Harvard University homepage
HARVARD.EDU

Atmospheric Chemistry Modeling Group – Harvard University

ACMG Mickley Subgroup

Group Leaders Daniel J. Jacob and Loretta J. Mickley

Research

Note for Editors:
Each publication link (e.g., “PDF,” “Supplement” etc.) includes a publication title wrapped in <code> tags, such as <code>publicationTitle</code>. While the style sheet hides this content visually, it remains accessible to assistive technologies, ensuring publication titles are repeated to describe each link (see accessibility guidelines for descriptive links).The second <code> element (e.g., “PDF,” “Supplement”) is visible and styled as a button.
To add <code> tags to publication titles, after selecting the publication title within the link, select the “inline code” text format.
For a demonstration and assistance, contact Vittorio at vbucchieri@seas.harvard.edu.

The goal of our research is to understand how short-lived chemical species in the atmosphere, including tropospheric ozone and aerosol, interact with climate on global and regional scales. We use global models of climate and atmospheric chemistry together with observations from the recent and distant past. We also build statistical models to quantify observed relationships between meteorological variables and air quality. Much of our current research is focused on the air quality impacts of fire activity.

Current areas of research

Wildfires, agricultural fires, and consequences for air quality

Background

Wildfires and agricultural fires can have large impacts on air quality and atmospheric composition. For example, fires in Indonesia, used routinely to clear land for crops, can severely degrade air quality in megacities downwind. Through their effects on fires, both climate change and land-use decisions can have unexpected consequences for air quality. See also the following sections, Effects of changing air quality on human health and Impacts of aerosol trends on regional climate.

Key questions

  • How will climate change affect wildfire frequency and the resulting smoke burden?
  • What are the impacts of wildfires and agricultural fires on regional air quality?
  • What is the utility of prescribed fires to minimize the smoke risk from large wildfires?

Selected references

Press

BBC, National Geographic, New Scientist, New York Times, The Guardian (twice), Wall Street Journal, Washington Post.

Support

EPA, Health Effects Institute, NASA, NOAA, Rockefeller Foundation

Effects of changing air quality on human health

Background

Given recent and sometimes dramatic trends in emissions, climate change, and fire frequency, the atmosphere is in flux. We collaborate with biostatisticians and epidemiologists to probe the health consequences of changing air quality in the United States and elsewhere. See also the section on Wildfires and agricultural fires above.

Key questions

  • How will the frequency of “smoke waves” change in the western United States in a warming climate, and what are the consequences for acute health issues?
  • Will the combination of increasing heatwaves and changing pollution in future decades adversely affect human health?
  • How does pollution from fossil fuel combustion affect human health worldwide?

Selected references

Press

Climate Central, NASA Image of the Day.

Support

EPA, Health Effects Institute, NASA, NIH, NOAA, Rockefeller Foundation, Wallace Global Fund.

Air quality response to changing meteorology and climate

Background

Weather is a major factor affecting surface air quality, and it follows that climate change could impose a significant “climate penalty” on pollution control strategies. In our ongoing Global Change and Air Pollution (GCAP) project, we investigate the impact of climate variables on air quality in the present-day and near future.

Key questions

  • What are the dominant meteorological drivers of surface ozone and particulate matter?
  • Should policymakers take into account a “climate penalty” on U.S. air quality?
  • Will future climate change exacerbate air quality in China?
  • What governs dust events in the western United States and how will climate change affect these episodes?

Selected references

Press

Capital Public Radio, NBC, The Nation.

Support

EPA, NASA, NIH.

Impacts of aerosol trends on regional climate

Background

Aerosols influence regional climate through their interactions with incoming solar radiation and with clouds. Aerosols are also known as particulate matter and represent a major component of air pollution. In recent decades U.S. enviromental policies have led to large cuts in aerosol sources, but the consequences for regional climate are not clear. At the same time, aerosol loading in Asia has increased dramatically as rapid industrialization takes place there. The climate impacts of these disparate trends in anthropogenic emissions for remote regions such as the Arctic are unknown.

Key questions

  • Can we explain the observed U.S. “warming hole” of the 1980s with trends in aerosol sources?
  • Do trends in aerosols influence regional hydrology, including drought risk?
  • What role does changing aerosol have in the observed rapid warming over the Arctic?
  • What are the climate consequences of increasing aerosol over China?

Selected references

Press

NASA Image of the Day, National Geographic, New York Times.

Support

EPA, EPRI, NASA, NSF.

Chemistry-climate interactions in past climates

Background

In a series of projects, ICE age Climate And Proxies (ICECAP), we investigate the different influences on the atmospheric oxidative capacity over long timescales. We also examine the impacts of abrupt or gradual climate change on wildfire activity. These studies shed light on the lifetime of key greenhouse gases in the present-day and on the potential consequences of future climate change.

Key questions

  • What controls oxidant levels on long timescales?
  • How has abrupt or gradual climate change in the past affected wildfire activity?
  • How have trends in fire activity changed over long timescales and what are the implications for aerosol radiative forcing?

Selected references

Press

Xinhua, Science Daily.

Support

NSF, NASA

New insights into surface air quality

Background

As the observational record in the modern era lengthens, we can learn more about the mechanisms and sources of key atmospheric species and their changes over time. We can diagnose the impacts of policy measures, including unintended consequences, and detect shifts in pollution sources. For research on the meteorological influences on air quality, go to Climate impacts above.

Selected references

HARVARD JOHN A. PAULSON
SCHOOL OF ENGINEERING
AND APPLIED SCIENCES

HARVARD UNIVERSITY
DEPARTMENT OF EARTH AND
PLANETARY SCIENCES

HARVARD UNIVERSITY
CENTER FOR THE
ENVIRONMENT

JOINT LABORATORY FOR AIR
QUALITY AND CLIMATE
(JLAQC)