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Air Quality

Cities in California's Central Valley rank among the most air-polluted in the United States. Key problems include particulates from agriculture and vehicular traffic, and ground level ozone. The sources change by seasons, tied to cycles of human activity in the valley, with obvious effects such as accentuating breathing difficulties, and more insidious illness such as valley fever, developmental problems and elevated rates of cancer.

Our studies are based in the Central Valley and worldwide. One example, considers the health economics of alternative modes of transport. The transportation sector is a major source of air pollution worldwide, yet little is known about the effects of transportation infrastructure on air quality.

UC Merced faculty researchers Yihsu Chen and Alexander Whalley have quantified the effects of one major type of transportation infrastructure — urban rail transit — on air quality using the sharp discontinuity in ridership on opening day of a new rail transit system in Taipei. They found that the opening of the Taipei Metro reduced air pollution from one key tailpipe pollutant, carbon monoxide, by 5 to 15 percent. Little evidence that the opening of the Metro affected ground level ozone pollution was found however.

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