Evaluation of the public health impacts of traffic congestion: a health risk assessment

Background: Traffic congestion is a significant issue in urban areas in the United States and around the world. Previous analyses have estimated the economic costs of congestion, related to fuel and time wasted, but few have quantified the public health impacts or determined how these impacts compare in magnitude to the economic costs. Moreover, the relative magnitudes of economic and public health impacts of congestion would be expected to vary significantly across urban areas, as a function of road infrastructure, population density, and atmospheric conditions influencing pollutant formation, but this variability has not been explored. Methods: In this study, we evaluate the public health impacts of ambient exposures to fine particulate matter (PM2.5) concentrations associated with a business-as-usual scenario of predicted traffic congestion. We evaluate 83 individual urban areas using traffic demand models to estimate the degree of congestion in each area from 2000 to 2030. We link traffic volume and speed data with the MOBILE6 model to characterize emissions of PM2.5 and particle precursors attributable to congestion, and we use a source-receptor matrix to evaluate the impact of these emissions on ambient PM2.5 concentrations. Marginal concentration changes are related to a concentration-response function for mortality, with a value of statistical life approach used to monetize the impacts. Results: We estimate that the monetized value of PM2.5-related mortality attributable to congestion in these 83 cities in 2000 was approximately $31 billion (2007 dollars), as compared with a value of time and fuel wasted of$60 billion. In future years, the economic impacts grow (to over $100 billion in 2030) while the public health impacts decrease to$13 billion in 2020 before increasing to $17 billion in 2030, given increasing population and congestion but lower emissions per vehicle. Across cities and years, the public health impacts range from more than an order of magnitude less to in excess of the economic impacts. Conclusions: Our analyses indicate that the public health impacts of congestion may be significant enough in magnitude, at least in some urban areas, to be considered in future evaluations of the benefits of policies to mitigate congestion

Environmental effects of ozone depletion and its interactions with climate change: Progress report, 2004

The measures needed for the protection of the layer are decided regularly by the Parties to the Montreal Protocol, now consisting of 188 countries. The Parties are advised on knowledge relevant to this task by three panels of experts: the Scientific, Environmental Effects, and Technology and Economic Assessment Panels. These panels produce an assessment every four years. The Environmental Effects Assessments are also published in the scientific literature; the latest report was published as a series of papers in Photochemical & Photobiolog-ical Sciences, 2003, 2, 1–72. In the intermediate years, the panels keep the Parties informed on new developments. The following Progress Report is the 2004 update by the Environmental Effects Assessment Panel and follows that for 2003 (Photochemical & Photobiological Sciences, 2004, 3, 1–5). Since the first assessments in 1989, the complexity of the linkages between ozone depletion (Fig. 1), UV-B radiation and climate change has become more apparent. This makes it even clearer than before that we are dealing with long-term ozone developments, which can be complicated by large year to year variability. Originally published by the United Nations Environment Programme (UNEP) as Environmental Effects of Ozone Depletion and its Interactions with Climate Change: Progress Report 2004