MIT Atmospheric Chemistry: Understanding Atmospheric Composition and Its Impacts

MIT is a world-leader in atmospheric chemistry research and education. It is home to a number of research groups investigating diverse areas of atmospheric composition and its impacts. We currently span five different departments on campus: Civil and Environmental Engineering (CEE), Earth, Atmospheric and Planetary Sciences (EAPS), Engineering Systems Division (ESD), Aero-Astro and Chemistry, with over 50 researchers and students. You can learn more about our faculty, research, education programs and events on this webpage.

The MIT Earth System Initiative (ESI) is a contributing sponser of MIT Atmospheric Chemistry. There are 5 areas of research:

(1) EMISSIONS -- Global energy use has increased by almost 50% in the last two decades. The vast majority of energy conversion comes from the combustion of fossil fuels. Fuel combustion results in emissions of CO2, NOx, SOx, particulate matter, hydrocarbons and other species into the atmosphere, where they can be transported vast distances and interact with other chemicals. But it is not just power plants, cars, airplanes, and ships that emit pollution into the atmosphere – natural emissions are just as important, and just as big a scientific challenge. Vegetation, soil, wildfires and oceans all emit gases and particles into the atmosphere.

Much of atmospheric chemistry is about understanding how anthropogenic (human-related) emissions interact with natural emissions, perturb the chemical composition of the atmosphere, alter the climate, and affect human health. In order to do this we need to improve our understanding of emissions – the quantities of species emitted, their chemical and microphysical characteristics, and their sources. Moreover, assessing ways to mitigate emissions and understanding which emissions mitigation measures will have greatest environmental benefit is central to informing policy.

Research in this area at MIT includes the development of emissions inventory models, measuring and characterizing emissions, and using modeling techniques to infer emissions from indirect measurements.

(2) AIR QUALITY -- Poor air quality leads to the premature deaths of over 3 million people per year worldwide. Because of the rapid rate of urbanization in the developing world, this number is expected to rise dramatically over the next several decades. Air pollutants associated with negative health effects include ozone, fine particulate matter, and various other toxics. A large fraction of these pollutants are not emitted directly into the atmosphere, but rather are secondary in nature, formed in the atmosphere from chemical reactions of other compounds. Human exposure to these pollutants depends on a complex interplay of emissions, atmospheric reactivity, and transport; uncertainties in all of these limit our to formulate policies aimed at the effective prevention of air pollution.

Research at MIT involves both model and measurement approaches to better constrain sources, transformations, transport, and the effects of air pollutants. Specific focus areas include: chemical transformations, long range transport and human health.

(3) CLIMATE -- The temperature of the Earth is warmer now than at any period in at least the last several centuries. This warming is predominantly attributed to the addition of heat-trapping greenhouse gases (GHGs) to the atmosphere. Increases in sources of aerosol particles and their subsequent impact on radiation (termed ‘the direct effect’) and on cloud formation (termed ‘the indirect effect’) have offset some of, but not all, the GHG warming. Increases in chlorofluorocarbons (CFCs) have depleted the stratospheric ozone layer, and changes in the ozone layer can also affect climate of the lower atmosphere.

Atmospheric Chemistry at MIT tackles these issues using a combination of field studies, laboratory experiments, analysis of satellite and other data, and models from small to global scale. Our work considers more than gases and particles, and includes broader impacts on biogeochemistry and feedbacks on the larger Earth system. Specific focus areas include: chemistry-climate interactions, aerosols & clouds, biogeochemistry and stratospheric chemistry

(4) ECOSYSTEM IMPACTS -- Gases and particles transported in the atmosphere can deposit to ecosystems both near and far from their sources. Ozone can inhibit plant growth, impacting agricultural productivity and the food supply. Toxic chemicals such as mercury and persistent organic pollutants travel long distances through the air, bioaccumulate in food chains, and pose risks to ecosystems far from sources, especially in the Arctic. The atmosphere can also supply key nutrients associated with ecosystem productivity, including phosphorus and iron (components of atmospheric dust) and nitrogen, to remote regions. And finally, atmospheric chemistry can also influence the formation of precipitation, through aerosols that serve as cloud condensation nuclei. Altered patterns of precipitation can in turn lead to ecosystem changes.

Research at MIT related to the ecosystem impacts of atmospheric chemistry explores these issues through both observational and modeling studies. Specific focus areas include: Toxic effects of pollution transport and deposition, Nutrient supply to ecosystems through regional and global dispersion and Chemical influences on cloud formation.

(5) POLICY -- Managing the human impacts on the atmosphere is a substantial challenge for policy-makers at local, national, and international scales. In local areas, where concentrations of pollutants such as ozone and particulate matter exceed levels of concern for human health impacts, regulators set threshold levels and design policies to control emissions. However, these pollutants can interact and travel across borders, posing challenges for governance. Global atmospheric chemistry issues such as ozone depletion, climate change and toxic chemical transport are addressed by international treaties. Informing effective policies to address air pollution requires targeted science and engineering approaches.

At MIT, research related to atmospheric chemistry addresses these policy-relevant challenges. Related efforts at MIT include:
(*) Integrated assessment modeling links atmospheric chemistry with economics to assess coupled, system-level interactions
(*) Modeling policy scenarios to inform regulatory strategies
(*) Contributing to local, regional and global scientific assessments for policy, such as the Intergovernmental Panel on Climate Change