Implementation of various hypothetical low emission zone scenarios in Greater Paris: Assessment of fine-scale reduction in exposure and expected health benefits.

OBJECTIVES: Literature assessing the effects of policies aimed at reducing traffic-related air pollution is scarce. The aims of this study were to evaluate the expected impacts, in terms of air quality and health effects, of various hypothetical low-emission zone (LEZ) scenarios in Greater Paris for a planned intervention in 2018/2019 which combine two different perimeters and two levels of vehicles ban, and to assess those impacts according to the socioeconomic status (SES) of the population.

METHODS: We evaluated the effects of four hypothetical LEZ scenarios on various stages of the full-chain model, more specifically, road traffic modelling (traffic flow, type of vehicles and related number of kilometers driven), emissions, fine scale PM2.5 and NO2 concentrations, related resident population exposure, and health effects. We computed the overall benefits of expected air pollution improvements in terms of preventable deaths and a decrease in new cases of the following three major chronic diseases: ischemic heart diseases in adults, asthma in children and low weight in full-term newborns.

RESULTS: The most stringent LEZ scenario would lower the maximum level of exposure from 55 μg/m3 to 42 μg/m3 in Paris. In one year, this scenario would help prevent: 340 deaths (-0.6%) representing 114,300 life years gained, 170 low-weight full-term births (-4.9%), 130 new cases of ischemic heart disease (IHD) (-1.8%) and 2930 new cases of asthma (-3.0%) among 9.4 million residents. Residents outside the LEZ would also benefit from this scenario. Results indicated that the intervention could contribute to increasing inequalities. The comparison of scenarios underlined the value of extending the LEZ to include a wider zone (including 80 more municipalities surrounding Paris). This would lead to a more equitable spread of the benefits over the population.

CONCLUSION: Traffic control policies such as LEZ are difficult to accept for some categories of commuters and economic stakeholders. As of June 2019, the concertation process for the proposed Paris LEZ is still ongoing. This work provides authorities with detailed analyses of the options for this measure as well as information on related implications. It will help decision makers prioritize which preventive measures to introduce.