Articles | Volume 25, issue 21
https://doi.org/10.5194/acp-25-14825-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/acp-25-14825-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
14 Nov 2025
Research article |
| 14 Nov 2025
| 14 Nov 2025
How COVID-19 related policies reshaped organic aerosol source contributions in Central London
MRC Centre for Environment and Health, Environmental Research Group, Imperial College London, 86 Wood Lane, London, W12 0BZ, UK
Anja H. Tremper
MRC Centre for Environment and Health, Environmental Research Group, Imperial College London, 86 Wood Lane, London, W12 0BZ, UK
Max Priestman
MRC Centre for Environment and Health, Environmental Research Group, Imperial College London, 86 Wood Lane, London, W12 0BZ, UK
Anna Font
IMT Nord Europe, Europe, Institut Mines-Télécom, Univ. Lille, Centre for Education, Research and Innovation in Energy Environment (CERI EE), 59000 Lille, France
David C. Green
MRC Centre for Environment and Health, Environmental Research Group, Imperial College London, 86 Wood Lane, London, W12 0BZ, UK
HPRU in Environmental Exposures and Health, Imperial College London, 86 Wood Lane, London, W12 0BZ, UK
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A novel, advanced source apportionment technique was applied to a dataset measured in Magadino. Rolling positive matrix factorisation (PMF) allows for retrieving more realistic, time-dependent, and detailed information on organic aerosol sources. The strength of the rolling PMF mechanism is highlighted by comparing it with results derived from conventional seasonal PMF. Overall, this comprehensive interpretation of aerosol chemical speciation monitor data could be a role model for similar work.
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Francesco Canonaco, Anna Tobler, Gang Chen, Yulia Sosedova, Jay Gates Slowik, Carlo Bozzetti, Kaspar Rudolf Daellenbach, Imad El Haddad, Monica Crippa, Ru-Jin Huang, Markus Furger, Urs Baltensperger, and André Stephan Henry Prévôt
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Short summary
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Long-term ambient aerosol mass spectrometric data were analyzed with a statistical model (PMF) to obtain source contributions and fingerprints. The new aspects of this paper involve time-dependent source fingerprints by a rolling technique and the replacement of the full visual inspection of each run by a user-defined set of criteria to monitor the quality of each of these runs more efficiently. More reliable sources will finally provide better instruments for political mitigation strategies.
Cited articles
Aksoyoglu, S., Jiang, J., Ciarelli, G., Baltensperger, U., and Prévôt, A. S. H.: Role of ammonia in European air quality with changing land and ship emissions between 1990 and 2030, Atmos. Chem. Phys., 20, 15665–15680, https://doi.org/10.5194/acp-20-15665-2020, 2020.
Allan, J. D., Delia, A. E., Coe, H., Bower, K. N., Alfarra, M. R., Jimenez, J. L., Middlebrook, A. M., Drewnick, F., Onasch, T. B., Canagaratna, M. R., Jayne, J. T., and Worsnop, D. R.: A generalised method for the extraction of chemically resolved mass spectra from Aerodyne aerosol mass spectrometer data, J. Aerosol Sci., 35, 909–922, https://doi.org/10.1016/j.jaerosci.2004.02.007, 2004.
Bressi, M., Cavalli, F., Putaud, J. P., Fröhlich, R., Petit, J. E., Aas, W., Äijälä, M., Alastuey, A., Allan, J. D., Aurela, M., Berico, M., Bougiatioti, A., Bukowiecki, N., Canonaco, F., Crenn, V., Dusanter, S., Ehn, M., Elsasser, M., Flentje, H., Graf, P., Green, D. C., Heikkinen, L., Hermann, H., Holzinger, R., Hueglin, C., Keernik, H., Kiendler-Scharr, A., Kubelová, L., Lunder, C., Maasikmets, M., Makeš, O., Malaguti, A., Mihalopoulos, N., Nicolas, J. B., O'Dowd, C., Ovadnevaite, J., Petralia, E., Poulain, L., Priestman, M., Riffault, V., Ripoll, A., Schlag, P., Schwarz, J., Sciare, J., Slowik, J., Sosedova, Y., Stavroulas, I., Teinemaa, E., Via, M., Vodička, P., Williams, P. I., Wiedensohler, A., Young, D. E., Zhang, S., Favez, O., Minguillón, M. C., and Prevot, A. S. H.: A European aerosol phenomenology - 7: High-time resolution chemical characteristics of submicron particulate matter across Europe, Atmos. Environ. X, 10, 100108, https://doi.org/10.1016/J.AEAOA.2021.100108, 2021.
Canonaco, F., Tobler, A., Chen, G., Sosedova, Y., Slowik, J. G., Bozzetti, C., Daellenbach, K. R., El Haddad, I., Crippa, M., Huang, R.-J., Furger, M., Baltensperger, U., and Prévôt, A. S. H.: A new method for long-term source apportionment with time-dependent factor profiles and uncertainty assessment using SoFi Pro: application to 1 year of organic aerosol data, Atmos. Meas. Tech., 14, 923–943, https://doi.org/10.5194/amt-14-923-2021, 2021.
Carslaw, D.: deweather: Remove the influence of weather on air quality data, https://openair-project.github.io/deweather/ (last access: 23 September 2025), 2025.
Chebaicheb, H., de Brito, J. F., Amodeo, T., Couvidat, F., Petit, J.-E., Tison, E., Abbou, G., Baudic, A., Chatain, M., Chazeau, B., Marchand, N., Falhun, R., Francony, F., Ratier, C., Grenier, D., Vidaud, R., Zhang, S., Gille, G., Meunier, L., Marchand, C., Riffault, V., and Favez, O.: Multiyear high-temporal-resolution measurements of submicron aerosols at 13 French urban sites: data processing and chemical composition, Earth Syst. Sci. Data, 16, 5089–5109, https://doi.org/10.5194/essd-16-5089-2024, 2024.
Chen, G., Canonaco, F., Tobler, A., Aas, W., Alastuey, A., Allan, J., Atabakhsh, S., Aurela, M., Baltensperger, U., Bougiatioti, A., De Brito, J. F., Ceburnis, D., Chazeau, B., Chebaicheb, H., Daellenbach, K. R., Ehn, M., El Haddad, I., Eleftheriadis, K., Favez, O., Flentje, H., Font, A., Fossum, K., Freney, E., Gini, M., Green, D. C., Heikkinen, L., Herrmann, H., Kalogridis, A.-C., Keernik, H., Lhotka, R., Lin, C., Lunder, C., Maasikmets, M., Manousakas, M. I., Marchand, N., Marin, C., Marmureanu, L., Mihalopoulos, N., Močnik, G., Nęcki, J., O'Dowd, C., Ovadnevaite, J., Peter, T., Petit, J.-E., Pikridas, M., Matthew Platt, S., Pokorná, P., Poulain, L., Priestman, M., Riffault, V., Rinaldi, M., Różański, K., Schwarz, J., Sciare, J., Simon, L., Skiba, A., Slowik, J. G., Sosedova, Y., Stavroulas, I., Styszko, K., Teinemaa, E., Timonen, H., Tremper, A., Vasilescu, J., Via, M., Vodička, P., Wiedensohler, A., Zografou, O., Cruz Minguillón, M., and Prévôt, A. S. H.: European aerosol phenomenology −8: Harmonised source apportionment of organic aerosol using 22 Year-long ACSM/AMS datasets, Environ. Int., 166, 107325, https://doi.org/10.1016/j.envint.2022.107325, 2022.
Chen, G., Sosedova, Y., Canonaco, F., Fröhlich, R., Tobler, A., Vlachou, A., Daellenbach, K. R., Bozzetti, C., Hueglin, C., Graf, P., Baltensperger, U., Slowik, J. G., El Haddad, I., and Prévôt, A. S. H.: Time-dependent source apportionment of submicron organic aerosol for a rural site in an alpine valley using a rolling positive matrix factorisation (PMF) window, Atmos. Chem. Phys., 21, 15081–15101, https://doi.org/10.5194/acp-21-15081-2021, 2021.
Cliff, S. J., Drysdale, W., Lewis, A. C., Møller, S. J., Helfter, C., Metzger, S., Liddard, R., Nemitz, E., Barlow, J. F., and Lee, J. D.: Evidence of Heating-Dominated Urban NOx Emissions, Environ. Sci. Technol., 59, 4399–4408, https://doi.org/10.1021/acs.est.4c13276, 2025.
Crippa, M., DeCarlo, P. F., Slowik, J. G., Mohr, C., Heringa, M. F., Chirico, R., Poulain, L., Freutel, F., Sciare, J., Cozic, J., Di Marco, C. F., Elsasser, M., Nicolas, J. B., Marchand, N., Abidi, E., Wiedensohler, A., Drewnick, F., Schneider, J., Borrmann, S., Nemitz, E., Zimmermann, R., Jaffrezo, J.-L., Prévôt, A. S. H., and Baltensperger, U.: Wintertime aerosol chemical composition and source apportionment of the organic fraction in the metropolitan area of Paris, Atmos. Chem. Phys., 13, 961–981, https://doi.org/10.5194/acp-13-961-2013, 2013.
Defra: Use of domestic fuels in the hospitality sector – a qualitative review of hospitality businesses, Department for Environment, Food & Rural Affairs, https://sciencesearch.defra.gov.uk/ProjectDetails?ProjectId=21104 (last access: 22 October 2025), 2023.
Dominici, F., Peng, R. D., Bell, M. L., Pham, L., McDermott, A., Zeger, S. L., and Samet, J. M.: Fine Particulate Air Pollution and Hospital Admission for Cardiovascular and Respiratory Diseases, JAMA, 295, 1127, https://doi.org/10.1001/jama.295.10.1127, 2006.
European Environment Agency: Europe's air quality status 2024, European Environment Agency, https://doi.org/10.2800/5970, 2024.
European Union: Directive (EU) 2024/2881 of the European Parliament and of the Council of 23 October 2024 on ambient air quality and cleaner air for Europe (recast), The European Parliament and the Council of the European Union, http://data.europa.eu/eli/dir/2024/2881/oj (last access: 23 September 2025), 2024.
Font, A., Ciupek, K., Butterfield, D., and Fuller, G. W.: Long-term trends in particulate matter from wood burning in the United Kingdom: Dependence on weather and social factors, Environmental Pollution, 314, 120105, https://doi.org/10.1016/j.envpol.2022.120105, 2022.
Fröhlich, R., Cubison, M. J., Slowik, J. G., Bukowiecki, N., Prévôt, A. S. H., Baltensperger, U., Schneider, J., Kimmel, J. R., Gonin, M., Rohner, U., Worsnop, D. R., and Jayne, J. T.: The ToF-ACSM: a portable aerosol chemical speciation monitor with TOFMS detection, Atmos. Meas. Tech., 6, 3225–3241, https://doi.org/10.5194/amt-6-3225-2013, 2013.
Gamelas, C. A., Canha, N., Vicente, A., Silva, A., Borges, S., Alves, C., Kertesz, Z., and Almeida, S. M.: Source apportionment of PM2.5 before and after COVID-19 lockdown in an urban-industrial area of the Lisbon metropolitan area, Portugal, Urban Clim., 49, 101446, https://doi.org/10.1016/j.uclim.2023.101446, 2023.
Grange, S. K. and Carslaw, D. C.: Using meteorological normalisation to detect interventions in air quality time series, Science of The Total Environment, 653, 578–588, https://doi.org/10.1016/j.scitotenv.2018.10.344, 2019.
Grange, S. K., Carslaw, D. C., Lewis, A. C., Boleti, E., and Hueglin, C.: Random forest meteorological normalisation models for Swiss PM10 trend analysis, Atmos. Chem. Phys., 18, 6223–6239, https://doi.org/10.5194/acp-18-6223-2018, 2018.
Grange, S. K., Lee, J. D., Drysdale, W. S., Lewis, A. C., Hueglin, C., Emmenegger, L., and Carslaw, D. C.: COVID-19 lockdowns highlight a risk of increasing ozone pollution in European urban areas, Atmos. Chem. Phys., 21, 4169–4185, https://doi.org/10.5194/acp-21-4169-2021, 2021.
Hass-Mitchell, T., Joo, T., Rogers, M., Nault, B. A., Soong, C., Tran, M., Seo, M., Machesky, J. E., Canagaratna, M., Roscioli, J., Claflin, M. S., Lerner, B. M., Blomdahl, D. C., Misztal, P. K., Ng, N. L., Dillner, A. M., Bahreini, R., Russell, A., Krechmer, J. E., Lambe, A., and Gentner, D. R.: Increasing Contributions of Temperature-Dependent Oxygenated Organic Aerosol to Summertime Particulate Matter in New York City, ACS ES&T Air, 1, 113–128, https://doi.org/10.1021/acsestair.3c00037, 2024.
Hong Kong EPD: Control of Oily Fume and Cooking Odour from Restaurants and Food Business, Hong Kong Environmental Protection Department, https://www.epd.gov.hk/epd/sites/default/files/epd/english/environmentinhk/air/guide_ref/files/pamphlet_oilfume_eng.pdf (last access: 23 September 2025), 2024.
Hu, R., Wang, S., Zheng, H., Zhao, B., Liang, C., Chang, X., Jiang, Y., Yin, R., Jiang, J., and Hao, J.: Variations and Sources of Organic Aerosol in Winter Beijing under Markedly Reduced Anthropogenic Activities During COVID-2019, Environ. Sci. Technol., 56, 6956–6967, https://doi.org/10.1021/acs.est.1c05125, 2022.
IPCC: Climate Change 2021 – The Physical Science Basis, Cambridge University Press, https://doi.org/10.1017/9781009157896, 2021.
Jayne, J. T., Leard, D. C., Zhang, X., Davidovits, P., Smith, K. A., Kolb, C. E., and Worsnop, D. R.: Development of an Aerosol Mass Spectrometer for Size and Composition Analysis of Submicron Particles, Aerosol Science and Technology, 33, 49–70, https://doi.org/10.1080/027868200410840, 2000.
Jeong, C.-H., Yousif, M., and Evans, G. J.: Impact of the COVID-19 lockdown on the chemical composition and sources of urban PM2.5, Environmental Pollution, 292, 118417, https://doi.org/10.1016/j.envpol.2021.118417, 2022.
Joo, T., Rogers, M. J., Soong, C., Hass-Mitchell, T., Heo, S., Bell, M. L., Ng, N. L., and Gentner, D. R.: Aged and Obscured Wildfire Smoke Associated with Downwind Health Risks, Environ. Sci. Technol. Lett., 11, 1340–1347, https://doi.org/10.1021/acs.estlett.4c00785, 2024.
Kelly, F. J. and Fussell, J. C.: Size, source and chemical composition as determinants of toxicity attributable to ambient particulate matter, Atmos Environ, 60, 504–526, https://doi.org/10.1016/j.atmosenv.2012.06.039, 2012.
Krechmer, J., Lopez-Hilfiker, F., Koss, A., Hutterli, M., Stoermer, C., Deming, B., Kimmel, J., Warneke, C., Holzinger, R., Jayne, J., Worsnop, D., Fuhrer, K., Gonin, M., and de Gouw, J.: Evaluation of a New Reagent-Ion Source and Focusing Ion–Molecule Reactor for Use in Proton-Transfer-Reaction Mass Spectrometry, Anal. Chem., 90, 12011–12018, https://doi.org/10.1021/acs.analchem.8b02641, 2018.
Laj, P., Lund Myhre, C., Riffault, V., Amiridis, V., Fuchs, H., Eleftheriadis, K., Petäjä, T., Salameh, T., Kivekäs, N., Juurola, E., Saponaro, G., Philippin, S., Cornacchia, C., Alados Arboledas, L., Baars, H., Claude, A., De Mazière, M., Dils, B., Dufresne, M., Evangeliou, N., Favez, O., Fiebig, M., Haeffelin, M., Herrmann, H., Höhler, K., Illmann, N., Kreuter, A., Ludewig, E., Marinou, E., Möhler, O., Mona, L., Eder Murberg, L., Nicolae, D., Novelli, A., O'Connor, E., Ohneiser, K., Petracca Altieri, R. M., Picquet-Varrault, B., van Pinxteren, D., Pospichal, B., Putaud, J.-P., Reimann, S., Siomos, N., Stachlewska, I., Tillmann, R., Voudouri, K. A., Wandinger, U., Wiedensohler, A., Apituley, A., Comerón, A., Gysel-Beer, M., Mihalopoulos, N., Nikolova, N., Pietruczuk, A., Sauvage, S., Sciare, J., Skov, H., Svendby, T., Swietlicki, E., Tonev, D., Vaughan, G., Zdimal, V., Baltensperger, U., Doussin, J.-F., Kulmala, M., Pappalardo, G., Sorvari Sundet, S., and Vana, M.: Aerosol, Clouds and Trace Gases Research Infrastructure (ACTRIS): The European Research Infrastructure Supporting Atmospheric Science, B. Am. Meteorol. Soc., 105, E1098–E1136, https://doi.org/10.1175/BAMS-D-23-0064.1, 2024.
Lippmann, M., Chen, L. C., Gordon, T., Ito, K., and Thurston, G. D.: National Particle Component Toxicity (NPACT) Initiative: Integrated Epidemiologic and Toxicologic Studies of the Health Effects of Particulate Matter Components, Boston, Health Effects Institute, https://www.healtheffects.org/system/files/RR177-Lippmann.pdf (last access: 23 September 2025), 2013.
Liu, F., Joo, T., Ditto, J. C., Saavedra, M. G., Takeuchi, M., Boris, A. J., Yang, Y., Weber, R. J., Dillner, A. M., Gentner, D. R., and Ng, N. L.: Oxidized and Unsaturated: Key Organic Aerosol Traits Associated with Cellular Reactive Oxygen Species Production in the Southeastern United States, Environ. Sci. Technol., 57, 14150–14161, https://doi.org/10.1021/acs.est.3c03641, 2023.
Mebrahtu, T. F., McEachan, R. R. C., Yang, T. C., Crossley, K., Rashid, R., Hossain, R., Vaja, I., and Bryant, M.: Differences in public's perception of air quality and acceptability of a clean air zone: A mixed-methods cross sectional study, J. Transp. Health, 31, 101654, https://doi.org/10.1016/J.JTH.2023.101654, 2023.
Middlebrook, A. M., Bahreini, R., Jimenez, J. L., and Canagaratna, M. R.: Evaluation of Composition-Dependent Collection Efficiencies for the Aerodyne Aerosol Mass Spectrometer using Field Data, Aerosol Science and Technology, 46, 258–271, https://doi.org/10.1080/02786826.2011.620041, 2012.
Mohr, C., Huffman, J. A., Cubison, M. J., Aiken, A. C., Docherty, K. S., Kimmel, J. R., Ulbrich, I. M., Hannigan, M., and Jimenez, J. L.: Characterization of primary organic aerosol emissions from meat cooking, trash burning, and motor vehicles with high-resolution aerosol mass spectrometry and comparison with ambient and chamber observations, Environ. Sci. Technol., 43, 2443–2449, https://doi.org/10.1021/es8011518, 2009.
Mudway, I. S., Dundas, I., Wood, H. E., Marlin, N., Jamaludin, J. B., Bremner, S. A., Cross, L., Grieve, A., Nanzer, A., Barratt, B. M., Beevers, S., Dajnak, D., Fuller, G. W., Font, A., Colligan, G., Sheikh, A., Walton, R., Grigg, J., Kelly, F. J., Lee, T. H., and Griffiths, C. J.: Impact of London's low emission zone on air quality and children's respiratory health: a sequential annual cross-sectional study, Lancet Public Health, 4, e28–e40, https://doi.org/10.1016/S2468-2667(18)30202-0, 2019.
Ng, N. L., Herndon, S. C., Trimborn, A., Canagaratna, M. R., Croteau, P. L., Onasch, T. B., Sueper, D., Worsnop, D. R., Zhang, Q., Sun, Y. L., and Jayne, J. T.: An Aerosol Chemical Speciation Monitor (ACSM) for Routine Monitoring of the Composition and Mass Concentrations of Ambient Aerosol, Aerosol Science and Technology, 45, 780–794, https://doi.org/10.1080/02786826.2011.560211, 2011.
Oltra, C., Sala, R., López-asensio, S., Germán, S., and Boso, À.: Individual-Level Determinants of the Public Acceptance of Policy Measures to Improve Urban Air Quality: The Case of the Barcelona Low Emission Zone, Sustainability, 13, 1168, https://doi.org/10.3390/SU13031168, 2021.
ONS: GDP and events in history: how the COVID-19 pandemic shocked the UK economy, Office for National Statistics, https://www.ons.gov.uk/economy/grossdomesticproductgdp/articles/gdpandeventsinhistoryhowthecovid19pandemicshockedtheukeconomy/2022-05-24 (last access: 23 September 2025), 2022.
Petit, J.-E., Dupont, J.-C., Favez, O., Gros, V., Zhang, Y., Sciare, J., Simon, L., Truong, F., Bonnaire, N., Amodeo, T., Vautard, R., and Haeffelin, M.: Response of atmospheric composition to COVID-19 lockdown measures during spring in the Paris region (France), Atmos. Chem. Phys., 21, 17167–17183, https://doi.org/10.5194/acp-21-17167-2021, 2021.
Pinakidou, S.: People's perceptions of air pollution and their awareness of official indexes at the start of the twenty-first century: a review, Discover Environment, 3, 1–20, https://doi.org/10.1007/S44274-025-00213-X, 2025.
Pye, H. O. T., Ward-Caviness, C. K., Murphy, B. N., Appel, K. W., and Seltzer, K. M.: Secondary organic aerosol association with cardiorespiratory disease mortality in the United States, Nat. Commun., 12, 7215, https://doi.org/10.1038/s41467-021-27484-1, 2021.
Seinfeld, J. H., Wiley, J., and Pandis, S. N.: ATMOSPHERIC From Air Pollution to Climate Change SECOND EDITION, 628–674 pp., 2006.
Shi, Z., Song, C., Liu, B., Lu, G., Xu, J., Van Vu, T., Elliott, R. J. R., Li, W., Bloss, W. J., and Harrison, R. M.: Abrupt but smaller than expected changes in surface air quality attributable to COVID-19 lockdowns, Sci Adv, 7, 6696–6709, https://doi.org/10.1126/sciadv.abd6696, 2021.
Tian, J., Wang, Q., Zhang, Y., Yan, M., Liu, H., Zhang, N., Ran, W., and Cao, J.: Impacts of primary emissions and secondary aerosol formation on air pollution in an urban area of China during the COVID-19 lockdown, Environ. Int., 150, 106426, https://doi.org/10.1016/j.envint.2021.106426, 2021.
Tobler, A. K., Skiba, A., Wang, D. S., Croteau, P., Styszko, K., Nęcki, J., Baltensperger, U., Slowik, J. G., and Prévôt, A. S. H.: Improved chloride quantification in quadrupole aerosol chemical speciation monitors (Q-ACSMs), Atmos. Meas. Tech., 13, 5293–5301, https://doi.org/10.5194/amt-13-5293-2020, 2020.
Transport for London: Travel in London Report 13, Transport for London, https://content.tfl.gov.uk/travel-in-london-report-13.pdf (last access: 23 September 2025), 2020.
UK Health Security Agency (UKHSA): Statement on the differential toxicity of particulate matter according to source or constituents, https://www.gov.uk/government/publications/particulate-air-pollution-health-effects-of-exposure/statement-on-the-differential-toxicity-of-particulate-matter-according-to-source-or-constituents-2022 (last access: 23 September 2025), 27 July 2022.
Vasilakopoulou, C. N., Matrali, A., Skyllakou, K., Georgopoulou, M., Aktypis, A., Florou, K., Kaltsonoudis, C., Siouti, E., Kostenidou, E., Błaziak, A., Nenes, A., Papagiannis, S., Eleftheriadis, K., Patoulias, D., Kioutsioukis, I., and Pandis, S. N.: Rapid transformation of wildfire emissions to harmful background aerosol, NPJ Clim. Atmos. Sci., 6, 218, https://doi.org/10.1038/s41612-023-00544-7, 2023.
Via, M., Chen, G., Canonaco, F., Daellenbach, K. R., Chazeau, B., Chebaicheb, H., Jiang, J., Keernik, H., Lin, C., Marchand, N., Marin, C., O'Dowd, C., Ovadnevaite, J., Petit, J.-E., Pikridas, M., Riffault, V., Sciare, J., Slowik, J. G., Simon, L., Vasilescu, J., Zhang, Y., Favez, O., Prévôt, A. S. H., Alastuey, A., and Cruz Minguillón, M.: Rolling vs. seasonal PMF: real-world multi-site and synthetic dataset comparison, Atmos. Meas. Tech., 15, 5479–5495, https://doi.org/10.5194/amt-15-5479-2022, 2022.
Wei, Y., Qiu, X., Yazdi, M. D., Shtein, A., Shi, L., Yang, J., Peralta, A. A., Coull, B. A., and Schwartz, J. D.: The Impact of Exposure Measurement Error on the Estimated Concentration–Response Relationship between Long-Term Exposure to PM2.5 and Mortality, Environ. Health Perspect., 130, https://doi.org/10.1289/EHP10389, 2022.
Wei, Y., Feng, Y., Danesh Yazdi, M., Yin, K., Castro, E., Shtein, A., Qiu, X., Peralta, A. A., Coull, B. A., Dominici, F., and Schwartz, J. D.: Exposure-response associations between chronic exposure to fine particulate matter and risks of hospital admission for major cardiovascular diseases: population based cohort study, BMJ, e076939, https://doi.org/10.1136/bmj-2023-076939, 2024.
World Health Organization: WHO global air quality guidelines. Particulate matter (PM2.5 and PM10), ozone, nitrogen dioxide, sulfur dioxide and carbon monoxide, Geneva, World Health Organization, https://www.who.int/publications/i/item/9789240034228 (last access: 23 September 2025), 2021.
Wu, D., Zheng, H., Li, Q., Wang, S., Zhao, B., Jin, L., Lyu, R., Li, S., Liu, Y., Chen, X., Zhang, F., Wu, Q., Liu, T., Jiang, J., Wang, L., Li, X., Chen, J., and Hao, J.: Achieving health-oriented air pollution control requires integrating unequal toxicities of industrial particles, Nature Communications, 14, 1–12, https://doi.org/10.1038/s41467-023-42089-6, 2023.
Xu, J., Ge, X., Zhang, X., Zhao, W., Zhang, R., and Zhang, Y.: COVID-19 Impact on the Concentration and Composition of Submicron Particulate Matter in a Typical City of Northwest China, Geophys. Res. Lett., 47, https://doi.org/10.1029/2020GL089035, 2020.
Yao, X. and Zhang, L.: Identifying decadal trends in deweathered concentrations of criteria air pollutants in Canadian urban atmospheres with machine learning approaches, Atmos. Chem. Phys., 24, 7773–7791, https://doi.org/10.5194/acp-24-7773-2024, 2024.
Zhang, Q., Jimenez, J. L., Canagaratna, M. R., Allan, J. D., Coe, H., Ulbrich, I., Alfarra, M. R., Takami, A., Middlebrook, A. M., Sun, Y. L., Dzepina, K., Dunlea, E., Docherty, K., DeCarlo, P. F., Salcedo, D., Onasch, T., Jayne, J. T., Miyoshi, T., Shimono, A., Hatakeyama, S., Takegawa, N., Kondo, Y., Schneider, J., Drewnick, F., Borrmann, S., Weimer, S., Demerjian, K., Williams, P., Bower, K., Bahreini, R., Cottrell, L., Griffin, R. J., Rautiainen, J., Sun, J. Y., Zhang, Y. M., and Worsnop, D. R.: Ubiquity and dominance of oxygenated species in organic aerosols in anthropogenically-influenced Northern Hemisphere midlatitudes, Geophys. Res. Lett., 34, https://doi.org/10.1029/2007GL029979, 2007.
Short summary
This study quantified the impact of the COVID lockdown and the Eat Out To Help Out (EOTHO) on the sources/compositions of aerosols. The lockdown significantly reduced the primary emission sources. This study confirmed the important presence of cooking emissions from commercial kitchens in Central London by detecting the enhancement caused by the EOTHO policy after the lockdown. Biomass burning organic aerosol co-emitted with cooking activities from either the fuels or food ingredients used.
This study quantified the impact of the COVID lockdown and the Eat Out To Help Out (EOTHO) on...
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