Background

Transport-related air and noise pollution, exposures linked to adverse health outcomes, varies within cities potentially resulting in exposure inequalities. Relatively little is known regarding inequalities in personal exposure to air pollution or transport-related noise.

Objectives

Our objectives were to quantify socioeconomic and ethnic inequalities in London in 1) air pollution exposure at residence compared to personal exposure; and 2) transport-related noise at residence from different sources.

Methods

We used individual-level data from the London Travel Demand Survey (n = 45,079) between 2006 and 2010. We modeled residential (CMAQ-urban) and personal (London Hybrid Exposure Model) particulate matter <2.5 μm and nitrogen dioxide (NO₂), road-traffic noise at residence (TRANEX) and identified those within 50 dB noise contours of railways and Heathrow airport. We analyzed relationships between household income, area-level income deprivation and ethnicity with air and noise pollution using quantile and logistic regression.

Results

We observed inverse patterns in inequalities in air pollution when estimated at residence versus personal exposure with respect to household income (categorical, 8 groups). Compared to the lowest income group (<£10,000), the highest group (>£75,000) had lower residential NO₂ (−1.3 (95% CI −2.1, −0.6) μg/m³ in the 95th exposure quantile) but higher personal NO₂ exposure (1.9 (95% CI 1.6, 2.3) μg/m³ in the 95th quantile), which was driven largely by transport mode and duration. Inequalities in residential exposure to NO₂ with respect to area-level deprivation were larger at lower exposure quantiles (e.g. estimate for NO₂ 5.1 (95% CI 4.6, 5.5) at quantile 0.15 versus 1.9 (95% CI 1.1, 2.6) at quantile 0.95), reflecting low-deprivation, high residential NO₂ areas in the city centre. Air pollution exposure at residence consistently overestimated personal exposure; this overestimation varied with age, household income, and area-level income deprivation. Inequalities in road traffic noise were generally small. In logistic regression models, the odds of living within a 50 dB contour of aircraft noise were highest in individuals with the highest household income, white ethnicity, and with the lowest area-level income deprivation. Odds of living within a 50 dB contour of rail noise were 19% (95% CI 3, 37) higher for black compared to white individuals.

Conclusions

Socioeconomic inequalities in air pollution exposure were different for modeled residential versus personal exposure, which has important implications for environmental justice and confounding in epidemiology studies. Exposure misclassification was dependent on several factors related to health, a potential source of bias in epidemiological studies. Quantile regression revealed that socioeconomic and ethnic inequalities in air pollution are often not uniform across the exposure distribution.

中文翻译：

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伦敦空气和噪音污染中的社会经济和种族不平等

背景

与交通相关的空气和噪音污染，即与不良健康结果相关的暴露，在城市内各不相同，可能导致暴露不平等。关于个人暴露于空气污染或与交通相关的噪音中的不平等，人们知之甚少。

目标

我们的目标是量化伦敦的社会经济和种族不平等： 1）住宅空气污染暴露与个人暴露相比；2) 来自不同来源的住宅与交通相关的噪音。

方法

我们使用了 2006 年至 2010 年间伦敦旅行需求调查 (n = 45,079) 的个人数据。我们模拟了住宅（CMAQ-城市）和个人（伦敦混合暴露模型）颗粒物 <2.5 μm 和二氧化氮（NO ₂） ，住宅道路交通噪声 (TRANEX)，并确定了铁路和希思罗机场 50 dB 噪声等值线内的噪声。我们使用分位数和逻辑回归分析了家庭收入、地区收入剥夺和种族与空气和噪音污染之间的关系。

结果

我们观察到在居住地与个人暴露在家庭收入（分类，8组）方面的空气污染不平等的相反模式。与最低收入组（<10,000 英镑）相比，最高收入组（>75,000 英镑）的住宅 NO ₂较低（-1.3 (95% CI -2.1, -0.6) μg/m ³在第 95 个暴露分位数）但较高个人二氧化氮暴露（在第 95_个分位数为1.9 (95% CI 1.6, 2.3) μg/m ³），这主要受运输方式和持续时间的影响。在较低的暴露分位数（例如，对 NO _2的估计5.1 (95% CI 4.6, 5.5) 在分位数 0.15 与 1.9 (95% CI 1.1, 2.6) 在分位数 0.95)，反映了市中心的低贫困、高住宅 NO _2区域。住宅的空气污染暴露始终高估个人暴露；这种高估因年龄、家庭收入和地区收入剥夺而异。道路交通噪音的不平等普遍较小。在逻辑回归模型中，家庭收入最高、白人种族和地区收入剥夺最低的个人生活在 50 dB 飞机噪音等值线内的几率最高。与白人相比，黑人生活在 50 dB 铁路噪声等值线内的几率高 19% (95% CI 3, 37)。

结论

模拟住宅与个人暴露在空气污染暴露方面的社会经济不平等是不同的，这对环境正义和流行病学研究的混淆具有重要意义。暴露错误分类取决于与健康相关的几个因素，这是流行病学研究中潜在的偏见来源。分位数回归显示，空气污染中的社会经济和种族不平等在暴露分布中通常并不均匀。