Public Health Impacts of UK's Clean Air Zones.

空气污染是英国最大的环境健康威胁。它每年导致30，000名75岁以下的人死亡，并使我们的经济损失200亿英镑。英国政府已承诺减少我们呼吸的空气中的颗粒物（PM），这是空气污染的有害成分，以满足世界卫生组织的指导。清洁空气区（CAZ）是采取有针对性的行动来改善空气质量的地区，在世界各地越来越多地计划。然而，我们不知道这些CAZ对空气污染水平或健康有什么影响。2019年4月，伦敦成为英国第一个实施大规模CAZ的城市，即超低排放区（ULEZ），覆盖伦敦中心地区，拥有20万居民。从2021年起，它将覆盖南北环形公路内的更大区域，那里有380万人。这项研究计划将查明ULEZ是否会改变空气质量，以及它对伦敦居民的健康有什么影响。然后，我们将重复研究，看看计划在伯明翰CAZ，以了解更多关于如何CAZ在不同的设置工作。决策者和公共卫生从业人员需要这些信息，以设计有效的干预措施，改善空气质量和人口健康。我们将对ULEZ进行自然实验研究，以确定其对空气质量，污染物成分，非传染性疾病和终身健康不平等的影响。为此，我们将完成四项补充研究。第一项研究将描述随着ULEZ的引入（2016-2024），空气中污染物数量的变化。我们将使用伦敦空气质量网络监测点的测量结果，使用我们开发的CMAQ城市模型来估计整个伦敦的空气质量。我们还将使用创新方法，将与交通有关的金属和多环芳烃纳入通常考虑的污染物范围。第二项研究将探讨随着ULEZ的引入，伦敦居民的健康是否有任何变化。我们将使用中断的时间序列方法来比较ULEZ实施之前（2016-2019）与之后（2019-2022）的健康结果。具体而言，观察呼吸道和心血管疾病的住院和初级保健咨询数量、婴儿出生体重和是否早产以及死亡人数。我们还将探讨ULEZ是否会根据人们的年龄、性别、种族、社会经济地位或先前存在的慢性疾病（多种发病率）对人们的健康产生不良影响。然后，我们会使用点过程回归模型，将健康数据与我们的空气质量模型联系起来，以描述污染物浓度与健康的关系。第三项研究将利用伦敦研究的结果预测计划中的伯明翰CAZ对空气质量和健康的影响。然后，我们将研究伯明翰的CAZ使用相同的方法应用于ULEZ的现实世界的影响，并将这些结果与我们预测的结果进行比较。最后，我们将把我们在伦敦和伯明翰的研究结果与一项关于空气污染如何影响儿童呼吸系统健康、身体活动和肥胖的研究（CHILL研究）结合起来，以更深入地了解CAZ如何对健康产生影响。具体来说，我们将完善一个逻辑模型来描述从CAZ到健康的途径，我们将应用健康影响研究所的成果评估周期框架来综合英国，欧洲和全球城市的政策影响，重点是健康不平等和多重发病率。该研究计划将提供设计有效的公共卫生干预措施所需的证据，以改善空气质量和城市居民的健康和福祉。

Air pollution is the greatest environmental threat to health in the UK. Each year it contributes to 30,000 deaths in people under the age of 75 and costs our economy £20 billion. The UK government has committed to reduce the amount of particulate matter (PM), a harmful component of air pollution, in the air we breathe to meet the World Health Organisation's guidance. Clean Air Zones (CAZ), areas where targeted action is taken to improve air quality, are increasingly planned across the world. However, we do not know what effect these CAZs have on air pollution levels or health. In April 2019 London was the first UK city to implement a large-scale CAZ, the Ultra Low Emission Zone (ULEZ) which covers an area of central London with 200,000 residents. From 2021 it will cover a larger area inside the North and South circular roads that is home to 3.8 million people. This programme of research will find out if the ULEZ changes air quality and what impact it has on the health of London's residents. We will then repeat the study looking at the planned CAZ in Birmingham to learn more about how CAZs work in different settings. This information is needed by policy makers and public health practitioners to design effective interventions that improve both air quality and population health. We will undertake a natural-experiment study of the ULEZ to determine its impact on air quality, pollutant composition, non-communicable disease and health inequalities throughout life.To do this we will complete four complementary research studies. The first study will describe the change to the amount of pollutants in the air as the ULEZ is introduced (2016-2024). We will use measurements from London's Air Quality Network of monitoring sites to estimate air quality across the whole of London using a model we have developed called the CMAQ-urban model. We will also use innovative methods to look beyond the commonly considered pollutants to include traffic related metals and polycyclic aromatic hydrocarbons. The second study will explore whether there is any change in the health of London residents as the ULEZ is introduced. We will use an interrupted time series approach to compare the occurrence of health outcomes before (2016-2019) the implementation of the ULEZ to after (2019-2022). Specifically, looking at the number of hospital admissions and primary care consultations for respiratory and cardiovascular diseases, babies' birth weights and whether they were born early, and the number of people who die. We will also explore whether the ULEZ disproportionally affects people's health based on their age, sex, ethnicity, socio-economic status or pre-existing chronic diseases (multi-morbidity). We will then use a point process regression model to link the health information to our air quality models to describe how the concentration of pollutants is related to health. The third study will predict the impact of the planned CAZ in Birmingham on air quality and health using the findings from the study in London. We will then study the real-world impact of Birmingham's CAZ using the same methods applied to the ULEZ and compare these results with those we predicted. Finally, we will bring together our findings from London and Birmingham with those from a study of how air pollution affects children's respiratory health, physical activity and obesity (CHILL study) to develop a deeper understanding of how CAZs have an impact on health. Specifically, we will refine a logic model to describe the pathways from CAZs to health and we will apply the Health Effects Institute's Outcomes Evaluation Cycle framework to synthesise policy implications for the UK, Europe and global cities, focused on health inequalities and multi-morbidity. This programme of research will provide the evidence that is needed to design effective public health interventions that improve air quality and the health and wellbeing of urban residents.