Did policies to abate atmospheric emissions from traffic have a positive effect in London?

Abstract

A large number of policy initiatives are being taken at the European level, across the United Kingdom and in London to improve air quality and reduce population exposure to harmful pollutants from traffic emissions. Trends in roadside increments of nitrogen oxides (NO), nitrogen dioxide (NO), particulate matter (PM), black carbon (CBLK) and carbon dioxide (CO) were examined at 65 London monitoring sites for two periods of time: 2005-2009 and 2010-2014. Between 2005 and 2009 there was an overall increase in NO reflecting the growing evidence of real world emissions from diesel vehicles. Conversely, NO decreased by 10%·year from 2010 onwards along with PM (-28%·year) and black carbon (-11%·year). Downwards trends in air pollutants were not fully explained by changes in traffic counts therefore traffic exhaust emission abatement policies were proved to be successful in some locations. PM concentrations showed no significant overall change suggesting an increase in coarse particles which offset the decrease in tailpipe emissions; this was especially the case on roads in outer London where an increase in the number of Heavy Good Vehicles (HGVs) was seen. The majority of roads with increasing NO experienced an increase in buses and coaches. Changes in CO from 2010 onwards did not match the downward predictions from reduced traffic flows and improved fleet efficiency. CO increased along with increasing HGVs and buses. Polices to manage air pollution provided differential benefits across London's road network. To investigate this, k-means clustering technique was applied to group roads which behaved similarly in terms of trends to evaluate the effectiveness of policies to mitigate traffic emissions. This is the first time that London's roadside monitoring sites have been considered as a population rather than summarized as a mean behaviour only, allowing greater insight into the differential changes in air pollution abatement policies.

Designing vegetation barriers for urban air pollution abatement: a practical review for appropriate plant species selection

“…brake wear) are considered to be significant sources of PM, which is then re-suspended by trafficrelated turbulence 25,26 . In an examination of air pollutant trends in London between 2005-2009 and 2010-2014, Font and Fuller 27 found that abatement measures in some locations were offset by changes in traffic flow; that is, that increased non-exhaust sources of coarse PM, including road wear by heavier vehicles, offset reductions in exhaust emissions. This has implications for the assumed benefit of a move towards the use of electric vehicles for ambient air quality 28 .…”

Association between exposure to traffic-related air pollution and pediatric allergic diseases based on modeled air pollution concentrations and traffic measures in Seoul, Korea: a comparative analysis

“…In particular, understanding the association of allergic diseases with a specific source of air pollution is important because this enables the relevant authorities to establish a clear target of intervention for reducing air pollution and preventing subsequent adverse health effects. Specifically, exposure to traffic-related air pollution (TRAP) has become of particular interest because traffic-related interventions, such as implementation of diesel retrofit programs, restriction of high emission vehicles, and accommodation of energy-efficient vehicles, are highly practical options for reducing air pollution in many countries [18,19].…”

Characterization of Road Dust Emissions in Milan: Impact of Vehicle Fleet Speed

“…In spite of the large achievements in tail-pipe emission reductions due to the EUROx directives (AIRUSE, 2016), an important fraction of traffic emissions remain uncontrolled, namely non-exhaust emissions. Indeed, studies have demonstrated that the relative importance of non-exhaust emission is increasing, and is already becoming the dominant local source in cities Font and Fuller, 2016). Political and technological actions are therefore urgently needed, in order to regulate and minimize emissions from brakes, tires and road wear as well as from road dust resuspension.…”