Atmospheric Chemistry and Deposition

Pollutants released into the air can impact air quality, as well as terrestrial and aquatic ecosystems when the pollutants deposit to Earth. Effective targeting of air pollution controls depends on having good scientific understanding of which specific pollutant sources and regions are contributing to air and water quality issues. While much progress has been made in reducing releases of harmful air pollutants, many locations in the U.S. continue to experience problems associated with poor air quality. Air pollutants also damage crops and forests, degrade aquatic ecosystems, and contribute to climate change.

ARL evaluates and improves computer models used by NOAA’s National Weather Service to forecast the occurrence of ground-level ozone and fine particulate matter. These forecasts improve the ability of communities and individuals to respond to anticipated episodes of poor air quality by reducing pollutant emissions (e.g., limiting driving) and by taking personal protective measures (e.g., limiting outdoor exercise).

An example map of ground-level ozone concentrations predicted for the continental U.S. The NWS generates such maps twice daily using an ARL- developed modeling system.

ARL also conducts research on the exchange of pollutants between the air and the Earth’s surface. This improves scientific understanding of atmospheric chemistry and guides policies concerning air quality management and ecosystem health. ARL researchers focus on pollutants, such as mercury, reactive nitrogen, and sulfur compounds, which can have significant impact on the environment and—in the case of mercury—human health.

ARL’s activities include: a) developing and applying a specialized modeling system that tracks mercury emissions and links these emissions to atmospheric transport, transformation, and deposition; b) conducting long- term, intensive ambient air monitoring of mercury; c) conducting short- term, process-level field studies for mercury and reactive nitrogen compounds; and d) supporting long-term, research-grade monitoring of pollutants in precipitation.

Atmospheric-Composition-ARL-2021, (PDF icon, 600 KB)

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