Five years of London's low emission zone: Effects on vehicle fleet composition and air quality

摘要

This paper uses registration and enforcement information to assess the impact of London's low emission zone on vehicle registrations, usage and air pollution. The zone was implemented in a staged process in 2008 to reduce the emissions of air pollutants of direct harm to human health. The zone targeted the worst polluters, specifically heavy diesel vehicles, buses and coaches by imposing minimum emissions standards on vehicles operating in an area covering most of Greater London. Several years on it remains unclear how successful the zone has been in meeting its stated objectives and what improvements in pollution levels can be attributed to the low emission zone. Results presented in this paper suggest the rate of fleet turnover for affected vehicle classes in London increased substantially when the zone was first introduced before returning to the national average in subsequent years. Early evidence for light commercial vehicles, which became subject to the scheme in early 2012, shows a similar effect is likely. Despite an overall growth in freight vehicles operating in London, the number of pre-Euro Ⅲ vehicles has dropped and this has been coupled with a switch from rigid vehicles to light commercial vehicles and articulated vehicles. Ambient air quality measurements show concentrations of particulate matter within the low emission zone have dropped by 2.46-3.07% compared to just over 1% for areas just outside the zone. However, no discernible differences are found for NO_x concentrations.