Impact of London's low emission zone on air quality and children's respiratory health: a sequential annual cross-sectional study

Abstract

SummaryBackgroundLow emission zones (LEZ) are an increasingly common, but unevaluated, intervention aimed at improving urban air quality and public health. We investigated the impact of London's LEZ on air quality and children's respiratory health.MethodsWe did a sequential annual cross-sectional study of 2164 children aged 8–9 years attending primary schools between 2009–10 and 2013–14 in central London, UK, following the introduction of London's LEZ in February, 2008. We examined the association between modelled pollutant exposures of nitrogen oxides (including nitrogen dioxide [NO2]) and particulate matter with a diameter of less than 2·5 μm (PM2·5) and less than 10 μm (PM10) and lung function: postbronchodilator forced expiratory volume in 1 s (FEV1, primary outcome), forced vital capacity (FVC), and respiratory or allergic symptoms. We assigned annual exposures by each child's home and school address, as well as spatially resolved estimates for the 3 h (0600–0900 h), 24 h, and 7 days before each child's assessment, to isolate long-term from short-term effects.FindingsThe percentage of children living at addresses exceeding the EU limit value for annual NO2 (40 μg/m3) fell from 99% (444/450) in 2009 to 34% (150/441) in 2013. Over this period, we identified a reduction in NO2 at both roadside (median −1·35 μg/m3 per year; 95% CI −2·09 to −0·61; p=0·0004) and background locations (−0·97; −1·56 to −0·38; p=0·0013), but not for PM10. The effect on PM2·5 was equivocal. We found no association between postbronchodilator FEV1 and annual residential pollutant attributions. By contrast, FVC was inversely correlated with annual NO2 (−0·0023 L/μg per m3; −0·0044 to −0·0002; p=0·033) and PM10 (−0·0090 L/μg per m3; −0·0175 to −0·0005; p=0·038).InterpretationWithin London's LEZ, a smaller lung volume in children was associated with higher annual air pollutant exposures. We found no evidence of a reduction in the proportion of children with small lungs over this period, despite small improvements in air quality in highly polluted urban areas during the implementation of London's LEZ. Interventions that deliver larger reductions in emissions might yield improvements in children's health.FundingNational Institute for Health Research Biomedical Research Centre at Guy's and St Thomas' National Health Service (NHS) Foundation Trust and King's College London, NHS Hackney, Lee Him donation, and Felicity Wilde Charitable Trust.

Associations between ambient air pollution and daily incidence of pediatric hand, foot and mouth disease in Ningbo, 2014–2016: a distributed lag nonlinear model

“…A study published in 2009 found no significant cross-sectional association between NO 2 concentrations and respiratory and allergic disorders in adults [39]. Lan et al investigated the effects of NO 2 on children's respiratory health and found that children's lung function indicators, such as forced vital capacity, were inversely correlated with annual NO 2 levels (−0.0023 l/μg per m 3 ; −0.0044 to −0.0002; P = 0.033) [40].…”

Inequalities in Exposure to Nitrogen Dioxide in Parks and Playgrounds in Greater London

“…Air pollution-related health effects in children include reduced respiratory function [2], asthma [3], obesity [4], and reduced cognition [5]. A study of school children in London found associations of NO 2 exposure with long-term reductions in lung capacity (forced vital capacity [FVC]) [6]. In Australia, decreased lung capacity was measured even in the presence of relatively low levels of ambient NO 2 [7] and, in Southern California, the magnitude of lung damage from NO 2 exposure was roughly equivalent to maternal smoking [8].…”

Air Pollution and Asthma: Critical Targets for Effective Action

“…those fuelled by diesel, include levies on fuel, surcharges for parking and the introduction of low-emission zones (LEZ). However, whilst large-scale LEZs can deliver improvements in urban air quality, data suggest that, at least in densely populated European cities, more ambitious schemes are required to meet legislative limits and deliver improvements to childhood respiratory health, including asthma symptoms [ 35 ]. The introduction and rigorous evaluation of zones with greater reductions in pollutant concentrations are clearly warranted and may benefit from adjuvant clean air zones that introduce no vehicle idling areas, minimise congestion and support active and low-emission travel through the integration of public transport networks, including park-and-ride schemes.…”