Ultrafine and Submicron Particles in the Urban Environment in Thailand - Size, Concentration, Composition and Health Impacts

众所周知，颗粒物对健康构成重大威胁，尤其是对城市居民，受影响最大的往往是社会上最贫穷的人。超细颗粒（尺寸小于100纳米）作为PM的一个组成部分，越来越多地与疾病和死亡有关。然而，文献中现有的许多研究都是基于来自发达国家的数据，特别是关于超细颗粒的数据，如果没有可靠的数据，就不可能确定泰国和曼谷这一重要污染物的趋势，因此，健康保护战略缺乏这一重要信息。此外，在大多数全球气候模式中，气溶胶颗粒是不确定性的最大单一来源，运输和工业部门产生的初级颗粒和气体前体，例如挥发性有机化合物（VOCs），对这一点贡献很大。因此，为了评估和减少这些活动对气候的影响，必须确定气体和粒子的排放源和水平。据我们所知，这项研究将首次报道泰国曼谷城市亚微米（小于1微米）尺寸范围内的超细颗粒（UFP）数量浓度和尺寸分布。随着泰国城市化进程的继续，这个特大城市的人口预计将会增加，更多的人将暴露在更高水平的气体和颗粒污染物中。我们将进行一项广泛的实验活动，结合颗粒浓度、大小分布测量和抽样，以及对颗粒成分的精确实验室分析、最先进的大气示踪剂分散实验、建模和来源分配技术，以确定这一重要健康风险的来源、排放因素、人类接触和吸入剂量。我们将在泰国的三个主要季节（干冷、干热和雨季）开展工作，以确定气候如何影响粒径分布和性质。我们还将研究其他区域颗粒源事件，如农业火灾，在这些事件发生的季节和非季节访问农村地区，以确定它们对颗粒浓度的影响。我们的目标是在使用非标准仪器进行尺寸分离的空气颗粒采样和使用比目前可用的更便宜的设备估计亚微米颗粒尺寸分布方面提供方法上的进步。通过获得这些关于不同区域各种微环境中典型水平的新信息，并通过确定来源和排放因素，就可以实现通过干预措施减少接触的直接公共卫生咨询，并采取初步步骤，让监管机构和政府机构参与进来，帮助实现减少微粒污染的目标，从而改善泰国和曼谷居民的健康和生活质量。从而减轻泰国政府目前因颗粒物对健康的不利影响而承担的重大经济成本负担。

It is well known that particulate matter (PM) poses a significant health risk, especially to urban dwellers, with often the poorest in society most affected. Ultrafine particles (size smaller than 100 nanometres), as a component of PM, are increasingly implicated in disease and mortality. However, much of the research available in the literature is based on data from the developed world, especially for ultrafine particles, and without robust data it is not possible to determine trends in this important pollutant for Thailand and Bangkok in particular, and strategies for health protection therefore lack this vital information. In addition, aerosol particles provide the single largest source of uncertainty in most global climate models, and production of primary particles and gas precursors e.g. Volatile Organic Compounds (VOCs) from the transport and industrial sectors contribute significantly to this. Therefore, in order for the impact of these activities on climate to be assessed and reduced, determination of sources and levels of emission of both gases and particles much be undertaken. This study will to our knowledge be the first to report ultrafine particle (UFP) number concentration and size distributions in the submicron (smaller than 1 micrometre) size range in urban Bangkok, Thailand. Population in this megacity is expected to rise as urbanisation continues in Thailand, with more people exposed to higher levels of gas and particle pollutants. We will carry out an extensive experimental campaign combining particle concentration, size distribution measurement and sampling with precise laboratory analysis for the particle composition, state-of-the-art atmospheric tracer dispersion experiments and modelling and source apportionment techniques to establish the sources, emission factors, human exposures and inhalation doses for this important health risk. We will undertake work in the three main seasons in Thailand (cool dry, hot dry and rainy) to determine how the climate influences particle size distribution and properties. We will also examine other regional particle source events, such as agricultural fires, visiting rural areas in and out of season for these events to determine their impact on particle concentrations. We aim to provide methodological advances in using non-standard instrumentation for size-segregated airborne particle sampling and for estimation of submicron particle size distributions using cheaper devices than are presently available. By obtaining this new information on typical levels in a variety of microenvironments, in different regions and by identifying sources and emissions factors, direct public health advice on exposure reduction through interventions could be achieved, and first steps taken to engage regulatory bodies and government agencies to aid in their target of reducing particulate pollution to improve the health and quality of life of Thailand and Bangkok residents, and hence reducing the significant current economic cost burden to the Thailand government associated with adverse health impact of particulates.