Wuhan, China — On January 20, 2020, Prof. Tangchun Wu at the Huazhong University of Science and Technology and Prof. Liming Li at the Peking University, published an original research entitled “Cooking fuels and risk of all-cause and cardiopulmonary mortality in urban China: a prospective cohort study”, in Lancet Global Health.

This study reconfirmed that the use of solid fuel for cooking was associated with higher risks of all-cause and cardiopulmonary mortality in urban areas, and was the first to reveal that the risk of mortality continued to decrease with time after cessation of solid fuel use. More importantly, use of effective ventilation was associated significantly with reduced risk of multi-cause mortality which caused by indoor air pollution that generated when combusted with solid fuels and clean fuels. Hence, the journal comments that this study provides important scientific evidence to promote the global environment and public health.

When combusted solid fuels (such as coal and biomass) indoors, it could generate a large amount of pollutants, for instance, hundreds to thousands of micrograms particular matter (PM2.5) per cubic meter; while clean fuels, such as electricity and natural gas, results PM2.5 ranging from tens to hundreds. Cooking is a requirement for human beings to ensure survival and pursue a better life. Along with the development of global economy and technology, cooking practice has gradually switched from solid fuels to clean fuels, with or without ventilation.

However, substantial emissions of pollutants which produced by the reaction of fuels, ingredients and oils at high temperatures, are not only the significant source of outdoor pollution but the primary source of indoor pollution. Therefore, the health hazard and its control tactic are the targeted focus of global health studies.

In 2018, the team had showed in JAMA that “In rural China, solid fuel use for cooking and heating was associated with higher risks of cardiovascular and all-cause mortality”, indicating that “the prevention measures that accelerate the transition to clean fuels and promote effective indoor ventilation”.

Nevertheless, many scientific issues remained unclear because of urban-rural disparity. For instance, the health hazard of urban residents when using solid fuels, the health benefit of transition from use of solid fuels to clean fuels, the health effect of cooking practice with ventilation facilities. Thus, the team conducted in-depth research to further exploration.

Based on the China Kadoorie Biobank study, the present study, with a mean of 9.8 years of follow-up, included 171677 participants from five urban areas, showed that, compared with persistent clean fuel users, persistent solid fuel users had significantly higher risks of all-cause mortality, cardiovascular mortality and respiratory mortality, with increased risks by 19%, 24% and 43%, respectively; compared with persistent solid fuel users, the users who switched from solid fuels to clean fuels had significantly decreased risks of all-cause and cardiovascular mortality. And the longer cessation time is, the greater risks of mortality reduced. The excess risk of mortality fell by more than 60% in 5 years after cessation of solid fuel use and continued to decrease afterwards, nearly to the level of clean fuel users in 10 years.

The point is, clean fuels are not in ideal condition for the incomplete combustion of fuels and stir-fry at high temperature can still produce smoke and contribute to air pollution. The latest finding showed that, compared with clean fuel users without ventilation, the users who used both clean fuels and effective ventilation had a decreased risk of all-cause mortality, cardiovascular mortality and respiratory mortality, with decreased risks by 22%, 24% and 34%, respectively.

The team leader pointed out that, using clean fuels and more effective ventilation for cooking practice is the direction for implementing concepts of clean-healthy kitchen. They suggested that both the policy makers and the public should accelerate the transition from solid fuels to clean fuels, and promote effective ventilation in cooking practice in order to achieve greater health benefits.

Chinese News Link: http://gwxy.tjmu.edu.cn/info/1067/3160.htm