Real-world observations of reduced nitrogen and ultrafine particles in commercial cooking organic aerosol emissions
oleh: S. Kim, J. Machesky, D. R. Gentner, A. A. Presto
| Format: | Article |
|---|---|
| Diterbitkan: | Copernicus Publications 2024-01-01 |
Deskripsi
<p>Cooking is an important but understudied source of urban anthropogenic fine particulate matter (PM<span class="inline-formula"><sub>2.5</sub></span>). 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 <span class="inline-formula"><100</span> nm mobility diameter), with a mode diameter <span class="inline-formula"><50</span> 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 <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M4" display="inline" overflow="scroll" dspmath="mathml"><mrow><mi>m</mi><mo>/</mo><mi>z</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="23pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="55e7511b997f0b1e1b80fcef0834494e"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-24-1281-2024-ie00001.svg" width="23pt" height="14pt" src="acp-24-1281-2024-ie00001.png"/></svg:svg></span></span> 41, 43, and 55, though the composition (e.g., the ratio of oxygenated to reduced ions at specific <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M5" display="inline" overflow="scroll" dspmath="mathml"><mrow><mi>m</mi><mo>/</mo><mi>z</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="23pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="46f32566b65c77f385ccc58250dc589d"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-24-1281-2024-ie00002.svg" width="23pt" height="14pt" src="acp-24-1281-2024-ie00002.png"/></svg:svg></span></span>) varied across locations. All restaurant emissions included reduced-nitrogen species detected as <span class="inline-formula">C<sub><i>x</i></sub>H<sub><i>y</i></sub>N<sup>+</sup></span> fragments, making up <span class="inline-formula">∼15</span> % 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.</p>