{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,20]],"date-time":"2026-03-20T05:16:13Z","timestamp":1773983773762,"version":"3.50.1"},"reference-count":39,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2025,2,8]],"date-time":"2025-02-08T00:00:00Z","timestamp":1738972800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100019370","name":"national funds through FCT\/MCTES (PIDDAC): LEPABE","doi-asserted-by":"publisher","award":["UIDP\/00511\/2020"],"award-info":[{"award-number":["UIDP\/00511\/2020"]}],"id":[{"id":"10.13039\/501100019370","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100019370","name":"national funds through FCT\/MCTES (PIDDAC): LEPABE","doi-asserted-by":"publisher","award":["UIDB\/00511\/2020"],"award-info":[{"award-number":["UIDB\/00511\/2020"]}],"id":[{"id":"10.13039\/501100019370","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100019370","name":"national funds through FCT\/MCTES (PIDDAC): LEPABE","doi-asserted-by":"publisher","award":["LA\/P\/0045\/2020"],"award-info":[{"award-number":["LA\/P\/0045\/2020"]}],"id":[{"id":"10.13039\/501100019370","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100019370","name":"ALiCE","doi-asserted-by":"publisher","award":["UIDP\/00511\/2020"],"award-info":[{"award-number":["UIDP\/00511\/2020"]}],"id":[{"id":"10.13039\/501100019370","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100019370","name":"ALiCE","doi-asserted-by":"publisher","award":["UIDB\/00511\/2020"],"award-info":[{"award-number":["UIDB\/00511\/2020"]}],"id":[{"id":"10.13039\/501100019370","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100019370","name":"ALiCE","doi-asserted-by":"publisher","award":["LA\/P\/0045\/2020"],"award-info":[{"award-number":["LA\/P\/0045\/2020"]}],"id":[{"id":"10.13039\/501100019370","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sustainability"],"abstract":"<jats:p>This paper aims to assess the temporal and spatial variability of particulate matter (PM) concentrations (PM2.5 and PM10) at several rural and urban monitoring sites located in Portugal between 2011 and 2022. The exceedances to European Union Directive limits and World Health Organization (WHO) air quality guidelines were also evaluated. Higher PM concentrations were observed mainly at urban sites (e.g., up to 156 exceedances of the WHO PM2.5 guideline for daily average concentrations were recorded in a year), with the main contributions being from traffic emissions and industrial activities. On the other hand, the lower number of exceedances at rural sites can be attributed to long-range transport (e.g., Saharan dust) and wildfires. Temporal trends showed that PM2.5 concentrations decreased by up to 0.6 \u00b5g\/m3 per year, while PM10 reductions reached 1.0 \u00b5g\/m3 per year at certain sites, showing the effectiveness of air quality policies and clean technology advancements. Also, the number of exceedances of the air quality guideline of WHO for PM2.5 at urban traffic sites like Entrecampos decreased from 140 in 2015 to 15 in 2022. Principal component analysis grouped the air monitoring sites based on PM variability. These findings provide a comprehensive understanding of the temporal variation of PM concentration, contributing to air quality management strategies and the design of mitigation measures.<\/jats:p>","DOI":"10.3390\/su17041402","type":"journal-article","created":{"date-parts":[[2025,2,10]],"date-time":"2025-02-10T03:39:47Z","timestamp":1739158787000},"page":"1402","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Patterns and Dynamics of PM2.5 and PM10 Across Portugal: A Twelve-Year Perspective"],"prefix":"10.3390","volume":"17","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2738-5102","authenticated-orcid":false,"given":"Jos\u00e9 C. M.","family":"Pires","sequence":"first","affiliation":[{"name":"LEPABE\u2014Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal"},{"name":"ALiCE\u2014Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2025,2,8]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"107423","DOI":"10.1016\/j.atmosres.2024.107423","article-title":"Characterization of cross-continental PM2.5: Insights into emissions and chemical composition","volume":"305","author":"Scaramboni","year":"2024","journal-title":"Atmos. 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