摘要：Objectives. As part of a community-based participatory research effort, we estimated the preventable burden of childhood asthma associated with air pollution in the southern California communities of Long Beach and Riverside. Methods. We calculated attributable fractions for 2 air pollution reduction scenarios to include assessment of the newly recognized health effects associated with residential proximity to major roads and impact from ship emissions. Results. Approximately 1600 (9%) of all childhood asthma cases in Long Beach and 690 (6%) in Riverside were attributed to traffic proximity. Ship emissions accounted for 1400 (21%) bronchitis episodes and, in more modest proportions, health care visits for asthma. Considerably greater reductions in asthma morbidity could be obtained by reducing nitrogen dioxide and ozone concentrations to levels found in clean coastal communities. Conclusions. Both Long Beach and Riverside have heavy automobile traffic corridors as well as truck traffic and regional pollution originating in the Los Angeles–Long Beach port complex, the largest in the United States. Community-based quantitative risk analyses can improve our understanding of health problems and help promote public health in transportation planning. Community groups in southern California have been increasingly concerned about the health effects of exposure to some of the highest levels of urban air pollution in the United States. Statewide risk assessments have concluded that substantial cardiovascular and respiratory disease mortality and large numbers of cardiorespiratory emergency visits and hospitalizations, asthma exacerbations, and chronic bronchitis are attributable to high levels of particulate matter and ozone (O3). 1 , 2 However, only rarely has this methodology been applied to smaller geographical scales taking into account local air pollution conditions and sources. Information about the local health burden of air pollution would be useful for evaluating proposals to expand port facilities and transportation infrastructure in the Los Angeles air basin. Expansion at the adjacent ports of Long Beach and Los Angeles, the largest port complex in the country, has resulted in an increasing contribution to the region's air pollution. Air emissions from ships, yard equipment, railroads, and trucks account for about 10% of the daily particulate matter, 24% of nitrogen oxides, and 73% of the daily sulfur oxides in the entire Los Angeles air basin. 3 Ship emissions alone contribute substantially to coastal and inland air pollution. 4 A doubling or tripling of cargo through the region by 2025 is predicted, 5 , 6 threatening decades of progress in reducing levels of air pollution. As part of a community-based participatory research effort to provide information that could help communities evaluate plans for port expansion, we estimated the burden of childhood asthma attributable to air pollution in the southern California cities of Long Beach (population 136 000) and Riverside (population 76 500). Residents from these communities have challenged port expansion on the basis of concerns about the health effects of ship emissions and of traffic proximity, which have not been well characterized in prior health risk assessments. 7 , 8 Novel features of our effort include an assessment of the impact of residential proximity to major roads on the burden of childhood asthma. Recent research suggests that traffic proximity is not only associated with severity and persistence of asthma in children but also with increased risk of asthma onset. 9 – 11 In addition, we have evaluated the burden of childhood asthma attributable to ship emissions as an example of a specific source of port-related pollution effects.
