Natural (Non-Anthropogenic) Source Methodologies Contact Email aqpsd@arb.ca.gov Phone (916) 322-5350 Area Source CategoriesGeogenic SourcesAgencyPetroleum Seeps - Oil & GasCARBSoil NOx and NH3CARBWildfiresAgencyWildfires - All CategoriesCARBWildland Fire Use (WFU) FiresCARB