Molecular Level Understanding of New Particle Formation in the Urban Atmosphere: Contribution of Local Pollutants

城市大气中新颗粒形成的分子水平理解：当地污染物的贡献

• 批准号: NE/V001523/1
• 负责人: Roy Harrison
• 金额: $ 81.52万
• 依托单位: University of Birmingham
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FV001523%2F1
• 关键词: Molecular; Level; Understanding; New; Particle

Airborne particles are made up of tiny specks of solid matter or liquid droplets floating in the air, too small to be seen individually by the naked eye. Gaining a good understanding of these particles is important for a number of reasons including the following:- breathing high concentrations is bad for human health, having been associated with increased hospital admissions and reduced life expectancy. More deaths occur globally due to airborne particle exposure than from malaria and AIDS combined; - small particles influence the formation of clouds, and their concentration in the atmosphere has a direct and indirect influence on climate by affecting the amount of sunshine reflected back to space; - high concentrations of particles in the air cause a loss of visibility and the hazes that can be seen on polluted days.One of the most pressing current scientific questions in atmospheric science is the formation of new particles in the atmosphere from gases by processes known as nucleation. Recent advances in instrumentation have allowed direct observation of nucleation processes as gas molecules join together to form new particles. Up until now these processes have been studied mostly under very controlled conditions in reaction chambers and in clean mountain-top air. The processes occurring in heavily polluted air are different from these and our proposal is to make measurements of particle nucleation processes in polluted atmospheres in cities where the composition is very well characterised. This will allow us to evaluate the contribution of pollutant emissions to particle formation processes and their contribution to new particle production in the urban atmosphere, as well as processes unconnected with road traffic emissions. Field measurements will be made in Beijing and Barcelona, cities where new particle formation occurs frequently, and where two sampling sites will be established, one at the kerbside of a major highway and the other at a background location. These will be equipped with highly sophisticated state-of-the-art instruments which will identify the times when new particles are forming in the atmosphere and will determine the chemical characteristics of the molecules which are condensing into clusters to form the new particles. Both cities have high sunshine intensity (needed for frequent new particle formation), but widely differing pollution climates. The outcome of the work will be a much better understanding of the processes responsible for new particle formation through nucleation in polluted air. Such knowledge will allow better design of mitigation strategies for reduction of ultrafine particle concentrations as well as providing the necessary knowledge to improve climate prediction models where currently one of the largest uncertainty relates to the role of airborne particles in affecting climate. In the future, it is expected that reductions in pollutant emissions and improved air quality may affect new particle formation. Lower concentrations of emitted particles will favour increased new particle formation, while reductions in sulphur dioxide and organic compounds are expected to be unfavourable. Well-designed numerical models are needed to predict the net future impacts upon new particle formation, and hence both urban particle concentrations and cloud condensation nuclei in more remote locations.

空气中的颗粒由漂浮在空气中的微小固体物质或液滴组成，它们太小，肉眼无法单独看到。充分了解这些颗粒非常重要，原因有很多，包括： - 呼吸高浓度颗粒物对人类健康有害，与住院人数增加和预期寿命缩短有关。全球范围内因接触空气颗粒而死亡的人数比疟疾和艾滋病死亡人数的总和还要多； - 小颗粒影响云的形成，它们在大气中的浓度通过影响反射回太空的阳光量对气候产生直接和间接的影响； - 空气中高浓度的颗粒物会导致能见度下降，并且在污染的日子里会出现雾霾。当前大气科学中最紧迫的科学问题之一是通过称为“气体”的过程在大气中形成新的颗粒物。成核。仪器的最新进展允许直接观察气体分子结合在一起形成新粒子的成核过程。到目前为止，这些过程主要是在反应室和洁净的山顶空气中非常受控的条件下进行的。严重污染空气中发生的过程与这些不同，我们的建议是在成分非常明确的城市中测量污染大气中的颗粒成核过程。这将使我们能够评估污染物排放对颗粒形成过程的贡献及其对城市大气中新颗粒产生的贡献，以及与道路交通排放无关的过程。现场测量将在北京和巴塞罗那这两个新颗粒形成频繁的城市进行，并将建立两个采样点，一个位于主要高速公路的路边，另一个位于背景位置。这些设备将配备高度复杂的最先进仪器，这些仪器将识别大气中新颗粒形成的时间，并确定凝结成簇形成新颗粒的分子的化学特性。两个城市的日照强度都很高（频繁形成新颗粒所需），但污染气候却截然不同。这项工作的结果将是更好地理解污染空气中通过成核形成新颗粒的过程。这些知识将有助于更好地设计减少超细颗粒浓度的缓解策略，并提供必要的知识来改进气候预测模型，目前最大的不确定性之一与空气中颗粒在影响气候中的作用有关。未来，预计污染物排放的减少和空气质量的改善可能会影响新颗粒的形成。较低浓度的排放颗粒将有利于增加新颗粒的形成，而二氧化硫和有机化合物的减少预计是不利的。需要精心设计的数值模型来预测未来对新粒子形成的净影响，从而预测城市粒子浓度和更偏远地区的云凝结核。

项目成果

The Effect of Meteorological Conditions and Atmospheric Composition in the Occurrence and Development of New Particle Formation (NPF) Events in Europe

气象条件和大气成分对欧洲新粒子形成（NPF）事件发生和发展的影响

• 发表时间: 2023
• 期刊: Atmos. Chem. Phys.
• 作者: Bousiotis; D.
• 通讯作者: D.

Measurement Report: Interpretation of Wide-Range Particulate Matter Size Distributions in Delhi

测量报告：德里大范围颗粒物尺寸分布的解释

• 发表时间: 2023
• 期刊: Atmos. Chem. Phys.
• 作者: Alver Sahin Ü.