Recent work in the Heald group has investigated the processes controlling the emissions, export and transport of dust from North Africa more than 3000 km across the Atlantic. The fraction of dust that is ultimately deposited over South America is a critical source of phosphorous to the Amazon, supporting the rainforest’s growth and productivity.
Learn more about the Heald group’s research here.
Work in the Selin group uses global modeling tools to explore how persistent organic pollutants (POPs) reach the Arctic. Once there, they pose risks to Arctic ecosystems and populations. During their transport, POPs can undergo chemical reactions, partitioning to atmospheric particles, and wet and dry deposition. Models are tools that help us constrain these processes, and identify the sources of Arctic pollution.
While the Antarctic ozone hole represents the most spectacular example of ozone depletion, losses of ozone have occurred in other regions of the world, raising questions about their origins, magnitude, and influences on climate. The Solomon group’s foci include detailed examination of changes in ozone in the tropical and mid-latitude lower stratosphere, their radiative effects, and the range of uncertainties in estimates of how much ozone has changed in these regions. A recent project showed that tropical lower stratospheric ozone losses could be larger than generally thought, with a potential for important effects on climate.
Learn more about the Solomon group’s research here.
Atmospheric composition is evolving on timescales from seconds to decades in response to changes in emissions and climate. In the Heald group, research is focused on understanding the critical role that land use change and biosphere-atmosphere interactions can also play in controlling future atmospheric composition. We use state of the art global climate models to explore these coupled processes. For example, a recent project investigated how the bark beetle infestation of the last decade has impacted natural emissions and air quality in Western North America.
Learn more about the Heald group’s research here.
By combining field collections of the ice crystals with laboratory measurements the Cziczo group has been able to show that lead-containing particles act as highly effective cloud formation agents. Although anthropogenic lead has decreased since the heyday of leaded gas in the 1970’s and 80’s the vast majority of atmospheric lead still comes from human activities. Understanding future emissions will be critical to understanding possible effects on climate.
Learn more about the Cziczo group’s research here.
Breathing air with high concentrations of certain pollutants, such as ozone and fine particulate matter, can damage human health. Exposure to these pollutants can affect the cardiovascular and respiratory system, causing illnesses such as asthma and premature mortalities. Research in the Selin group links atmospheric chemistry modeling to impacts analysis, using integrated assessment models, to quantify the human health and economic impacts of air pollutants, and address the potential benefits of policies to control pollution. Research in the Barrett group assesses the human health impacts of aviation emissions, on regional to global scales.
Pollutants can travel across ocean basins to affect air quality far down-wind of emission sources. The Heald group makes use of satellite and aircraft observations to study the chemical transformations and impacts resulting from this kind of long range transport.
Learn more about the Heald group’s research here.
The oxidation of organic compounds in the atmosphere leads to the formation of ozone, fine particulate matter, and hazardous air pollutants. Despite their importance, these oxidation processes are generally poorly understood due to their high chemical complexity. The Kroll group is therefore developing new ways to probe organic oxidation mechanisms in the laboratory. Examples include “aging” organics by exposing them to high concentrations of oxidants, zeroing in on individual reaction steps by generating organic radicals in the absence of any oxidants at all, and limiting oxidation to Individual phases.
Learn more about the Kroll group’s research here.
In recent decades air quality has improved in many regions of the world with the reduction of sulfur emissions from power plants. However, particulate matter from nitrogen sources is on the rise. One of the factors contributing to this is the source of ammonia from the agricultural sector. The Heald group has been using new satellite observations to try to investigate these sources, and field measurements to investigate the contribution of ammonia in particulate matter formation in regions such as California.
Organic aerosol an important role in air quality and climate issues, however the sources of these particles and their transformations in the atmosphere are not well understood. Research in Jesse’s Kroll lab focuses on investigating some of the fundamental chemical aging processes for organic aerosol. At the same time, Colette Heald’s group has focused on trying to characterize the contribution of organic aerosol to the global aerosol budget using satellite and aircraft observations. Both groups are interested in developing descriptions of the evolution of organic aerosol in the atmosphere that can be used in models.
Learn more about the Kroll group’s research here.
Learn more about the Heald group’s research here.
