Identification and Verification of Ultrafine Particle Affinity Zones in Urban Neighbourhoods / A Proof of Concept Proposal

最近的研究表明，在英国城市的大气中吸入污染微粒会导致或恶化一些呼吸和心血管疾病，甚至导致在污染特别严重的日子里，弱势群体的死亡人数增加。微粒污染是由存在于空气中的各种大小不同的悬浮粒子组成的。有证据表明，被称为超细颗粒（UFP）的最小颗粒毒性最大，可能与它们的化学成分无关。据信，道路车辆排放是UFP的主要来源（尽管这在英国尚未得到证实），尽管许多烹饪活动也会产生高浓度UFP。然而，并不是每个人都以同样的方式受到影响，这在一定程度上是由于空气中UFP的浓度在整个城市中不是均匀的，而是差异很大——不仅在地区之间，而且在当地社区之间，甚至从一条街到另一条街。因此，任何人的肺部受到的UFP剂量可能与其他人有很大不同，这不仅取决于他们住在哪里，还取决于他们在哪里工作或学习，以及他们的旅行方式。为了判断吸入超长纤维是否真的会对人们的健康造成不良影响，有必要找到一种方法来评估不同公民（特别是弱势群体）接触超长纤维的程度。在一个城市的每个家庭和工作场所放置UFP监视器是不现实的。另一方面，在一个城市的固定位置放置一个单一的监视器，以便它代表该城市中每个人的暴露情况（就像对一些气体污染物，如二氧化硫所做的那样），由于城市地区浓度的高度可变性，对于UFP是不合适的。目前，第三种方法/色散建模/不是UFP的可行选择，因为它需要我们尚未掌握的关于排放源的非常详细的信息。我们在知识方面的这些缺陷使我们无法正确量化UFP对公共卫生构成的威胁，也无法制定和评估任何减少这种威胁的战略。测量技术的最新发展为克服这一僵局提供了机会。该提案结合了曼彻斯特大学内三个团队的专业知识，将大气测量与地理信息科学（GISc）和环境健康研究人员联系起来。我们一起设计了一个研究项目，在这个项目中，我们开始研究曼彻斯特居民区小规模（相邻街道之间）室外浓度的空间变异性。经过测量，浓度的空间格局与来源的可变性（如交通密度）和描述该社区内受照射人口的格局（如白天人口密度）有关。从这一分析中，我们可以定义浓度变化不大的区域（在邻里尺度上）。项目的剩余部分集中在实验上比较这些区域之间的浓度，并逐渐建立一个关于UFP浓度如何以及最重要的是为什么在曼彻斯特市的大部分地区变化的图片。一旦完成，该项目将为后续研究提供基础，使研究人员能够比目前更有信心地量化城市居民的暴露情况，并在少数固定地点或单个地点安装更复杂的监测仪器，更清楚地了解一个地点的测量结果如何与整个城市地区的公民暴露情况有关。

Recent research has revealed that inhalation of particulate pollution in the atmosphere of British cities can cause or worsen a number of respiratory and cardiovascular conditions, even leading to an increase in the number of deaths amongst vulnerable persons on especially polluted days. Particulate pollution consists of a wide range of substances present in the air as suspended particles of a wide range of sizes. There is some evidence that the smallest particles, known as ultrafine particles (or UFP), are the most toxic, possibly irrespective of their chemical composition. It is believed that road vehicle emissions are the major source of UFP (although this is yet to be verified in the UK), although many cooking activities can also generate high concentrations. However, not everyone is affected in the same way and this will partly be due to the way that the concentration of UFP in the air is not uniform across a city, but varies enormously - not only between districts, but between local neighbourhoods and even from one street to another. Thus, the dose of UFP to the lungs of any one individual can be considerably different to any other individual depending upon not only exactly where they live, but also where they work or study and how they travel. In order to judge whether or not inhalation of UFP is genuinely causing ill health amongst the population it is necessary to find a way of assessing how much UFP different citizens (and especially vulnerable sub-groups) are exposed to. It is not practical to place UFP monitors in every home and workplace across a city. On the other hand, placing a single monitor in a fixed location within a conurbation so that it represents the exposure of everyone within that conurbation (as is done for some gaseous pollutants, such as sulphur dioxide) is not appropriate for UFP due to the high degree of variability in concentrations across an urban area. A third method / dispersion modelling / is not a viable option for UFP at present as it requires very detailed information on emission sources that we do not yet have. These shortcomings in our knowledge are preventing us from correctly quantifying the threat UFP poses public health and from developing and assessing any strategies to reduce this threat. Recent developments in measurement technology now present an opportunity to overcome this impasse. This proposal combines the expertise of three teams within the University of Manchester linking atmospheric measurements with Geographical Information Science (GISc) and environmental health researchers. Together, we have devised a programme of research in which we start to look at spatial variability in outdoor concentrations on a small scale (between adjacent streets) in residential neighbourhoods of Manchester. Measurements are made and spatial patterns in concentrations are related to variability in sources (such as traffic density) and to patterns describing the exposed population within that neighbourhood (such as the daytime population density). From this analysis we can define zones (at the neighbourhood scale) within which concentrations vary little. The remainder of the project is focussed upon experimentally comparing concentrations between these zones and gradually building up a picture of how and most importantly, why UFP concentrations vary across a large segment of the city of Manchester. Once complete, the project will have provided a foundation for subsequent research by allowing researchers to quantify the exposure of urban citizens with much more confidence than at present, and to site more sophisticated monitoring instrumentation at a small number of fixed locations, or a single one, with a much clearer understanding of how measurements at this one location can relate to exposure of citizens across a wide urban area.