Cleanup of hazardous waste sites can involve significant consumption of gasoline, diesel, or other fuels by mobile and stationary sources. Minimizing emission of air pollutants such as greenhouse gases (GHGs) and particulate matter (PM) resulting from cleanup activities, including those needing fossil or alternative fuel, is a core element of green remediation strategies. Efforts to reduce these emissions during site investigation, remedial or corrective actions, and long-term operation and maintenance (O&M) must meet Clean Air Act (CAA) requirements and state air quality standards as well as requirements of federal and state cleanup programs. Deployment of green remediation BMPs can help reduce negative impacts of cleanup activities on public health and the environment. The CAA currently specifies nitrogen dioxide (NO2), ozone, lead, carbon monoxide (CO), sulfur dioxide (SO2), and PM as the nations criteria air pollutants. EPAs air quality criteria and national ambient air quality standards (NAAQS) for criteria pollutants must be met in all state implementation plans. The Agency has studied impacts of six key GHGs in the atmosphere: carbon dioxide (CO2), methane, nitrous oxide (N2O), hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride. Studies found that emissions of these GHGs from new motor vehicles and new motor vehicle engines contribute to GHG pollution threatening public health and welfare.