Lecture
This lecture discusses the effects of low nitrogen monoxide (NO) concentrations on secondary particle formation in the atmosphere. The instructor presents findings that highlight the nonlinear nature of atmospheric chemical processes, particularly how low NO levels influence the production of highly oxygenated organic molecules (HOM) and new particle formation. The lecture is divided into two main parts: first, it examines the pivotal role of NO in generating HOMs, which are crucial for new particle formation; second, it explores how low NO conditions can activate nocturnal nitrogen chemistry, leading to increased particulate nitrate concentrations in urban areas. The instructor emphasizes the importance of understanding these processes in the context of climate change and urban pollution, providing insights into the complex interactions between nitrogen compounds and atmospheric chemistry. The findings are relevant for policymakers and stakeholders aiming to mitigate air pollution and its health impacts, particularly in urban environments where NO emissions are being regulated.