Climate Science and Policy

The most popular method for reducing traffic related air pollution in Europe is to implement a Low Emission Zone (LEZ). The objective of this type of policy is to eventually phase out the operation of exhaust emitting vehicles in densely populated city centers. Reducing ambient air pollution is important because the rates of mortality associated with air pollution constitute a public health crisis. The LEZ in Paris, France was first implemented in 2015 and is currently in Phase 1 of its roll out schedule. The aim of this study was to determine the most equitable method for implementing Phase 2 of the Paris LEZ. To date, there is a significant lack of evidence that determines the impact that LEZs have on equity.

 The methods for this project involved extending the results of the Host et al. study which evaluated four hypothetical scenarios for Phase 2. Parameters evaluated by Host et al. were air pollution and expected health benefits. In order to determine the expected health benefits, a health impact assessment (HIA) was conducted. Evaluating Host et al.'s results in terms of equity meant utilizing the methods of a study by Kihal-Talantikite et al. This involved stratifying the census blocks of the Paris inner city region and the Metropolis of Greater Paris region into three socioeconomic groups based on Fdep scores. Next, by conducting a new health impact assessment, the expected health benefits were evaluated using three separate relative risk values for each socioeconomic group. The pollutants considered for this study were NO2 and PM2.5, and the health benefits evaluated were childhood asthma in children under 17 years old and all-cause premature death in adults over 30 years old. The results of this study determined that the scenario with the largest LEZ perimeter and the most stringent vehicle standards produced the highest number of cases avoided and the most equitable distribution of health benefits, especially for prevented cases of childhood asthma. If these methods to incorporate equity into HIAs continue to be developed and used for future LEZs and other air pollution policies, it will be easier and more effective to reduce the burden of ambient air pollution on society and the environment.