Real-world observations of ultrafine particles and reduced nitrogen in commercial cooking organic aerosol emissions

Abstract

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 diameter), with a mode diameter <50 nm across sampled restaurants and particle number concentrations (PNC, a proxy for UFPs) that were substantially elevated relative to the urban background. The majority of observed PM was organic aerosol (OA) by mass. 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.

Increasing Contributions of Temperature-Dependent Oxygenated Organic Aerosol to Summertime Particulate Matter in New York City

“…Overall, the contribution of these primary-like OA factors has decreased compared to prior measurements in Queens, with HOA and COA decreasing by 47% and 42% since 2009, respectively . While cooking-related emissions remain important for urban (and indoor) air quality given their mitigation challenges, the reduction in COA concentrations suggests some reductions in COA source contributions at the Queens site since 2009, though further studies are necessary to confirm this trend across larger spatial scales.…”