Analyzing Impacts to Air Quality at the Program Level
This paper describes the assessment of potential adverse effects on air quality pursuant to the environmental impact review requirements of the California Environmental Quality Act (CEQA). In addition to a general discussion of procedures and requirements of CEQA that pertain to air quality, this paper also includes specific screening approaches, methodologies, and techniques for calculating emissions at the planning and design level along with criteria for determining whether a project would result in a significant impact. This includes the incorporation of traffic studies and modeling to quantify mass emission increases in ozone precursor and particulate matter emissions, indirect source review, and the application of dispersion modeling for the assessment of human health risk from exposure to hazardous air pollutants, such as diesel exhaust. This paper discusses the relationship between air quality and land use development, as it pertains to the generation of vehicle trips and associated emissions as well as the exposure of sensitive receptors to stationary- and mobile-sources of toxic air contaminants. The implementation of mitigation measures, as required by CEQA, is discussed. The effectiveness and feasibility of various operational and design-level mitigation measures are also considered in this paper and examples provided from recently proposed development projects. This discussion focuses on measures that incorporate smart-growth concepts into project design and the quantifiable emission reductions they achieve.