Medical Research Council (MRC)-Public Health England Centre for Environmental Health, National Institute for Health Research Biomedical Research Centre at Guy's and St Thomas' National Health Service Foundation Trust and King's College London, London, UK.
Asthma UK Centre for Applied Research, Barts Institute of Population Health Sciences, Queen Mary University of London, London, UK.
Lancet Public Health. 2019 Jan;4(1):e28-e40. doi: 10.1016/S2468-2667(18)30202-0. Epub 2018 Nov 15.
Low 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.
We 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 [NO]) and particulate matter with a diameter of less than 2·5 μm (PM) and less than 10 μm (PM) and lung function: postbronchodilator forced expiratory volume in 1 s (FEV, 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.
The percentage of children living at addresses exceeding the EU limit value for annual NO (40 μg/m) fell from 99% (444/450) in 2009 to 34% (150/441) in 2013. Over this period, we identified a reduction in NO at both roadside (median -1·35 μg/m 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 PM. The effect on PM was equivocal. We found no association between postbronchodilator FEV and annual residential pollutant attributions. By contrast, FVC was inversely correlated with annual NO (-0·0023 L/μg per m; -0·0044 to -0·0002; p=0·033) and PM (-0·0090 L/μg per m; -0·0175 to -0·0005; p=0·038).
Within 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.
National 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.
低排放区（LEZ）是一种越来越常见但尚未评估的干预措施，旨在改善城市空气质量和公共健康。我们研究了伦敦 LEZ 对空气质量和儿童呼吸健康的影响。
我们在英国伦敦市中心的 2164 名 8-9 岁的小学生中进行了一项连续的年度横断面研究，该研究于 2008 年 2 月伦敦 LEZ 引入后进行。我们研究了模型化的氮氧化物（包括二氧化氮[NO]）和小于 2.5μm（PM）和小于 10μm（PM）的颗粒物暴露与肺功能（支气管扩张后 1 秒用力呼气量[FEV]，主要结局）、用力肺活量（FVC）以及呼吸或过敏症状之间的关联。我们根据每个孩子的家庭和学校地址以及空间分辨率估计值，为每个孩子评估前 3 小时（0600-0900 小时）、24 小时和 7 天分配年度暴露值，以隔离长期和短期影响。
居住在年 NO 浓度超过欧盟限值（40μg/m）的家庭地址的儿童比例从 2009 年的 99%（444/450）下降到 2013 年的 34%（150/441）。在此期间，我们发现路边（中位数每年 -1.35μg/m；95%CI -2.09 至 -0.61；p=0.0004）和背景位置（-0.97；-1.56 至 -0.38；p=0.0013）的 NO 浓度均有所降低，但 PM 浓度没有降低。PM 的影响则不明确。我们发现支气管扩张后 FEV 与年度住宅污染物归属之间没有关联。相比之下，FVC 与年度 NO（-0.0023L/μg/m；-0.0044 至 -0.0002；p=0.033）和 PM（-0.0090L/μg/m；-0.0175 至 -0.0005；p=0.038）呈负相关。
在伦敦 LEZ 内，儿童的肺活量较小与较高的年度空气污染物暴露有关。尽管在伦敦 LEZ 实施期间，高度污染的城市地区空气质量有所改善，但在此期间，我们没有发现儿童肺部变小比例减少的证据。减少排放的干预措施可能会改善儿童的健康。
英国国民健康保险制度 Guys 和 St Thomas' 国民健康服务基金会信托基金和国王学院伦敦、NHS Hackney、Lee Him 捐赠以及 Felicity Wilde 慈善信托基金的国家卫生研究院生物医学研究中心资助。
