{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,22]],"date-time":"2026-10-22T13:04:35Z","timestamp":1792674275999,"version":"4.5.0"},"reference-count":62,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2025,7,24]],"date-time":"2025-07-24T00:00:00Z","timestamp":1753315200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001843","name":"Science and Engineering Research Board","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100001843","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Public Health"],"abstract":"<jats:p>Indoor air quality plays a crucial role in the health and well-being of residents. Delhi, known as one of the most polluted cities globally, often receives insufficient attention in managing and mitigating related health impacts. This study isolated, characterized, and assessed microbial indoor air quality (bioaerosols) using multiproxy approaches and correlated findings with associated health effects. The spatial variation of bacterial aerosols showed irregular patterns, increasing from winter to summer and decreasing in fall; fungal aerosols consistently increased from winter to fall. Bacterial aerosol concentrations ranged from 730 to 5,300\u202fCFU\/m<jats:sup>3<\/jats:sup>, while fungal concentrations were between 1,330 and 6,050\u202fCFU\/m<jats:sup>3<\/jats:sup>, significantly exceeding the recommended limits. The size distribution of fungal aerosols varied across seasons, with higher concentrations in the 4th and 5th stages of the sampler. Several airborne bacterial and fungal genera, including <jats:italic>Staphylococcus<\/jats:italic>, <jats:italic>Streptococcus<\/jats:italic>, <jats:italic>Micrococcus<\/jats:italic>, <jats:italic>Aspergillus<\/jats:italic>, <jats:italic>Penicillium<\/jats:italic>, and <jats:italic>Cladosporium<\/jats:italic>, were identified in homes. Health effects were most pronounced in winter followed by fall, with symptoms such as headaches, eye irritation, allergic rhinitis, coughing, and sneezing being common. As per this study, there may be a correlation between indoor bioaerosol concentrations, seasonal variations, and health outcomes, though further in-depth <jats:italic>in vitro<\/jats:italic>, exposure assessment, and epidemiological studies are necessary to substantiate these findings.<\/jats:p>","DOI":"10.3389\/fpubh.2025.1626827","type":"journal-article","created":{"date-parts":[[2025,7,24]],"date-time":"2025-07-24T05:34:42Z","timestamp":1753335282000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":5,"title":["Microbial indoor air pollution in Delhi Metropolitan City is attributable to severe respiratory and general health effects among residents"],"prefix":"10.3389","volume":"13","author":[{"given":"Pradeep","family":"Kumar","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rajeev","family":"Singh","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2025,7,24]]},"reference":[{"key":"ref1","doi-asserted-by":"publisher","first-page":"434","DOI":"10.1097\/ACI.0000000000000301","article-title":"Climate change, air pollution, and allergic respiratory diseases: an update","volume":"16","author":"D\u2019Amato","year":"2016","journal-title":"Curr Opin Allergy Clin Immunol"},{"key":"ref2","doi-asserted-by":"publisher","first-page":"191","DOI":"10.1136\/oemed-2011-100310","article-title":"A case\u2013cohort study of lung cancer in poultry and control workers: occupational findings","volume":"69","author":"Felini","year":"2012","journal-title":"Occup Environ Med"},{"key":"ref3","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1007\/s10453-021-09718-3","article-title":"Seasonal variation and size distribution in the airborne indoor microbial concentration of residential houses in Delhi and its impact on health","volume":"37","author":"Kumar","year":"2021","journal-title":"Aerobiologia"},{"key":"ref4","article-title":"Occupational and environmental exposure to bioaerosols from composts and potential health effects: a critical review of published data","volume-title":"Health and Safety Executive (HSE) research report","author":"Swan","year":"2003"},{"key":"ref5","doi-asserted-by":"publisher","first-page":"861","DOI":"10.1038\/nri2871","article-title":"Farm living: effects on childhood asthma and allergy","volume":"10","author":"Von Mutius","year":"2010","journal-title":"Nat Rev Immunol"},{"key":"ref6","doi-asserted-by":"publisher","first-page":"549","DOI":"10.1136\/thoraxjnl-2015-207295","article-title":"Bioaerosol production by patients with tuberculosis during normal tidal breathing: implications for transmission risk","volume":"71","author":"Wurie","year":"2016","journal-title":"Thorax"},{"key":"ref7","doi-asserted-by":"publisher","first-page":"23","DOI":"10.1016\/j.jes.2017.08.027","article-title":"Airborne bioaerosols and their impact on human health","volume":"67","author":"Kim","year":"2018","journal-title":"J Environ Sci"},{"key":"ref8","doi-asserted-by":"publisher","first-page":"1723","DOI":"10.1007\/s11869-021-00978-z","article-title":"Biological contaminants in the indoor air environment and their impacts on human health","volume":"14","author":"Kumar","year":"2021","journal-title":"Air Qual Atmos Health"},{"key":"ref9","doi-asserted-by":"publisher","first-page":"e0264226","DOI":"10.1371\/journal.pone.0264226","article-title":"Comprehensive health risk assessment of microbial indoor air quality in microenvironments","volume":"17","author":"Kumar","year":"2022","journal-title":"PLoS One"},{"key":"ref10","doi-asserted-by":"crossref","first-page":"15","DOI":"10.1007\/s10453-018-9534-6","article-title":"Aerial fungal spectrum of Kolkata, India, along with their allergenic impact on public health: a quantitative and qualitative evaluation","volume":"35","author":"Dey","year":"2019","journal-title":"Aerobiologia"},{"key":"ref11","doi-asserted-by":"publisher","first-page":"693","DOI":"10.1007\/s11869-019-00689-6","article-title":"Evaluating the colonization and distribution of fungal and bacterial bio-aerosol in Rajkot, western India using a multi-proxy approach","volume":"12","author":"Humbal","year":"2019","journal-title":"Air Qual Atmos Health"},{"key":"ref12","doi-asserted-by":"publisher","first-page":"148","DOI":"10.1093\/ijlct\/cty007","article-title":"Indoor air quality investigation of a university library based on field measurement and questionnaire survey","volume":"13","author":"Wu","year":"2018","journal-title":"Int J Low-Carbon Technol"},{"key":"ref13","doi-asserted-by":"crossref","first-page":"357","DOI":"10.1002\/9781394178964.ch17","article-title":"Guidelines for the biological contaminants in indoor areas","volume-title":"Airborne biocontaminants and their impact on human health","author":"Kumar","year":"2024"},{"key":"ref14","volume-title":"Indoor air quality: Biological contaminants. 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