A recent study from the Massachusetts Institute of Technology (MIT) highlights significant differences in air quality impacts stemming from corporate sustainability initiatives. Researchers investigated how actions like purchasing renewable energy and reducing air travel influence greenhouse gas emissions and broader air quality. Their findings indicate that despite similar reductions in carbon dioxide emissions, the societal benefits associated with each action can vary considerably.
Using a sophisticated modeling approach, the MIT team quantified the air quality impacts of these activities by analyzing data from three organizations located in the greater Boston area. The research reveals that air travel generates approximately three times more damage to air quality compared to comparable electricity purchases. This discrepancy is crucial, as exposure to major air pollutants—such as ground-level ozone and fine particulate matter—can lead to serious health issues, including cardiovascular and respiratory diseases.
According to Noelle Selin, a professor in the MIT Institute for Data, Systems, and Society and the Department of Earth, Atmospheric and Planetary Sciences, the study underscores the necessity for organizations to prioritize strategies that yield the most significant near-term health benefits. “If we are trying to get to net zero emissions, that trajectory could have very different implications for a lot of other things we care about, like air quality and health impacts,” Selin stated.
Understanding the Broader Impacts
The research reveals that air quality effects differ sharply across regions due to the varying scales at which each decarbonization action operates. For instance, in the northeastern United States, the impacts of energy use primarily affect local air quality, whereas the repercussions of air travel extend globally due to emissions released at higher altitudes. These emissions can be transported over vast distances by atmospheric winds, leading to detrimental effects on air quality in countries like India and China, which already face high levels of ground-level pollution.
The study’s lead author, Yuang (Albert) Chen, emphasized that air quality impacts depend significantly on the location of emissions. “From a climate standpoint, CO2 has a global impact because it mixes through the atmosphere, no matter where it is emitted. But air quality impacts are driven by co-pollutants that act locally,” Chen explained. The research utilized a systems-level approach, integrating various models and data on energy consumption and flight patterns to assess local and regional air quality.
Monetizing Air Quality Impacts
To provide a comprehensive comparison, the researchers monetized air quality impacts alongside climate impacts. Previous studies suggest that the monetized cost of damages caused by climate change due to CO2 emissions stands at about $170 per ton (in 2015 dollars). In contrast, the study found that air quality damages linked to electricity purchases amount to an additional $88 per ton of CO2, while damages from air travel reach $265 per ton. This stark difference highlights how the source and method of emissions can significantly affect public health and environmental quality.
One unexpected finding was the extensive reach of aviation emissions. Although emissions from flights occur far from the source, their impact is amplified by atmospheric conditions. “Not only were flights more damaging, but the pattern of damage, in terms of who is harmed by air pollution from that activity, is very different than who is harmed by energy systems,” Selin noted.
The research also delved into the air quality impacts of short-haul flights, revealing that regional flights have a more substantial local effect than longer domestic flights. This insight suggests that organizations aiming to enhance local air quality might benefit from re-evaluating their short-haul flight policies.
In conclusion, the outcomes of this study indicate that for organizations striving to reach net zero emissions while promoting sustainability, the order of CO2 reductions can significantly influence public health outcomes. The researchers plan to extend their investigation to assess the air quality impacts of train travel, seeking to determine whether replacing short-haul flights with rail journeys could yield additional benefits.
This important research was supported by funding from Biogen, Inc., the Italian Ministry for Environment, Land, and Sea, and the MIT Center for Sustainability Science and Strategy. The findings were published on March 2023 in Environmental Research Letters.
