{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,14]],"date-time":"2026-02-14T02:52:46Z","timestamp":1771037566396,"version":"3.50.1"},"reference-count":46,"publisher":"MDPI AG","issue":"21","license":[{"start":{"date-parts":[[2023,11,5]],"date-time":"2023-11-05T00:00:00Z","timestamp":1699142400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100000001","name":"National Science Foundation","doi-asserted-by":"publisher","award":["1737633"],"award-info":[{"award-number":["1737633"]}],"id":[{"id":"10.13039\/100000001","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Low-cost, long-term measures of air pollution concentrations are often needed for epidemiological studies and policy analyses of household air pollution. The Washington passive sampler (WPS), an ultra-low-cost method for measuring the long-term average levels of light-absorbing carbon (LAC) air pollution, uses digital images to measure the changes in the reflectance of a passively exposed paper filter. A prior publication on WPS reported high precision and reproducibility. Here, we deployed three methods to each of 10 households in Ulaanbaatar, Mongolia: one PurpleAir for PM2.5; two ultrasonic personal aerosol samplers (UPAS) with quartz filters for the thermal-optical analysis of elemental carbon (EC); and two WPS for LAC. We compared multiple rounds of 4-week-average measurements. The analyses calibrating the LAC to the elemental carbon measurement suggest that 1 \u00b5g of EC\/m3 corresponds to 62 PI\/month (R2 = 0.83). The EC-LAC calibration curve indicates an accuracy (root-mean-square error) of 3.1 \u00b5g of EC\/m3, or ~21% of the average elemental carbon concentration. The RMSE values observed here for the WPS are comparable to the reported accuracy levels for other methods, including reference methods. Based on the precision and accuracy results shown here, as well as the increased simplicity of deployment, the WPS may merit further consideration for studying air quality in homes that use solid fuels.<\/jats:p>","DOI":"10.3390\/s23218977","type":"journal-article","created":{"date-parts":[[2023,11,5]],"date-time":"2023-11-05T07:35:06Z","timestamp":1699169706000},"page":"8977","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Application of an Ultra-Low-Cost Passive Sampler for Light-Absorbing Carbon in Mongolia"],"prefix":"10.3390","volume":"23","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-1918-8464","authenticated-orcid":false,"given":"Bujin","family":"Bekbulat","sequence":"first","affiliation":[{"name":"Department of Civil and Environmental Engineering, University of Washington, Seattle, WA 98195, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4298-7854","authenticated-orcid":false,"given":"Pratyush","family":"Agrawal","sequence":"additional","affiliation":[{"name":"Center for Study of Science, Technology & Policy, Bengaluru 560095, Karnataka, India"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ryan W.","family":"Allen","sequence":"additional","affiliation":[{"name":"Department of Health Sciences, Simon Fraser University, Burnaby, BC V5A 1S6, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Michael","family":"Baum","sequence":"additional","affiliation":[{"name":"Axon Engineering LLC, Bellevue, WA 98006, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Buyantushig","family":"Boldbaatar","sequence":"additional","affiliation":[{"name":"School of Public Health, Mongolian National University of Medical Sciences, Ulaanbaatar 14210, Mongolia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Lara P.","family":"Clark","sequence":"additional","affiliation":[{"name":"Department of Civil and Environmental Engineering, University of Washington, Seattle, WA 98195, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2566-1094","authenticated-orcid":false,"given":"Jargalsaikhan","family":"Galsuren","sequence":"additional","affiliation":[{"name":"School of Public Health, Mongolian National University of Medical Sciences, Ulaanbaatar 14210, Mongolia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Perry","family":"Hystad","sequence":"additional","affiliation":[{"name":"Department of Public Health and Human Sciences, Oregon State University, Corvallis, OR 97331, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Christian","family":"L\u2019Orange","sequence":"additional","affiliation":[{"name":"Department of Mechanical Engineering, Colorado State University, Fort Collins, CO 80523, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0400-6584","authenticated-orcid":false,"given":"Sreekanth","family":"Vakacherla","sequence":"additional","affiliation":[{"name":"Center for Study of Science, Technology & Policy, Bengaluru 560095, Karnataka, India"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"John","family":"Volckens","sequence":"additional","affiliation":[{"name":"Department of Mechanical Engineering, Colorado State University, Fort Collins, CO 80523, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4087-1209","authenticated-orcid":false,"given":"Julian D.","family":"Marshall","sequence":"additional","affiliation":[{"name":"Department of Civil and Environmental Engineering, University of Washington, Seattle, WA 98195, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2023,11,5]]},"reference":[{"key":"ref_1","unstructured":"World Health Organization (2021, December 28). 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