Real-world observations of reduced nitrogen and ultrafine particles in commercial cooking organic aerosol emissions
Real-world observations of reduced nitrogen and ultrafine particles in commercial cooking organic aerosol emissions
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DOI：
10.5194/acp-24-1281-2024
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发表时间：
2024-01
影响因子：
6.3
通讯作者：
Sunhye Kim;J. Machesky;D. Gentner;A. Presto
中科院分区：
文献类型：
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作者：
Sunhye Kim;J. Machesky;D. Gentner;A. Presto
摘要。烹饪是城市人为细颗粒物（PM2.5）的一个重要来源，但尚未得到充分研究。利用移动实验室，我们测量了城市餐馆烟雾中的PM大小和组成。尺寸分布测量表明，餐馆是城市超细颗粒（ufp，粒径<100 nm迁移直径的颗粒）的来源，样本餐馆的模态直径<50 nm，颗粒数浓度（pnc，粒径的代表）相对于城市背景显著升高。在我们的观察中，餐馆排放的PM质量几乎完全是有机气溶胶（OA）。气溶胶质谱显示，虽然大多数餐馆的排放是相似的，但存在关键的质谱差异。所有的餐馆都在m/z 41,43和55处排放OA，尽管其组成（例如，特定m/z下氧合离子与还原离子的比例）因地点而异。所有餐馆的排放物都含有以CxHyN+碎片形式检测到的还原氮，占羽流中测量的OA质量的约15%，具有降低的分子官能团（例如胺，亚胺），通常伴随着含氧官能团。减少的氮排放量最大的是一家商业面包面包店（即OA质量的30% - 50%），突出了餐馆之间的显著差异及其对城市ufp和减少的氮排放的重要性。
Abstract. Cooking is an important but understudied source of urban anthropogenic fine particulate matter (PM2.5). Using a mobile laboratory, we measured PM size and composition in urban restaurant plumes. Size distribution measurements indicate that restaurants are a source of urban ultrafine particles (UFPs, particles <100 nm mobility diameter), with a mode diameter <50 nm across sampled restaurants and particle number concentrations (PNCs, a proxy for UFPs) that were substantially elevated relative to the urban background. In our observations, PM mass emitted from restaurants was almost entirely organic aerosol (OA). Aerosol mass spectra show that while emissions from most restaurants were similar, there were key mass spectral differences. All restaurants emit OA at m/z 41, 43, and 55, though the composition (e.g., the ratio of oxygenated to reduced ions at specific m/z) varied across locations. All restaurant emissions included reduced-nitrogen species detected as CxHyN+ fragments, making up ∼15 % of OA mass measured in plumes, with reduced molecular functionalities (e.g., amines, imides) that were often accompanied by oxygen-containing functional groups. The largest reduced-nitrogen emissions were observed from a commercial bread bakery (i.e., 30 %–50 % of OA mass), highlighting the marked differences between restaurants and their importance for emissions of both urban UFPs and reduced nitrogen.