Trans-generational changes and rural-urban inequality in household fuel use and cookstove ventilation in China: A multi-region study of 0.5 million adults

Background: Disease burden estimates related to household air pollution (HAP) relied on cross-sectional data on cooking fuel, overlooking other important sources (e.g. heating) and temporal-regional variations of exposure in geographically diverse settings. We aimed to examine the trends and variations of for cooking and heating fuel use and ventilation in 500,000 adults recruited from 10 diverse localities of China. Methods: At baseline (2004-08) and two subsequent resurveys (2008-14), participants of China Kadoorie Biobank, aged 30-79, reported their past and current fuel use for cooking and heating and the availability of cookstove ventilation. These were compared across regions, time periods, birth cohorts, and socio-demographic factors. Results: During 1968-2014, the proportion of self-reported solid fuel use for cooking or heating decreased by two-thirds (from 84% to 27%), whereas those having complete kitchen ventilation tripled (from 19% to 66%). By 2014, despite a continuing downward trend, many in rural areas still used solid fuels for cooking (48%) and heating (72%), often without adequate ventilation (51%), in contrast to urban residents (all < 5%). The large urban-rural inequalities in solid fuel use persisted across multiple generations and also varied by socioeconomic status, especially in rural areas. Conclusions: Despite marked progress in fuel modernization in the last 50 years, substantial rural-urban inequalities remain in the study population, especially those who were older or of lower socioeconomic status. Uptake of cleaner heating fuel and ventilation has been slow. More proactive and targeted strategies are needed to expedite universal access to clean energy for both cooking and heating.