Scientists detect that firewood is the main pollutant in Santiago
September 26, 2022
Firewood: The Leading Cause of Air Pollution in Santiago Despite Its Prohibition
Although firewood is prohibited in the Metropolitan Region, it remains the main source of residential air pollution in Santiago, according to the first National Air Quality Inventory, developed by researchers from Universidad de Chile, Pontificia Universidad Católica, Universidad Austral, Universidad Técnica Federico Santa María, and research centers such as the Center for Climate Science and Resilience (CR)².
The study, which analyzed emissions from residential, transportation, industrial, energy, and mining sectors between 2015 and 2017, measured pollution sources down to a one-square-kilometer resolution, providing a high-definition view of pollution distribution.
Published in the journal “Earth System Science Data” (available here), the study evaluated pollutants such as fine particulate matter (PM2.5), coarse particulate matter (PM10), carbon monoxide (CO), volatile organic compounds (VOCs), and black carbon.
According to Dr. Nicolás Huneeus, an atmospheric sciences specialist and professor at Universidad de Chile’s Department of Geophysics, PM2.5 is the most critical pollutant for human health:
“Due to its small size, PM2.5 can penetrate deep into the respiratory system. Meanwhile, for agriculture, ozone and carbon monoxide are more significant, as they affect climate patterns.”
Residential Firewood Use: The Primary Pollutant in Chile
Nationally, the residential sector is responsible for over 90% of PM2.5 emissions. In the Metropolitan Region, where 40% of Chile’s population lives, 81% of air pollution comes from household combustion sources, primarily firewood used for heating, cooking, and water heating. In contrast, transportation accounts for only 15% of emissions, according to Nicolás Alamos, lead author of the study and researcher at (CR)².
The study also highlighted regional differences in pollution sources:
- Northern Chile: Energy, transportation, and residential activities generate the most pollution.
- Southern Chile: The residential sector dominates pollution levels, particularly due to firewood use for heating.
New Heating Alternatives Needed
“There are no official statistics on firewood consumption because it is not officially classified as a fuel, despite its widespread use for heating homes,” said Dr. Huneeus.
“It’s surprising that residential firewood emissions in Santiago are so significant. While you won’t see people burning firewood in downtown Santiago, it is common in the city’s outskirts and peripheral areas.”
Raúl O’Ryan, an environmental specialist at the Center for Energy Transition (CENTRA) at Universidad Adolfo Ibáñez, explained that PM2.5 concentrations peak in winter due to lower temperatures and weaker winds, which trap pollution in the air.
“In summer, stronger winds help disperse pollution. However, it is crucial to model these data to determine the most affected areas,” he suggested.
For Dr. Katherine Brintrup, director of the School of Energy and Sustainability at Universidad San Sebastián, the study’s findings are unexpected because it was previously unclear where pollution originated. Additionally, firewood use is legally restricted in Santiago.
“It’s concerning that firewood is the main source of pollution, and that transportation ranks second—previously, we assumed the opposite,” she noted.
Implications for Public Policy
This study provides valuable insights for designing better air pollution control policies, including:
- Targeted intervention at critical pollution hotspots.
- Promoting cleaner heating alternatives.
- Addressing economic barriers preventing the switch to cleaner fuels.
“If people are using less clean energy, it’s because firewood is cheaper,” said Dr. Brintrup.
“Vulnerable communities tend to use any available firewood, regardless of its pollution impact. With these data, we can pinpoint the most critical areas and develop strategic municipal policies to address them.”
Challenges in Replacing Firewood
O’Ryan acknowledged that competing with firewood is difficult, particularly in southern Chile, where it remains the dominant heating source.
“We need to improve the quality of firewood and the efficiency of heating equipment. Ideally, we should encourage a technology shift toward cleaner alternatives like pellets.”
Dr. Huneeus hopes that the study will inform policymakers, but he also believes making air quality data accessible to the public could drive awareness and behavior change.
“In Chile, people don’t often check air pollution levels in their area, but they should. Knowing if you live in a high-pollution zone should factor into housing and lifestyle decisions.”
Source: Las Últimas Noticias