SW-NCA-color-FINALweb

318 assessment of climate change in the southwest united statesFigure 15.3 Incidence of selected diseases in the Southwest as a percent of total for theUnited States.The proportion of the total cases in the United States of West Nile virus, valley fever,plague, and Hanta pulmonary syndrome reported annually from the Southwest to the CDC showsconsistency from year to year. Data from cases reported to the CDC.Emissions and air pollutionRising temperature will accelerate atmospheric chemical reactions, tending to increaseconcentrations of ozone and possibly PM2.5 (Steiner et al. 2006; Jacobson 2008; Kleeman2008; Mahmud et al. 2008; Millstein and Harley 2009). However, other meteorologicalcharacteristics, such as relative humidity, wind speed, and mixing height 3 also interactwith temperature and influence pollutant concentrations (Steiner et al. 2006; Jacobson2008; Kleeman 2008; Mahmud et al. 2008; Millstein and Harley 2009). Changes in ozoneand PM2.5 levels are unlikely to be uniform across an air basin. There remain many uncertaintiesin our current understanding of the influence of meteorological parameterson air quality. In addition, current strategies for modeling ozone cannot yet factor in thereduction of air pollution that is expected from regulations and control strategies thatwill be adopted to meet NAAQS attainment requirements. Thus, current knowledge isinadequate to project future health impacts. However, without implementation of newair-pollution-control strategies, the concentrations of these pollutants could increasewith climate change, and consequently contribute to increased air pollution-relatedhealth effects (Knowlton et al. 2004; Peng et al. 2011).Increases in extreme eventsIncreased climate extremes (heat waves and winter cold) and their direct effects, alongwith indirect effects related to vector populations, are expected to have an overall negativeeffect on human health (McMichael 2001). In particular, future heat waves are