AIR QUALITY MONITORING ON THE LONDON UNDERGROUND: DEVELOPING NEW UNDERSTANDING OF PARTICULATE MATTER VARIABILITY AND SUPPORTING MITIGATION STRATEGIES

空气污染是21世纪世纪最大的环境健康风险，因为它对健康产生有害影响，而且由于人类活动的加剧，对城市地区的居民产生了不成比例的影响。颗粒物（PM）通常被认为是最危险的污染物，因为它是由微观颗粒的异质混合物组成的（直径<10微米），可吸入，并可通过肺部进入血液。在伦敦，估计每年有4，000 - 9，000名伦敦人因暴露于空气污染而过早死亡，最近的发展已经看到传统的空气质量测量网络（例如LAQN）被较低成本的传感器（例如Breathe伦敦）成功地扩展，然而，伦敦内的许多监测不足的微环境仍然存在。伦敦地铁（LU）就是这样一个环境，每月有8800万人次。在LU上，颗粒物（PM1.0，PM2.5，PM10）是最普遍的污染物，其浓度通常比年平均浓度指南高出100倍。尽管如此，该系统仍在很大程度上未得到充分研究。目前，很少有人知道的PM在系统中的季节性或长期变化，不同来源的整体PM浓度的贡献，环境气象和季节性周期的作用，或清洁制度的有效性进行运输伦敦。这些不确定性每天都在影响着伦敦人，为了建设一个更健康的城市，这些不确定性是至关重要的。这个博士项目将通过开发一系列低成本的空气质量传感器来解决这些不确定性，这些传感器将同时部署在系统中的多个车站，无论是在确定的站台还是车站入口。这将允许对PM浓度进行长期（> 1年）监测，使用PM尺寸箱数浓度进行来源区分，对系统内的分散进行建模，并评估TfL将安装的持续清洁制度和过滤装置，作为LU内PM的管理选项。源分化将通过收集LU内的灰尘样本，将在QMUL实验室通过ICP-MS进行分析。这些方法将导致对LU污染的季节性周期的新见解，地面气象对污染物浓度的影响，允许提出缓解措施，并告知政策制定者围绕引入室内空气质量指南展开讨论。

Air pollution is the largest environmental health risk of the 21st century due to its detrimental health impacts, and disproportionate impacts on people living in urban areas as a result of heightened anthropogenic activities. Particulate matter (PM) is often viewed as the most dangerous pollutant, as it is made up of a heterogenic mixture of microscopic particles (<10 micrometres in diameter), is inhalable, and can pass through the lungs into the bloodstream.In London, an estimated 4,000-9,000 Londoners die prematurely due to air pollution exposure annually, with associated economic costs of around £1.4 to £3.8 billion yearly Recent developments have seen the traditional air quality measurement networks (e.g. LAQN) being successfully extended by lower-cost sensors (e.g. Breathe London), however, many under-monitored microenvironments within London remain. One such environment is the London Underground (LU), with 88 million journeys a month. On the LU, particulate matter (PM1.0, PM2.5, PM10) is the most prevalent pollutant, often reaching concentrations 100 times higher than annual mean concentration guidelines.Despite this, the system remains largely understudied. Currently, very little is known about the seasonal or long-term variability of PM in the system, the contribution of different sources to overall PM concentrations, the role of ambient meteorology and seasonal cycles, or the effectiveness of cleaning regimes conducted by Transport for London. These uncertainties continue to impact Londoners daily, and are vital to examine in order to build a healthier city.This PhD project will address these uncertainties by developing a range of low-cost air quality sensors to be deployed simultaneously across multiple stations in the system, both on identified platforms and station entrances. This will allow for long-term (> 1 year) monitoring of PM concentrations, source-differentiation using PM size bin number concentrations, modelling of dispersion within the system, and evaluation of ongoing cleaning regimes and filtration units to be installed by TfL as a management option for PM within the LU. Source differentiation will be supported by collecting dust samples within the LU that will be analysed in the QMUL labs by ICP-MS.These approaches will lead to new insights on the seasonal cycle of pollution on the LU, the impact of above ground meteorology on pollutant concentrations, allow for mitigation measures to be proposed, and inform policy makers to initiate discussions around the introduction of indoor air quality guidelines.