{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,5]],"date-time":"2026-02-05T05:16:33Z","timestamp":1770268593611,"version":"3.49.0"},"reference-count":86,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2021,1,3]],"date-time":"2021-01-03T00:00:00Z","timestamp":1609632000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>This paper analyzes 12 years of tropospheric ozone (O3) concentration measurements using robust techniques. The measurements were taken at an air quality monitoring station called Belisario, which is in Quito, Ecuador; the data collection time period was 1 January 2008 to 31 December 2019, and the measurements were carried out using photometric O3 analyzers. Here, the measurement results were used to build variables that represented hours, days, months, and years, and were then classified and categorized. The index of air quality (IAQ) of the city was used to make the classifications, and robust and nonrobust confidence intervals were used to make the categorizations. Furthermore, robust analysis methods were compared with classical methods, nonparametric methods, and bootstrap-based methods. The results showed that the analysis using robust methods is better than the analysis using nonrobust methods, which are not immune to the influence of extreme observations. Using all of the aforementioned methods, confidence intervals were used to both establish and quantify differences between categories of the groups of variables under study. In addition, the central tendency and variability of the O3 concentration at Belisario station were exhaustively analyzed, concluding that said concentration was stable for years, highly variable for months and hours, and slightly changing between the days of the week. Additionally, according to the criteria established by the IAQ, it was shown that in Quito, the O3 concentration levels during the study period were not harmful to human health.<\/jats:p>","DOI":"10.3390\/s21010277","type":"journal-article","created":{"date-parts":[[2021,1,3]],"date-time":"2021-01-03T19:54:46Z","timestamp":1609703686000},"page":"277","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":7,"title":["Robust Inferential Techniques Applied to the Analysis of the Tropospheric Ozone Concentration in an Urban Area"],"prefix":"10.3390","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4643-8377","authenticated-orcid":false,"given":"Wilmar","family":"Hernandez","sequence":"first","affiliation":[{"name":"Facultad de Ingenier\u00eda y Ciencias Aplicadas, Universidad de Las Am\u00e9ricas, Quito EC-170125, Ecuador"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9732-2131","authenticated-orcid":false,"given":"Alfredo","family":"Mendez","sequence":"additional","affiliation":[{"name":"Departamento de Matematica Aplicada a las Tecnolog\u00edas de la Informacion y las Comunicaciones, ETS de Ingenier\u00eda y Sistemas de Telecomunicacion, Universidad Politecnica de Madrid, 28031 Madrid, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Vicente","family":"Gonz\u00e1lez-Posadas","sequence":"additional","affiliation":[{"name":"Departamento de Teor\u00eda de la Se\u00f1al y Comunicaciones, ETS de Ingenieria y Sistemas de Telecomunicacion, Universidad Politecnica de Madrid, 28031 Madrid, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jos\u00e9 Luis","family":"Jim\u00e9nez-Mart\u00edn","sequence":"additional","affiliation":[{"name":"Departamento de Teor\u00eda de la Se\u00f1al y Comunicaciones, ETS de Ingenieria y Sistemas de Telecomunicacion, Universidad Politecnica de Madrid, 28031 Madrid, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Iv\u00e1n Menes","family":"Camejo","sequence":"additional","affiliation":[{"name":"Facultad de Informatica y Electronica, Escuela Superior Politecnica de Chimborazo, Riobamba EC-060155, Ecuador"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2021,1,3]]},"reference":[{"key":"ref_1","unstructured":"U.S. Environmental Protection Agency (2020, November 01). 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