuels, 1% were at or below the annual WHO Interim Target 1 guideline value of 35 µg/m³ (2). None attained the guideline value of 5 ug/m³. In other words, we expect that none of the 3 billion people without access to clean household energy experience air quality that satisfies the WHO guideline.

Advances in lower-cost sensing, as discussed in Apte et al (Science 385, 380-385), have enabled better resolved air pollution estimates and novel justice-focused analyses. They have not been widely applied in rural communities, especially indoors among households using solid fuels. Similarly, the goal of universal clean air, as discussed by Huang et al (Science 385, 386-390), cannot be met without commitment to reducing inequities in the impacts of household air pollution in low- and middle-income countries (LMICs).

Cleaner biomass alternatives—gas and electricity—have been available for decades and are commonplace among wealthier households in LMICs and widely in developed nations. While access to these cleaner technologies is increasing, their exclusive use lags in LMICs due to cost, availability, and reliability of supply (3). Global momentum to ban fossil fuel use has affected support for scaling clean household energy in LMICs, even while fossil fuels continue to power the economies of developed nations and the homes of their citizens. Without drastic policy measures to enable near-term clean energy transitions, which likely includes LPG, we run the risk of exacerbating exposure and health inequities among vulnerable communities (4).

Policies reducing HAP have many benefits: decreased exposure of household members by eliminating solid fuel use (5); reduced community exposures by removing many point sources; and improved air quality for entire airsheds (6). Efforts to improve measurement of HAP exposures and of rural air pollution similarly serve multiple purposes: they provide an important baseline of pollution people actually experience; they enable calibration of model- or satellite- based pollution estimates; and they enable accountability studies of policies that may improve ambient air (e.g. programs transitioning from biomass to gas or electricity).

No global health discourse on air pollution can be complete without adequate emphasis on household air pollution exposures that impact the poorest three billion with limited bargaining power for energy or health equity. We implore continued emphasis on this public health risk in every forum concerned with air pollution and health.

References
1. Health Effects Institute. “State of Global Air 2024.” Special Report.(Boston, MA:Health Effects Institute., 2024.
2. M. Shupler, K. Balakrishnan, S. Ghosh, G. Thangavel, S. Stroud-Drinkwater, H. Adair-Rohani, J. Lewis, S. Mehta, M. Brauer, Global household air pollution database: Kitchen concentrations and personal exposures of particulate matter and carbon monoxide. Data in Brief 21, 1292–1295 (2018).
3. E. Puzzolo, D. Pope, D. Stanistreet, E. A. Rehfuess, N. G. Bruce, Clean fuels for resource-poor settings: A systematic review of barriers and enablers to adoption and sustained use. Environmental Research 146, 218–234 (2016).
4. C. F. Gould, R. Bailis, K. Balakrishnan, M. Burke, S. Espinoza, S. Mehta, S. B. Schlesinger, J. R. Suarez-Lopez, A. Pillarisetti, In praise of cooking gas subsidies: transitional fuels to advance health and equity *. Environ. Res. Lett. 19, 081002 (2024).
5. M. Johnson, A. Pillarisetti, R. Piedrahita, K. Balakrishnan, J. L. Peel, K. Steenland, L. J. Underhill, G. Rosa, M. A. Kirby, A. Díaz-Artiga, J. McCracken, M. L. Clark, L. Waller, H. H. Chang, J. Wang, E. Dusabimana, F. Ndagijimana, S. Sambandam, K. Mukhopadhyay, K. A. Kearns, D. Campbell, J. Kremer, J. P. Rosenthal, W. Checkley, T. Clasen, L. Naeher, and the Household Air Pollution Intervention Network (HAPIN) Trial Investigators, Exposure Contrasts of Pregnant Women during the Household Air Pollution Intervention Network Randomized Controlled Trial. Environ Health Perspect 130, 097005 (2022).
6. S. Chowdhury, S. Dey, S. Guttikunda, A. Pillarisetti, K. R. Smith, L. Di Girolamo, Indian annual ambient air quality standard is achievable by completely mitigating emissions from household sources. Proc Natl Acad Sci USA 116, 10711 (2019).

by Ajay Pillarisetti^1*, Sumi Mehta², Kalpana Balakrishnan^3
1 School of Public Health, University of California, Berkeley; Berkeley, USA
² Vital Strategies; New York, USA
³ Department of Environmental Health Engineering, Faculty of Public Health, Sri Ramachandra, Institute of Higher Education and Research; Chennai, India

rejected as a letter to the editor at Science

Rajamani, K. D., Sambandam, S., Mukhopadhyay, K., Puttaswamy, N., Thangavel, G., Natesan, D., Ramasamy, R., Sendhil, S., Natarajan, A., Aravindalochan, V., Pillarisetti, A., Johnson, M., Rosenthal, J., Steenland, K., Piedhrahita, R., Peel, J., Clark, M. L., Boyd Barr, D., Rajkumar, S., … Balakrishnan, K. (2022). Visualizing Field Data Collection Procedures of Exposure and Biomarker Assessments for the Household Air Pollution Intervention Network Trial in India. In Journal of Visualized Experiments (Issue 190). MyJove Corporation. https://doi.org/10.3791/64144

Steenland, K., Pillarisetti, A., Johnson, M., Rosenthal, J., Balakrishnan, K., Underhill, L., Thompson, L., McCracken, J., Waller, L., Nicolaou, L., Clark, M., Checkley, W., Peel, J., & Clasen, T. (2025). Optimizing Exposure Measures in Large-Scale Household Air Pollution Studies: Results from the Multicountry HAPIN Trial. In Environmental Science & Technology (Vol. 59, Issue 3, pp. 1693–1699). American Chemical Society (ACS). https://doi.org/10.1021/acs.est.4c08052

Raheel, H., Sinharoy, S., Diaz-Artiga, A., Garg, S. S., Pillarisetti, A., Balakrishnan, K., Chiang, M., Lovvorn, A., Kirby, M., Ramakrishnan, U., Jabbarzadeh, S., Mukeshimana, A., Johnson, M., McCracken, J. P., Naeher, L. P., Rosa, G., Wang, J., Rosenthal, J., Checkley, W., … Thompson, L. M. (2025). Effects of a liquefied petroleum gas stove and fuel intervention on head circumference and length at birth: A multi-country household air pollution intervention network (HAPIN) trial. In Environment International (Vol. 195, p. 109211). Elsevier BV. https://doi.org/10.1016/j.envint.2024.109211

This research quantifies the contribution of households to ambient air pollution in North India by (1) updating and improving existing emissions inventories through activity-based modeling at high temporal and spatial resolution, (2) providing field-based emissions of SVOCs and other ozone precursors to, for the first time, model the contribution of household air pollution to regional secondary particle formation; and (3) monitoring rural ambient and near-home concentrations of and personal exposures to PM2.5. Modeling efforts will enable manipulation of various sources and emission rates, across a variety of relevant policy scenarios, enabling estimation of how certain initiatives may impact air pollution at varying scales.

This project leverages a multi-year collaboration between University of California Berkeley and INCLEN, the International Clinical Epidemiology Network (New Delhi, India). INCLEN runs a large demographic and environmental surveillance site ~75 kilometers south of Delhi; their activities span over 50 villages covering approximately 200,000 individuals. While relatively close to Delhi, most households in the area rely on brushwood and dung as primary household fuels. The entire region is prone to low, ground-level inversions in the winter, resulting in especially high PM concentrations between November and February.

Study findings have been disseminated to local stakeholders, policy makers, members of relevant ministries, environmental health practitioners, and other researchers through journal articles.