CAMx (Comprehensive Air Quality Model with Extensions) is a state-of-the-science photochemical grid model used to simulate air pollution, including ozone, particulate matter, mercury, and other air toxics, across scales from neighborhoods to continents. It’s widely used by government agencies, industry, and researchers for regulatory analyses, source attribution, and air quality studies. As an open-source, flexible, and computationally efficient tool, CAMx has been continuously developed for over 25 years.