image: The central panel displays the average spatial distribution of total chlorine emissions from 2001 to 2018, highlighting five high-density regions. The left and right panels illustrate the trends in chlorine emissions and the corresponding simulated ambient concentrations over the 18-year period.
Credit: ©Science China Press
An international research team led by the Hong Kong University of Science and Technology (HKUST), has uncovered the significant impacts of chlorine emissions from open biomass burning on air quality in Asia. The study offers valuable insights into the influence of these emissions on atmospheric chemistry and crucial information that can help mitigate regional air pollution.
Biomass burning is known as a major source of air pollutants and greenhouse gases, affecting air quality, radiative balance, and climate. While prior research has primarily focused on the releases of carbon and nitrogen species, chlorine emissions and their atmospheric impacts are not well understood. There is a lack of detailed quantitative information on chlorine emissions from biomass burning, particularly the high-resolution emission inventories, long-term trends, and associated atmospheric impacts on both regional and global scales.
To fill this gap, a team led by Prof. WANG Zhe, Associate Professor of HKUST’s Division of Environment and Sustainability has developed a comprehensive, long-term, high-resolution chlorine emission inventory for open biomass burning across Asia. Through extensive simulations and analyses of the data from 2001 to 2018, the study has indicated substantial chlorine emissions from biomass burning in key regions such as North China, Northern India, and Southeast Asia. The study also highlights distinct seasonal patterns and significant spatial and interannual variability, primarily driven by changes in agricultural practices.
The results demonstrate that biomass burning is not only a significant source of air pollutants, but also a key contributor to the production of atmospheric oxidants, affecting the atmospheric oxidation capacity directly and indirectly. This finding suggests that biomass burning emissions have a greater impact on atmospheric chemistry than previously acknowledged. With the expected increase in global biomass burning activities due to climate change, their role in shaping atmospheric composition could become even more pronounced.
"As efforts to reduce industrial emissions continue, the role of biomass burning in influencing atmospheric composition could become increasingly significant, especially as global warming expands fire-prone areas, potentially shifting toward more northern and colder regions," Prof. Wang said.
The study underscores the often-overlooked contribution of biomass burning to the global chlorine budget and its extensive effects on air quality and climate. The researchers emphasize that these emissions must be factored into future air quality management and climate change mitigation strategies. The role of biomass burning in chlorine emissions should be considered by policymakers when setting air quality targets to avoid underestimating the efforts needed to achieve them.
The findings of this study were recently published in the journal National Science Review (https://doi.org/10.1093/nsr/nwae285), lead authors Prof. WANG Zhe from HKUST, Dr. CHANG Di from Max Planck Institute for Chemistry and Prof. LI Qinyi from Environment Research Institute, Shandong University in collaboration with scientists across the United States, Spain, Germany, France, Argentina, Hong Kong and mainland China.
Journal
National Science Review