Université de Montréal, Canada.
Analyst. 2017 Feb 27;142(5):687-690. doi: 10.1039/c6an02378a.
Airborne particulate matter less than 2.5 μm in diameter (PM) negatively impacts air quality in cities throughout the world where it has been linked to increased cardiac and respiratory morbidity and mortality. For this reason PM standards have been established by many countries and the World Health Organization. However, these guidelines are regularly exceeded in North America, Europe and East Asia. While PM is often reported as a single atmospheric species, it is actually a mixture of organic and inorganic compounds. The organic fraction, termed organic aerosol (OA), contributes approximately 20-70% of the PM mass globally, and OA itself is a complex mixture of thousands of compounds. Characterizing the chemical properties of OA represents a major analytical challenge that has motivated the development of a range of new instruments. The focus of this perspective is the use of field-deployable mass spectrometers and in particular the Aerodyne Aerosol Mass Spectrometer (AMS) for chemically characterizing submicron particles. Field measurements of the composition of PM are directly relevant to evaluating its health impact because reductions in life expectancy due to PM vary according to composition. In addition, AMS measurements are especially useful for characterizing OA. The sources of OA are not well understood as evidenced by the performance of many air quality models, including those run by government agencies, which lack accurate and well constrained parameterizations for simulating secondary OA concentrations in urban regions. Given that OA is an important component of the total PM mass, this uncertainty makes accurate evaluation of the impact of PM on public health difficult, especially when evaluating future mitigation strategies. The development of the AMS has been a critical step towards addressing this public health challenge in that it provides quantitative data regarding particulate matter and OA concentration and composition that can be used to constrain uncertainties in air quality models.
空气中直径小于 2.5μm 的颗粒物（PM）会降低全球城市的空气质量，而这些颗粒物与心脏病和呼吸道疾病发病率和死亡率的上升有关。出于这个原因，许多国家和世界卫生组织都制定了 PM 标准。然而，在北美、欧洲和东亚，这些标准经常被超过。虽然 PM 通常被报道为一种单一的大气物质，但实际上它是有机和无机化合物的混合物。有机部分，称为有机气溶胶（OA），约占全球 PM 质量的 20-70%，而 OA 本身就是数千种化合物的复杂混合物。OA 的化学性质的表征代表了一个主要的分析挑战，这促使了一系列新仪器的发展。本观点的重点是使用现场可部署的质谱仪，特别是 Aerodyne 气溶胶质谱仪（AMS），用于对亚微米颗粒进行化学特性分析。PM 组成的现场测量与评估其健康影响直接相关，因为 PM 导致的预期寿命缩短因组成而异。此外，AMS 测量对于 OA 的特性分析特别有用。OA 的来源尚不清楚，这可以从许多空气质量模型的性能中得到证明，包括政府机构运行的模型，这些模型在模拟城市地区二次 OA 浓度方面缺乏准确和良好约束的参数化。鉴于 OA 是总 PM 质量的重要组成部分，这种不确定性使得准确评估 PM 对公众健康的影响变得困难，尤其是在评估未来的缓解策略时。AMS 的发展是应对这一公共卫生挑战的关键步骤，因为它提供了有关颗粒物和 OA 浓度和组成的定量数据，可用于约束空气质量模型中的不确定性。
