Science & Technology

Estimating Atmospheric Deposition with CMAQ

Atmospheric deposition can be an important contribution to the total loading of nitrogen and sulfur to ecosystems. CMAQ model estimates can be fused with measured air concentration and wet deposition to reduce bias and develop grids and maps of total depo

Estimating Watershed Acidification using CMAQ

The Variable Infiltration Capacity (VIC) model was linked to WRF-CMAQ to provide hydrological information needed by the Model of Acidification of Groundwater In Catchment (MAGIC) to study stream water chemistry response to air quality regulations.

Browse CMAQ Applications

The CMAQ system has been used to address major environmental issues. Below are examples of how the CMAQ system provides information to help communities, states and countries determine the most effective strategies for reducing exposure to pollution.

Chesapeake Bay - CMAQ

Atmospheric deposition is a significant contributor to the total nitrogen loading to Chesapeake Bay. The CMAQ modeling system provides important information on the amount of atmospheric deposition for use in Total Maximum Daily Load analyses for different

Incremental Evaluation of CMAQv5.2

The impact on model predicted pollutant concentrations of the major changes in the CMAQv5.2 system compared to the last are tested one at a time. Evaluation results are summarized for ozone and PM2.5 based on simulations of January and July 2011.

Description of Changes in Climatic Indices in USA over 25 Years (1989 – 2013)

This report concentrates on the methodology and potential future uses for long-term climate factor trends, and trends of derived climatic factors and indices.

Frequently Asked Questions and Terms

Frequently Asked Questions of the EPA OIG including explanations of commonly used terms like audit, investigation and more.

Action Update: EPA Identifies the Spilled Chemical Compound in Garnett, Kansas

U.S. Environmental Protection Agency (EPA) has identified the chemical compound spilled in Garnett, Kansas, on Dec. 31, 2025.

Release Date: January 30, 2026

Addressing Nonpoint Source Pollution through EPA’s National Nonpoint Source Program Webcast

Nonpoint source pollution webcast

Watershed Academy Webcast: EPA Releases First Ever National Wetland Condition Assessment

Presentation from June 16, 2016 webcast.

Slide Deck: State Legislation on Ocean & Coastal Acidification Webinar

State Legislation on Ocean & Coastal Acidification Slide Deck

How's My Waterway January 2022 Webcast

How’s My Waterway has added several new features over the past year that will be featured in this webcast.

Using EPA’s EnviroAtlas and Recovery Potential Screening Tools to Support Sound Decision Making

Webcast, Using EPA’s EnviroAtlas and Recovery Potential Screening Tools to Support Sound Decision Making

Building Resilience in Partnership with Vulnerable Communities

This webinar will look at the factors that contribute to vulnerability and provide examples of how EPA and its partner programs have effectively worked to help build resilience with vulnerable communities.

Lead (Pb) Overview and Data Mapping Webinar Archive

This EPA Tools & Resources webinar provides an overview of the Administration priorities for lead (Pb) and a detailed look at a multimedia data mapping approach available for states and partners to use to identify potential lead exposures.

References

This is a list of references.

Hemispheric Scale Applications

Air quality is a global issue since air pollutants can be transported between countries and even continents. CMAQ can be used over a domain covering the entire northern hemisphere, providing information on interactions occurring at various spatial scales