Chronic household air pollution and exposure patterns among Himalayan nomads

Catlin I Powers; Linyan Li; Majid Ezzati; James P Butler; Corwin M Zigler; John D Spengler

doi:10.1038/s41370-024-00656-z

Chronic household air pollution and exposure patterns among Himalayan nomads

J Expo Sci Environ Epidemiol. 2024 Mar 5. doi: 10.1038/s41370-024-00656-z. Online ahead of print.

Authors

Catlin I Powers¹, Linyan Li^{2

3}, Majid Ezzati⁴, James P Butler^{1

5}, Corwin M Zigler⁶, John D Spengler¹

Affiliations

¹ Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
² School of Data Science, City University of Hong Kong, HKSAR, China. linyanli@cityu.edu.hk.
³ Department of Infectious Disease and Public Health, City University of Hong Kong, HKSAR, China. linyanli@cityu.edu.hk.
⁴ MRC Centre for Environment and Health, School of Public Health, Imperial College, London, UK.
⁵ Department of Medicine, Harvard Medical School, Boston, MA, USA.
⁶ Departments of Statistics and Data Sciences, University of Texas at Austin and Dell Medical School, Austin, TX, USA.

PMID: 38443463
DOI: 10.1038/s41370-024-00656-z

Abstract

Background: Household air pollution (HAP) is a major risk factor of non-communicable diseases, causing millions of premature deaths each year in developing nations. Populations living at high altitudes are particularly vulnerable to HAP and associated health outcomes.

Objectives: This study aims to explore the relationships between activity patterns, HAP, and an HAP biomarker among 100 Himalayan nomadic households during both cooking and heating-only periods.

Methods: Household CO was monitored in 100 rural homes in Qinghai, China, at 3500 m on the Himalayan Plateau among Himalayan nomads. Carboxyhemoglobin (COHb) was used as a biomarker to assess exposure among 100 male and 100 female heads of household. Linear mixed-effects models were used to explore the relationship between COHb and activity patterns.

Results: Cooking periods were associated with 7 times higher household CO concentrations compared with heating periods (94 ± 56 ppm and 13 ± 11 ppm, respectively). Over the three-day biomarker-monitoring period in each house, 99% of subjects had at least one COHb measurement exceeding the WHO safety level of 2%. Cooking was associated with a 32% increase in COHb (p < 0.001).

Impact statement: This study on household air pollution (HAP) in high-altitude regions provides important insights into the exposure patterns of nomadic households in Qinghai, China. The study found that cooking is the primary factor influencing acute carbon monoxide (CO) exposure among women, while heating alone is sufficient to elevate CO exposure above WHO guidelines. The results suggest that cooking-only interventions have the potential to reduce HAP exposure among women, but solutions for both cooking and heating may be required to reduce COHb to below WHO guidelines. This study's findings may inform future interventions for fuel and stove selection to reduce HAP and exposure among other populations.

Keywords: Biomarker; Carbon monoxide (CO); Himalayan nomads; Household air pollution (HAP); Personal exposure; Solid fuels.