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.

空气中的颗粒是由固体物质的微小斑点或漂浮在空气中的液滴组成的，肉眼太小，无法单独看到。出于多种原因包括以下原因，对这些粒子有良好的了解很重要： - 呼吸高浓度对人类健康不利，与医院的入院增加和预期寿命降低有关。由于空气传播的颗粒暴露，全球死亡人数多于疟疾，艾滋病总和。 - 小颗粒会影响云的形成，它们在大气中的浓度通过影响反射回空间的阳光的量对气候产生直接和间接的影响； - 空气中高浓度的颗粒会导致可见度丧失和在受污染的日子中看到的危险。大气科学中当前最紧迫的科学问题之一是通过称为成核的过程从气体中形成新颗粒。仪器的最新进展允许直接观察成核过程，因为气体分子结合在一起形成新颗粒。到目前为止，这些过程大多在反应室和干净的山顶空气中的非常受控的条件下进行了研究。在严重污染的空气中发生的过程与这些过程不同，我们的建议是对构成表征很好的城市中污染大气中的粒子成核过程进行测量。这将使我们能够评估污染物对颗粒形成过程的贡献及其对城市气氛中新颗粒产生的贡献，以及与道路交通排放无关的过程。将在北京和巴塞罗那，经常发生新粒子形成的城市中进行现场测量，并在其中建立两个采样位点，一个在主要高速公路的Kerbside，另一个位于背景位置。这些将配备高度复杂的最先进的仪器，这些仪器将确定新颗粒在大气中形成的时间，并确定分子的化学特性，这些分子的化学特性将凝结成簇以形成新颗粒。这两个城市都有高阳光强度（需要频繁形成新的颗粒），但污染气候却大不相同。这项工作的结果将更好地理解通过污染空气中的成核来导致新粒子形成的过程。这种知识将允许更好地设计缓解策略，以减少超细颗粒浓度，并提供必要的知识来改善气候预测模型，而气候预测模型当前最大的不确定性之一与空中粒子在影响气候中的作用有关。将来，预计污染物排放和改善空气质量的减少可能会影响新的颗粒形成。较低的发射颗粒将有利于增加的新颗粒形成，而二氧化硫的减少和有机化合物的减少预计将不利。需要精心设计的数值模型来预测对新颗粒形成的未来净影响，因此，在更偏远的位置中，城市粒子浓度和云凝结核都既有。

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

• DOI: 10.5194/acp-2020-555
• 发表时间: 2020-08
• 期刊: Atmospheric Chemistry and Physics
• 影响因子: 6.3
• 作者: Dimitrios Bousiotis;J. Brean;Francis D. Pope;M. Dall’Osto;X. Querol;A. Alastuey;Noemí Pérez;T. Petäjä;A. Massling;J. Nøjgaard;C. Nørdstrom;G. Kouvarakis;S. Vratolis;Konstantinos Eleftheriadis;J. Niemi;H. Portin;A. Wiedensohler;K. Weinhold;M. Merkel;T. Tuch;Roy M. Harrison

Measurement report: Interpretation of wide-range particulate matter size distributions in Delhi

• DOI: 10.5194/acp-22-5415-2022
• 发表时间: 2022-04-25
• 期刊: ATMOSPHERIC CHEMISTRY AND PHYSICS
• 影响因子: 6.3
• 作者: Sahin, Ulku Alver;Harrison, Roy M.;Verma, Rulan
• 通讯作者: Verma, Rulan