Organizations worldwide are increasingly taking steps to reduce their carbon footprints by adopting practices such as purchasing renewable energy and minimizing air travel. A recent study conducted by researchers at the Massachusetts Institute of Technology (MIT) highlights that while both actions can lower greenhouse gas emissions, their effects on air quality can vary significantly.
Using a sophisticated modeling approach, the researchers assessed the air quality impacts of different decarbonization strategies. They found that air travel contributes approximately three times more damage to air quality than similar investments in electricity from renewable sources. The study emphasizes the need to understand these differences as organizations strive to mitigate climate change while also benefiting public health.
Research Findings on Air Quality and Health
Exposure to major air pollutants, such as ground-level ozone and fine particulate matter, is linked to serious health issues, including cardiovascular and respiratory diseases, as well as premature death. The researchers, led by Noelle Selin, a professor in the MIT Institute for Data, Systems, and Society, illustrated that the air quality impacts vary by region. For instance, organizations in the northeastern United States find that while energy use affects local air quality, the consequences of air travel are felt on a global scale due to emissions released at higher altitudes.
“If we are trying to achieve net-zero emissions, the trajectory could have very different implications for air quality and health impacts,” Selin noted. “You can have more societal benefits if you figure out a smart way to structure your reductions.”
The study, published on March 15, 2024, in Environmental Research Letters, also includes contributions from lead author Yuang (Albert) Chen, along with other researchers from MIT and Imperial College of London.
Methodology and Economic Implications
Understanding the nuanced relationship between carbon dioxide reduction and air quality is complex. Traditionally, climate scientists have focused on broader national and regional policies, as these aggregate impacts are easier to model. In contrast, the MIT study delves into how individual organizational efforts to reduce CO2 emissions can influence air quality.
The researchers utilized data from two universities and one company in the greater Boston area to analyze whether actions that remove equivalent amounts of CO2 yield similar air quality benefits. “From a climate standpoint, CO2 has a global impact, but air quality impacts are driven by local co-pollutants,” Chen explained.
The team employed a systems-level approach, connecting multiple models and feeding in data related to energy consumption and flight emissions. This comprehensive methodology allowed them to assess local and regional air quality consequences systematically.
To quantify these effects, the researchers monetized air quality impacts, revealing that the damages linked to electricity purchases amount to an additional $88 per ton of CO2, while air travel inflicts a staggering $265 per ton. This stark contrast underscores how the air quality impact of emitted CO2 depends significantly on the source and method of emissions.
The analysis revealed unexpected findings regarding the geographical reach of aviation emissions. The team noted that emissions from air travel harm populations far removed from the source, with countries like India and China experiencing pronounced air quality challenges due to their pre-existing pollution levels.
Ultimately, the study suggests that organizations aiming for net-zero emissions must consider which CO2 reduction strategies produce the most immediate and significant health benefits.
Looking ahead, the researchers plan to explore the air quality impacts associated with train travel and other energy sources. This ongoing research could provide further insights into how organizations can effectively balance their sustainability goals with public health outcomes.
