{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T02:31:11Z","timestamp":1760236271999,"version":"build-2065373602"},"reference-count":52,"publisher":"MDPI AG","issue":"22","license":[{"start":{"date-parts":[[2021,11,15]],"date-time":"2021-11-15T00:00:00Z","timestamp":1636934400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100002848","name":"Agencia Nacional de Investigaci\u00f3n y Desarrollo","doi-asserted-by":"publisher","award":["CONICYT-PFCHA\/ Mag\u00edsterNacional\/ 2018 \u2013 2218120"],"award-info":[{"award-number":["CONICYT-PFCHA\/ Mag\u00edsterNacional\/ 2018 \u2013 2218120"]}],"id":[{"id":"10.13039\/501100002848","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>We propose a monochromatic low-cost automatic sun photometer (LoCo-ASP) to perform distributed aerosol optical depth (AOD) measurements at the city scale. This kind of network could fill the gap between current automatic ground instruments\u2014with good temporal resolution and accuracy, but few devices per city and satellite products\u2014with global coverage, but lower temporal resolution and accuracy-. As a first approach, we consider a single equivalent wavelength around 408 nm. The cost of materials for the instrument is around 220 dollars. Moreover, we propose a calibration transfer for a pattern instrument, and estimate the uncertainties for several units and due to the internal differences and the calibration process. We achieve a max MAE of 0.026 for 38 sensors at 408 nm compared with AERONET Cimel; a mean standard deviation of 0.0062 among our entire sensor for measurement and a calibration uncertainty of 0.01. Finally, we perform city-scale measurements to show the dynamics of AOD. Our instrument can measure unsupervised, with an expected error for AOD between 0.02 and 0.03.<\/jats:p>","DOI":"10.3390\/rs13224585","type":"journal-article","created":{"date-parts":[[2021,11,15]],"date-time":"2021-11-15T20:46:47Z","timestamp":1637009207000},"page":"4585","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Automated Low-Cost LED-Based Sun Photometer for City Scale Distributed Measurements"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-3201-7363","authenticated-orcid":false,"given":"Cristobal","family":"Garrido","sequence":"first","affiliation":[{"name":"Space and Planetary Exploration Laboratory (SPEL), Faculty of Physical and Mathematical Sciences, University of Chile, Santiago 8370448, Chile"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6504-6657","authenticated-orcid":false,"given":"Felipe","family":"Toledo","sequence":"additional","affiliation":[{"name":"Laboratoire de M\u00e9t\u00e9orologie Dynamique, Institut Pierre Simon Laplace, Ecole polytechnique-IP Paris, ENS-PSL Universit\u00e9, Sorbonne Universit\u00e9, CNRS, 91128 Palaiseau, France"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7701-5839","authenticated-orcid":false,"given":"Marcos","family":"Diaz","sequence":"additional","affiliation":[{"name":"Space and Planetary Exploration Laboratory (SPEL), Faculty of Physical and Mathematical Sciences, University of Chile, Santiago 8370448, Chile"},{"name":"Electrical Enginering Department, Faculty of Physical and Mathematical Sciences, University of Chile, Santiago 8370451, Chile"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7440-7810","authenticated-orcid":false,"given":"Roberto","family":"Rondanelli","sequence":"additional","affiliation":[{"name":"Space and Planetary Exploration Laboratory (SPEL), Faculty of Physical and Mathematical Sciences, University of Chile, Santiago 8370448, Chile"},{"name":"Department of Geophysics, Faculty of Physical and Mathematical Sciences, University of Chile, Santiago 8370449, Chile"},{"name":"Center for Climate and Resilience Research, University of Chile, Santiago 8370449, Chile"}]}],"member":"1968","published-online":{"date-parts":[[2021,11,15]]},"reference":[{"key":"ref_1","unstructured":"Wallace, J.M., and Hobbs, P.V. (2006). Atmospheric Science: An Introductory Survey, Elsevier."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"3803","DOI":"10.1021\/acs.chemrev.5b00067","article-title":"Formation of urban fine particulate matter","volume":"115","author":"Zhang","year":"2015","journal-title":"Chem. Rev."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1059","DOI":"10.1175\/BAMS-88-7-1059","article-title":"Aerosol properties and processes: A path from field and laboratory measurements to global climate models","volume":"88","author":"Ghan","year":"2007","journal-title":"Bull. Am. Meteorol. Soc."},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Kim, D., and Ramanathan, V. (2008). Solar radiation budget and radiative forcing due to aerosols and clouds. J. Geophys. Res. Atmos., 113.","DOI":"10.1029\/2007JD008434"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"4011","DOI":"10.5194\/acp-9-4011-2009","article-title":"Taklimakan dust aerosol radiative heating derived from CALIPSO observations using the Fu-Liou radiation model with CERES constraints","volume":"9","author":"Huang","year":"2009","journal-title":"Atmos. Chem. Phys."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"713","DOI":"10.1038\/nclimate1528","article-title":"Stratospheric aerosol particles and solar-radiation management","volume":"2","author":"Pope","year":"2012","journal-title":"Nat. Clim. Chang."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Dayou, J., Chang, J.H.W., and Sentian, J. (2014). Ground-Based Aerosol Optical Depth Measurement Using Sunphotometers, Springer.","DOI":"10.1007\/978-981-287-101-5"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"2205","DOI":"10.1016\/S1352-2310(97)00054-X","article-title":"A study of the ability of pure secondary organic aerosol to act as cloud condensation nuclei","volume":"31","author":"Cruz","year":"1997","journal-title":"Atmos. Environ."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"VanReken, T.M., Rissman, T.A., Roberts, G.C., Varutbangkul, V., Jonsson, H.H., Flagan, R.C., and Seinfeld, J.H. (2003). Toward aerosol\/cloud condensation nuclei (CCN) closure during CRYSTAL-FACE. J. Geophys. Res. Atmos., 108.","DOI":"10.1029\/2003JD003582"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"24497","DOI":"10.1038\/srep24497","article-title":"Characterization and parameterization of aerosol cloud condensation nuclei activation under different pollution conditions","volume":"6","author":"Che","year":"2016","journal-title":"Sci. Rep."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Li, Z., Rosenfeld, D., and Fan, J. (2017). Aerosols and their impact on radiation, clouds, precipitation, and severe weather events, Oxford Research Encyclopedia of Environmental Science.","DOI":"10.1093\/acrefore\/9780199389414.013.126"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1233","DOI":"10.1016\/S0140-6736(02)11274-8","article-title":"Air pollution and health","volume":"360","author":"Brunekreef","year":"2002","journal-title":"Lancet"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"2803","DOI":"10.1016\/j.atmosenv.2004.02.034","article-title":"Aerosol modeling with CHIMERE\u2014preliminary evaluation at the continental scale","volume":"38","author":"Bessagnet","year":"2004","journal-title":"Atmos. Environ."},{"key":"ref_14","first-page":"7","article-title":"Aerosols and their relation to global climate and climate sensitivity","volume":"4","author":"Myhre","year":"2013","journal-title":"Nat. Educ. Knowl."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"891","DOI":"10.5194\/amt-5-891-2012","article-title":"Tracking of urban aerosols using combined LIDAR-based remote sensing and ground-based measurements","volume":"5","author":"He","year":"2012","journal-title":"Atmos. Meas. Tech."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1113","DOI":"10.1002\/2017JD027309","article-title":"AOT Retrieval Procedure for Distributed Measurements With Low-Cost Sun Photometers","volume":"123","author":"Toledo","year":"2018","journal-title":"J. Geophys. Res. Atmos."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"4681","DOI":"10.5194\/acp-20-4681-2020","article-title":"Soccer games and record-breaking PM 2.5 pollution events in Santiago, Chile","volume":"20","author":"Lapere","year":"2020","journal-title":"Atmos. Chem. Phys."},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Lapere, R., Mailler, S., and Menut, L. (2021). The 2017 Mega-Fires in Central Chile: Impacts on Regional Atmospheric Composition and Meteorology Assessed from Satellite Data and Chemistry-Transport Modeling. Atmosphere, 12.","DOI":"10.3390\/atmos12030344"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"4941","DOI":"10.1364\/AO.35.004941","article-title":"Tropospheric aerosol extinction coefficient profiles derived from scanning lidar measurements over Tsukuba, Japan, from 1990 to 1993","volume":"35","author":"Sasano","year":"1996","journal-title":"Appl. Opt."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/S0034-4257(98)00031-5","article-title":"AERONET\u2014A federated instrument network and data archive for aerosol characterization","volume":"66","author":"Holben","year":"1998","journal-title":"Remote Sens. Environ."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"655","DOI":"10.5194\/acp-18-655-2018","article-title":"An overview of mesoscale aerosol processes, comparisons, and validation studies from DRAGON networks","volume":"18","author":"Holben","year":"2018","journal-title":"Atmos. Chem. Phys."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"442","DOI":"10.1109\/TGRS.2002.808226","article-title":"Cloud and aerosol properties, precipitable water, and profiles of temperature and water vapor from MODIS","volume":"41","author":"King","year":"2003","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"5741","DOI":"10.5194\/amt-11-5741-2018","article-title":"MODIS collection 6 MAIAC algorithm","volume":"11","author":"Lyapustin","year":"2018","journal-title":"Atmos. Meas. Tech."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"925","DOI":"10.5194\/amt-11-925-2018","article-title":"Collocation mismatch uncertainties in satellite aerosol retrieval validation","volume":"11","author":"Virtanen","year":"2018","journal-title":"Atmos. Meas. Tech."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"10066","DOI":"10.1038\/s41598-018-28417-7","article-title":"Comparison of AOD from CALIPSO, MODIS, and sun photometer under different conditions over central China","volume":"8","author":"Liu","year":"2018","journal-title":"Sci. Rep."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"5955","DOI":"10.5194\/amt-13-5955-2020","article-title":"Improving GOES Advanced Baseline Imager (ABI) aerosol optical depth (AOD) retrievals using an empirical bias correction algorithm","volume":"13","author":"Zhang","year":"2020","journal-title":"Atmos. Meas. Tech."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"879","DOI":"10.1016\/j.scitotenv.2019.07.326","article-title":"Evaluation and uncertainty estimate of next-generation geostationary meteorological Himawari-8\/AHI aerosol products","volume":"692","author":"Wei","year":"2019","journal-title":"Sci. Total Environ."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"596","DOI":"10.4209\/aaqr.2013.03.0082","article-title":"Satellite retrievals of aerosol optical depth over a subtropical urban area: The role of stratification and surface reflectance","volume":"14","author":"Escribano","year":"2014","journal-title":"Aerosol Air Qual. Res."},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Boersma, K., and De Vroom, J. (2006). Validation of MODIS aerosol observations over the Netherlands with GLOBE student measurements. J. Geophys. Res. Atmos., 111.","DOI":"10.1029\/2006JD007172"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"5467","DOI":"10.5194\/acp-7-5467-2007","article-title":"Analysis of Visible\/SWIR surface reflectance ratios for aerosol retrievals from satellite in Mexico City urban area","volume":"7","author":"Prinn","year":"2007","journal-title":"Atmos. Chem. Phys."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"1137","DOI":"10.1016\/j.renene.2019.10.005","article-title":"Significant decrease of photovoltaic power production by aerosols. The case of Santiago de Chile","volume":"148","author":"Rondanelli","year":"2020","journal-title":"Renew. Energy"},{"key":"ref_32","first-page":"97","article-title":"Air pollution and mortality: Results from a study of Santiago, Chile","volume":"6","author":"Ostro","year":"1996","journal-title":"J. Expo. Anal. Environ. Epidemiol."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"4195","DOI":"10.5194\/amt-13-4195-2020","article-title":"An overview of and issues with sky radiometer technology and SKYNET","volume":"13","author":"Nakajima","year":"2020","journal-title":"Atmos. Meas. Tech."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"14573","DOI":"10.1029\/2001JD900103","article-title":"Design, calibration, and performance of MICROTOPS II handheld ozone monitor and Sun photometer","volume":"106","author":"Morys","year":"2001","journal-title":"J. Geophys. Res. Atmos."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"4733","DOI":"10.1029\/2000JD900545","article-title":"Development of an inexpensive handheld LED-based Sun photometer for the GLOBE program","volume":"106","author":"Brooks","year":"2001","journal-title":"J. Geophys. Res. Atmos."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"631","DOI":"10.5194\/amt-9-631-2016","article-title":"The new sun-sky-lunar Cimel CE318-T multiband photometer\u2014A comprehensive performance evaluation","volume":"9","author":"Barreto","year":"2016","journal-title":"Atmos. Meas. Tech."},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Brooks, D.R. (2008). Bringing the Sun Down to Earth: Designing Inexpensive Instruments for Monitoring the Atmosphere, Springer Science & Business Media.","DOI":"10.1007\/978-1-4020-8694-6"},{"key":"ref_38","unstructured":"Seinfeld, J.H., and Pandis, S.N. (2016). Atmospheric Chemistry and Physics: From Air Pollution to Climate Change, John Wiley & Sons."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"1108","DOI":"10.1364\/AO.33.001108","article-title":"Air mass and refraction","volume":"33","author":"Young","year":"1994","journal-title":"Appl. Opt."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"577","DOI":"10.1016\/j.solener.2003.12.003","article-title":"Solar position algorithm for solar radiation applications","volume":"76","author":"Reda","year":"2004","journal-title":"Sol. Energy"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"2765","DOI":"10.1364\/AO.34.002765","article-title":"Rayleigh-scattering calculations for the terrestrial atmosphere","volume":"34","author":"Bucholtz","year":"1995","journal-title":"Appl. Opt."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"14555","DOI":"10.5194\/acp-18-14555-2018","article-title":"Assessment of Sun photometer Langley calibration at the high-elevation sites Mauna Loa and Iza\u00f1a","volume":"18","author":"Toledano","year":"2018","journal-title":"Atmos. Chem. Phys."},{"key":"ref_43","first-page":"156","article-title":"On the atmospheric transmission of sun radiation and on dust in the air","volume":"11","year":"1929","journal-title":"Geogr. Ann."},{"key":"ref_44","doi-asserted-by":"crossref","unstructured":"Schuster, G.L., Dubovik, O., and Holben, B.N. (2006). Angstrom exponent and bimodal aerosol size distributions. J. Geophys. Res. Atmos., 111.","DOI":"10.1029\/2005JD006328"},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"2570","DOI":"10.1016\/j.egypro.2014.11.279","article-title":"Detection of H2S, SO2 and NO2 in CO2 at pressures ranging from 1-40 bar by using broadband absorption spectroscopy in the UV\/VIS range","volume":"63","author":"Gersen","year":"2014","journal-title":"Energy Procedia"},{"key":"ref_46","unstructured":"Mobley, C.D., Werdell, J., Franz, B., Ahmad, Z., and Bailey, S. (2021, October 20). Atmospheric Correction for sAtellite Ocean Color Radiometry. Available online: https:\/\/www.researchgate.net\/publication\/321536667_Atmospheric_Correction_for_Satellite_Ocean_Color_Radiometry."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"6504","DOI":"10.1364\/AO.46.006504","article-title":"Atmospheric correction for NO2 absorption in retrieving water-leaving reflectances from the SeaWiFS and MODIS measurements","volume":"46","author":"Ahmad","year":"2007","journal-title":"Appl. Opt."},{"key":"ref_48","unstructured":"Van Geffen, J., Eskes, H., Boersma, K., Maasakkers, J., and Veefkind, J. (2021, October 20). TROPOMI ATBD of the Total and Tropospheric NO2 Data Products, Report S5P-KNMI-L2-0005-RP, 21AD. Available online: https:\/\/sentinel.esa.int\/documents\/247904\/2476257\/Sentinel-5P-TROPOMI-ATBD-NO2-data-products."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"2035","DOI":"10.1016\/j.atmosenv.2004.12.033","article-title":"Modelling of air pollution dispersion in Santiago de Chile","volume":"39","author":"Schmitz","year":"2005","journal-title":"Atmos. Environ."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"118124","DOI":"10.1016\/j.envpol.2021.118124","article-title":"Deep winter intrusions of urban black carbon into a canyon near Santiago, Chile: A pathway towards Andean glaciers","volume":"291","author":"Huneeus","year":"2021","journal-title":"Environ. Pollut."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"5431","DOI":"10.5194\/amt-12-5431-2019","article-title":"A low-cost monitor for simultaneous measurement of fine particulate matter and aerosol optical depth\u2013Part 1: Specifications and testing","volume":"12","author":"Wendt","year":"2019","journal-title":"Atmos. Meas. Tech."},{"key":"ref_52","first-page":"12781","article-title":"Some considerations about \u00c5ngstr\u00f6m exponent distributions","volume":"7","author":"Wagner","year":"2007","journal-title":"Atmos. Chem. Phys. Discuss."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/13\/22\/4585\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T07:30:25Z","timestamp":1760167825000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/13\/22\/4585"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,11,15]]},"references-count":52,"journal-issue":{"issue":"22","published-online":{"date-parts":[[2021,11]]}},"alternative-id":["rs13224585"],"URL":"https:\/\/doi.org\/10.3390\/rs13224585","relation":{},"ISSN":["2072-4292"],"issn-type":[{"type":"electronic","value":"2072-4292"}],"subject":[],"published":{"date-parts":[[2021,11,15]]}}}