GSA Spotlight: Tina Liu

GSA Spotlight: Tina Liu The Impacts of Forest Fires on Air Quality and Public Health in India

Tianjia (Tina) Liu, who joined the Mittal Institute as a Graduate Student Associate for academic year 2021-2022, is a Ph.D. Candidate in the Department of Earth and Planetary Sciences at Harvard. Her research focuses on using satellite data and atmospheric modeling to quantify the impacts of fires on air quality and public health in India, Indonesia, and globally.

The Mittal Institute interviewed Tina about her interdisciplinary research. Mittal Institute: What are your academic interests, and how or why did you first become interested in your current research topics?

Tina Liu: I first became interested in research on fires and air quality during my junior year at Columbia University, when I applied for an undergraduate research assistantship at the Earth Institute. For the project, I used satellite fire data and air quality measurements to determine if agricultural fires had any large impacts on air quality in major Indian cities, such as Delhi and Bangalore. During my undergraduate years, I also explored other research topics, such as paleoclimate and oceanography, at the Lamont-Doherty Earth Observatory and Woods Hole Oceanographic Institution, but most of the other projects were not as relevant in today’s world and required extensive lab work.

Mittal Institute: When focusing on forest fires and climate change, why is it that your research is centered on India and Indonesia? Likewise, can you explain the linkage between wildfires and climate change?

Tina Liu: While my India and Indonesia work focuses on how and why humans use fire and the consequences for air quality and public health, climate

change could certainly be a factor in exacerbating the dry and hot conditions needed for fires to grow out of control or influencing farmers’ decisions to burn crop residues. In north India, agricultural fires are set by farmers to quickly clear their fields of crop residues before planting the next crop. To stem groundwater depletion, state policies delayed rice planting dates closer to the summer monsoon onset. However, this inadvertently worsens air pollution issues during the post-monsoon as more farmers set crop residues on fire in order to save time and cope with the shorter turnaround time between rice harvests and wheat planting.

Climate change may have played a role in accelerating groundwater depletion in north India by modulating monsoon onset and precipitation and increasing evaporation rates. In Indonesia, forest fires are tied to deforestation, agriculture, and management of oil palm, timber, and logging plantations. During drought years, such as 2006, 2015, and 2019, fires often burn out of control. In particular, some fires occur in carbon-rich peatlands; when the water table is low, peat dries out, and fires can burn for weeks to months. If climate change plays and/or continues to play a role in exacerbating drought conditions in Indonesia, the fire season could become even more severe in future years.

Mittal Institute: The public health impacts of wildfires are obviously profound. Can you talk a bit about that, and do you interface with anyone from Harvard to look at the public health data?

Tina Liu: When we link fires to public health, we look at concentrations of fine particulate matter, or tiny aerosols, that fires emit. Because these aerosols are smaller in diameter than that of your hair, they can get lodged deep into the lungs and can even enter the bloodstream, causing cardiovascular and respiratory diseases and worsening pre-existing conditions. For our Indonesia work, we collaborated with Dr. Joel Schwartz, Dr. Samuel Myers, and Dr. Jonathan Buonocore at T.H. Chan School of Public Health to quantify the number of premature deaths due to the 2015 fire season.

In our study, we estimated 100,000 premature deaths across Indonesia, Singapore, and Malaysia throughout the year following the fires. We used robust relationships between fine particulate matter and mortality that are generalized from many epidemiological studies. In more recent work, we collaborated with Dr. Francesca Dominici and her group to quantify links between wildfires and COVID-19 in the western US.