Climate, air quality and health impacts of transport policies in cities

Abstract

Environmental policies in cities have failed to effectively reduce air pollutants and greenhouse gas emissions to levels not detrimental to our environment and the health of the rapidly growing urban population. Most of the air pollutants originate from the same sources as greenhouse gases; the burning of fossil fuels and the urban transport sector are significant emitters of both. This dissertation examines the interactions between measures designed to tackle air pollution and reduce CO2 emissions in the transport sector in cities, with London and Mexico City as case study cities. Transport policies proposed for London by its authorities were reviewed, and from them, transport policy scenarios were developed and modelled. Technological and behavioural change transport policy scenarios were studied, including the implementation of low emission zones, vehicle electrification, reduction of car use through the promotion of active travel modes, and construction of cycle lanes. The BRUTAL sub-model of the UK Integrated Assessment Model was used to estimate CO2 emissions and air pollutants (NOX, NO2, PM10 and PM2.5) emissions and concentrations projected to 2030. Monetised benefits for the reduction in exposure to air pollution and the offset price for CO2 mitigation were calculated. For Mexico City, a more straightforward approach was used, assessing data from the emissions inventory to explore which strategies might be useful in reducing emissions from road transport. Health impact assessment approach was used to estimate the health impacts of air pollution exposure and physical activity in both cities. Technological strategies are effective at reducing NOX pollution and CO2 emission. Behavioural change strategies yield significant reductions in particulate matter pollution. Behavioural change scenarios also deliver the most significant health benefits through an increase in physical activity. For Mexico City, the renewal of the old vehicle fleet could bring significant air pollutant emissions reductions. Future work should assess the feasibility of the scenarios.