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At least 19 recordsLinked to original sources
PubMed2026

Indoor Air Quality (IAQ) analysis and 16S rRNA gene sequencing of indoor air pollutants in a 3000-capacity religious auditorium.

A thorough molecular and environmental evaluation of microbial isolates and indoor air quality (IAQ) at a place of worship is presented in this work. The study used a dual-methodological approach, including systematic environmental monitoring to assess occupant health concerns and 16S rRNA gene sequencing for taxonomic identification. Four different bacterial isolates were successfully identified by molecular analysis using BLAST and phylogenetic reconstruction: Bacillus tropicus (A11), Leclercia adecarboxylata (A12), Acinetobacter sp. (A13), and Escherichia coli (A14). The evolutionary position of isolate A13 indicated possible horizontal gene transfer, underscoring the existence of flexible, opportunistic pathogens within the indoor environment, whereas isolates A11 and A14 demonstrated significant genetic stability. Concurrently, six sessions of air quality monitoring showed a thermally demanding environment, with humidity (56.00-70.51%) and temperatures (29.21-33.79 °C) continuously surpassing ASHRAE guidelines. The average pollutant concentrations are within WHO and USEPA safety criteria, however, there were outliers that may suggest sporadic pollutant penetration (outdoor) or resuspension of dust. The results demonstrate a clear relationship between increased chemical pollutants (TVOCs) and reduced thermal comfort. To reduce the congregation's acute respiratory and cardiovascular risks, optimal ventilation systems and source-control measures are urgently needed, as evidenced by the presence of clinically relevant microorganisms combined with dangerous pollution levels.

Analysis↗
PubMed2026

Public Health Indoor Air Surveillance for Respiratory Pathogens: From Pilot to Citywide Implementation.

CONTEXT: Environmental surveillance has become an essential component of public health pathogen surveillance programs. Indoor air surveillance is a promising environmental surveillance method but has yet to be scaled citywide and incorporated into state and local public health programs. PROGRAM: The Chicago Department of Public Health established a citywide indoor air surveillance program to enhance monitoring of airborne pathogens and address gaps in existing surveillance. IMPLEMENTATION: The program began with a pilot phase from February to April 2023 at 5 sites, which informed expansion to 17 sites and 20 samplers across emergency departments (5), congregate (3), and community settings (15), across the city. Site staff conducted weekly cartridge exchanges for seven-day sample collection periods using AerosolSense and AirPrep Cub samplers, which were then processed at the Regional Innovative Public Health Laboratory for SARS-CoV-2, influenza, and respiratory syncytial virus. Samples were tested using quantitative polymerase chain reaction, and SARS-CoV-2-positive samples underwent whole genome sequencing to characterize circulating viral lineages. EVALUATION: From February 2023 to August 2025, 1246 samples were processed, with a mean compliance of 85% (SD = 0.149) for weekly cartridge exchanges and minimal operational disruption. The program data supported its use as a surveillance tool for respiratory pathogen detection and SARS-CoV-2 lineage monitoring, with 74% samples positive for at least 1 virus and 68% detecting SARS-CoV-2. DISCUSSION: The program successfully scaled to citywide coverage and was shown to be feasible and acceptable across sites. These results highlight the value of indoor air monitoring as a complementary surveillance tool and offer a framework for other jurisdictions seeking to enhance respiratory pathogen detection through establishing a citywide indoor air surveillance program. Facility-level sampling is aggregated across sites to capture citywide trends complementing clinical and wastewater surveillance, and provides insights into facility-level pathogen burden, not captured by other surveillance methods.

Humans↗
PubMed2025

Modeling airborne transmission of viral genome using computational fluid dynamics simulation: A case study for SARS-CoV-2 virus.

Predicting indoor air quality during infectious disease conditions relies on models simulating particle materials (PM)/bioaerosols distribution. Understanding the thermo-fluid properties of exhaled air is crucial for comprehending disease transmission dynamics. This study employs a computational fluid dynamics (CFD) model to simulate cough-induced particle dispersion in a closed space. Furthermore, the number of released particles and the presence of SARS-CoV-2 viral genomes by a cough were assessed (in eight COVID-19 patients). According to the CFD model, in the first 30 s of cough, the vertical height and lateral breadth of the particles' dispersion were up to 138cm and 92cm, respectively. As the distance from the patient's respiratory zone increased, the lateral distribution width of particles expanded, reaching 1.3 m at 2.4 m away. Larger droplets (> 62.5µ) were deposited at shorter distances, while smaller particles remained airborne longer. The comparison of experimental and simulated results focused on particle dispersion at specific distances from the patient, particularly in the 2.5µ range. The distribution pattern of PM2.5 and PM10 at a distance of 1 and 2 m for women, not men, is similar to the distribution pattern of PM in CFD modeling. Viral genome detection was more prevalent in particles near the left side of the body, especially within the first 20 min post-cough, exhibiting a correlation with CFD predictions.

Airborne transmission↗
PubMed2026

Exploring China's Clean Air Act and associated cardiovascular disease risk: a prospective, quasi-experimental, and causal inference modelling study.

BACKGROUND: Substantial improvements in air quality have been recorded following the implementation of China's Clean Air Act (CCAA) in 2013. However, the association between CCAA implementation and individual-level cardiovascular disease (CVD) risk remains unclear. We aimed to examine the long-term association between CCAA implementation and individual-level predicted CVD risk. METHODS: In this prospective, quasi-experimental study, we used data from the China Kadoorie Biobank, a prospective cohort study that recruited participants from five urban and five rural areas across China between 2004 and 2008, with three resurveys conducted after the baseline survey (in 2008, 2013-14, and 2020-21). We included 34 862 individuals (mean age 51·3 years) who participated in at least one resurvey and had no history of CVD at baseline. Participants were classified into intervention (n=25 497) and control (n=9365) groups based on the local government's targets for particulate matter reduction. We estimated the 10-year risk of incident CVD morbidity or mortality using a validated risk prediction model. We used a difference-in-difference model to assess the long-term association between CCAA implementation and predicted risk, with adjustments made for regional confounders and individual-level characteristics, including demographics, lifestyle factors, medical history, and indoor air pollution exposure. The relationship between changes in long-term exposure to PM2·5, PM10, and O3 and predicted risk after CCAA implementation was analysed using a linear model. The estimated risk differences associated with air pollutant changes were estimated based on the magnitude of changes and their corresponding effect sizes. FINDINGS: After the CCAA was implemented, PM2·5 and PM10 concentrations declined in both groups, but O3 concentrations increased. The intervention group showed a 3·95% (95% CI 3·18-4·72%) lower increase in predicted risk than the control group, with larger estimated differences under stricter enforcement. Between 2013 and 2021, each 10 μg/m3 change in PM2·5 concentration was positively associated with a 1·80 (1·34-2·27) percentage point change in predicted CVD risk, whereas each 10 μg/m3 change in PM10 concentration was associated with a 1·24 (0·84-1·63) percentage point change and each 10 μg/m3 change in O3 concentration with a 0·58 (0·33-0·83) percentage point change. Overall, the observed changes in air pollutants during the study period were associated with an average 6·6 percentage point reduction in predicted CVD risk. INTERPRETATION: The CCAA and improved air quality were associated with a slower increase in predicted CVD risk, supporting the necessity for stricter, multipollutant air quality policies to maximise public health benefits. FUNDING: National Natural Science Foundation of China, Kadoorie Charitable Foundation, Noncommunicable Chronic Diseases-National Science and Technology Major Project, National Key R&D Program of China, Chinese Ministry of Science and Technology, and UK Wellcome Trust.

Journal Article↗
PubMed1979

Aerometric study of viable fungus spores in an animal care facility.

Studies of airborn fungi were undertaken to evaluate exposure risks for laboratory animals and human handlers which might lead to allergic or invasive disease. Although sporadically high fungus levels were encountered, counts of viable fungus particles were in general low. Recoveries on malt extract agar significantly exceeded those on Sabouraud dextrose agar. The taxa most frequently and abundantly recovered were Penicillium species. Data analyses suggest that 'clean' bedding material may be the principal source of these spores, that cleaning temporarily increases spore levels, and that outdoor airborne fungi contributed little to the indoor air spora identified. Aspergillus fumigatus was infrequently encounted in our samples, and dermatophytes were not recovered.

Air Microbiology↗
PubMed1979

[Passive smoking].

Passive smoking is the involuntary inspiration of smoky indoor air. Based on the information available today, it may be assumed that passive smoking normally is no health hazard as far as the classical smoker's diseases (lung cancer, myocardial infarct, etc.) are concerned. Nevertheless, it is probable that irritations caused by tobacco smoke have an unfavorable influence on the health of small children and that of already sick persons. The main problem of passive smoking is annoyance due to odor and irritations of eyes and respiratory organs. Our investigations in a climatic chamber with healthy subjects show that air pollution caused by tobacco smoke as indicated by 5 ppm CO leads to marked eye irritations--objectively as well as subjectively--in 15 to 20% of the subjects. This corresponds to smoking 10 cigarettes per hour in a small room with an air ventilation rate of four times per hour. If air pollution caused by tobacco smoke lies below the level of 2 ppm CO, irritations and annoyance for healthy persons are regarded as low and tolerable. This corresponds to about four cigarettes per hour under the same circumstances.

Adult↗
PubMed1978

[Occurrence of Aspergillus fumigatus in West Berlin - contribution to the epidemiology of aspergillosis (author's transl)].

The increasing incidence of human A. fumigatus infections particularly such of the respiratory tract has led to this study of the epidemiological situation. During the period between October 1968 and December 1977, A. fumigatus was isolated from clinical material in 425 cases. These findings which were established at the Mycology Unit, Robert Koch Institute, Federal Health Office, exhibited the following distribution by regions of the body or type of specimen: respiratory tract 277 (65.1(); venous blood 58 (13.6%); urine 3 (0.7%); stools 9 (2.1%) and others 78 (18.3%). Approximately two thirds of these findings were made during the period from October to March and about one third between April and September. The presence of A. fumigatus in the air both indoors and outdoors and also in the environment of patients suffering from aspergillosis was studied with the aid of the sedimentation-method. This method was chosen because the occurrence of A. fumigatus conidia in the air is of epidemiological interest. The number of isolations of A. fumigatus from outdoors samples was low, so the search for inhalative conidia concentrated upon sites near A. fumigatus habitats. These studies revealed that aspergillosis patients, clinical material sampled from them, decaying plant material (agriculture, horticulture), and used clothes and linen may form foci for the spread of A. fumigatus conidia. The control of aspergillosis in the hospital environment involves in particular a control of aspergillosis patients by means of culture and serology (preferably by ghe immunodiffusion test). Numerous recommendations are made on how to prevent A. fumigatus infections in hospitals, at the working site, and in the laboratory.

Air Microbiology↗
PubMedDate not supplied

Indoor spread of respiratory infection by recirculation of air.

Stimulated by an outbreak of measles that was spread throughout a school by the ventilating system, we looked into the possibility of preventing this hazard in air conditioned buildings. The amount of air recirculated by air conditioning systems increases as the temperature difference between indoor and outdoor air increases and often exceeds 70 per cent. Germicidal u.v. radiation in central supply ducts seems almost ideally suited for disinfecting recirculated air, being effective, safe, and cheap. The effectiveness of disinfecting recirculated air in blocking person to person transmission of airborne infection can be predicted to be great at the beginning of a potential outbreak and negligible during an established epidemic. Infection introduced by the air conditioning process, recently implicated in causing Legionnaires' Disease, might also be prevented. Air disinfection would supplement immunization in the control of respiratory infection and might be cost effective.

Air Conditioning↗
PubMed2026

Diversity analysis of indoor and outdoor fungal bioaerosols in UK households: a prospective, observational, longitudinal study.

BACKGROUND: Long-term exposure to indoor fungal bioaerosols is a recognised risk factor for respiratory illness, particularly in damp and poorly ventilated housing. However, the diversity and seasonal variability of these fungal communities are poorly understood. As part of the West London Healthy Home and Environment Study (WellHome), this study aimed to characterise the composition, diversity, and temporal dynamics of indoor fungal bioaerosols in urban UK homes, as compared with outdoor air, to inform future exposure baselines and policy development. METHODS: In this prospective, community-based observational study, 118 households were recruited across West London, UK, via community networks and partner organisations, prioritising families with children aged 5-17 years with asthma or allergies, from diverse socioeconomic backgrounds. Sampling occurred between Oct 3, 2022, and June 14, 2024. Participant data were collected via questionnaires completed by household members, capturing demographics, building characteristics, and respiratory health. Passive-air samplers were used in living rooms for 28 days during two seasonal campaigns, with concurrent outdoor sampling at four fixed community sites. Fungal bioaerosols were identified by ITS2 amplicon sequencing and quantified using broad-range quantitative PCR targeting the 18S rRNA gene. Diversity indexes and temporal dynamics were analysed using ecological statistics and generalised additive models. FINDINGS: 118 households were enrolled, comprising 504 residents (263 women, 237 men, and four not reported). Among 504 participants who self-identified, the largest groups comprised individuals identifying as Black African (n=47), Somali (n=46), White British (n=42), and African (n=38), with additional representation from mixed race ethnic backgrounds (n=29), Black British (n=27), White (n=22), and Black Caribbean (n=18), alongside several other ethnicities each represented at lower frequencies. Of 118 households, 104 completed both seasonal campaigns and 14 completed one, yielding 262 air samples (222 indoor and 40 outdoor). DNA was successfully recovered from all samples, identifying 2027 fungal genera. Indoor environments showed significantly higher richness (mean 646 vs 495 amplicon sequence variants; p<0&#xb7;0001) and Shannon diversity (4&#xb7;21 vs 3&#xb7;53; p<0&#xb7;0001) than outdoors. Community composition differed markedly (permutational multivariate ANOVA p<0&#xb7;0001), with Penicillium, Aspergillus, and Wallemia enriched indoors. Indoor fungal communities presented stronger seasonal cycling (R2=0&#xb7;203) than outdoor communities (R2=0&#xb7;012). Fungal burden across all homes had a median 11&#x2009;043 genomic equivalence (GE); IQR 4598-20&#x2009;579 GE. The highest levels were observed in homes with visible mould; one household showed elevated Aspergillus exposure linked to repeated asthma hospitalisations in a sensitised resident. INTERPRETATION: Indoor fungal bioaerosols are more diverse and dynamic than outdoor communities in urban UK homes. These findings establish foundational exposure data and highlight the need for incorporating fungal bioaerosol monitoring into public health policy to mitigate mould-related health risks. FUNDING: UK Research and Innovation (UKRI) Strategic Priorities Fund (SPF) Clean Air Programme.

Humans↗
PubMed2026

Unveiling microbial risks in Chinese household dust: a comprehensive analysis from absolute abundance to virulence unit.

BACKGROUND: People spend the majority of their lives indoors, yet the risk and virulence potential of household microbiota remain largely unexplored, particularly in developing countries. RESULTS: Here, we conducted a nationwide survey on both dust samples and health information across 118 Chinese households. The microbiota composition and its functional units were analyzed using absolute 16S rRNA/ITS sequencing, metagenomics, and metaproteomics. Cross-domain network analysis of the core microbial communities revealed robust co-occurrence patterns in household dust. The mean absolute abundance of potentially pathogenic bacteria and fungi in households was 2.39&#x2009;&#xd7;&#x2009;105 and 2.83&#x2009;&#xd7;&#x2009;106 DNA copies/g dust. The potentially pathogenic community was primarily influenced by latitude, relative humidity, and average temperature. Although total absolute abundance was substantially lower in urban areas, the relative abundance of potentially pathogenic bacteria was markedly higher compared to rural environments. While urban-rural differences existed, the underlying statistical drivers were the environmental variables. The absolute abundance of potential pathogens was significantly associated with the prevalence of rhinitis, wheeze, and dermatitis in 266 participants. Children were identified as the highest-risk group from inhalation exposure of average daily dose. A total of 170 bacterial, 223 fungal virulence factors (VFs), and 370 antibiotic resistance genes (ARGs) were detected in dust and dust extracellular vesicle (EV)-associated DNA. EV-associated cargoes contributed 47.13% to the bacterial VF profiles, 11.90% to fungal VF&#xa0;profiles, and 44.45% to ARG profiles. Metaproteomic analysis confirmed the presence of VF profiles in dust EVs, which was further verified by curated proteomics data from 35 household pathogens. CONCLUSIONS: This study provides a comprehensive, quantitative framework linking indoor microbial exposure to health risks, highlighting EVs as a non-negligible, novel, extracellular mechanistic pathway for health impact in household environments. Video Abstract.

Child↗
PubMed2026

Comparison of black carbon measurements using filter-specific reference transmittance to those using lab blanks or an average of unloaded filters.

Filter-based optical techniques compare light transmission intensities between loaded (I) and unloaded (I0) filters as a measure of light-absorbing mass for subsequent estimations of equivalent black carbon (eBC). We analyzed 5,379 15&#x2009;mm Teflon filters from the Household Air Pollution Intervention Network (HAPIN) trial to assess the influence that different methods of I0 estimations have on eBC measures. We compared eBC measurements using filter-specific I0 values (Method 1) to those using three other methods of I0 estimation: the lab blank scan from a given session (Method 2), the average of all pre-sample filter scans (Method 3), and the average of all lab blank filter scans (Method 4). We assessed the agreement between Method 1 and the alternative methods using Bland-Altman analysis. We also assessed the relationship between Method 1 and the alternative methods across the complete measurement range and after stratifying exposure data into quartiles according to Method 1 eBC exposures. The mean (SD) personal eBC exposure for Method 1 was 7.8&#x2009;&#x3bc;g/m3 (5.9), and exposures ranged from 1.3 to 46.8&#x2009;&#x3bc;g/m3. Compared to Method 1, eBC using Methods 2, 3, and 4 were higher by 0.7&#x2009;&#x3bc;g/m3, 0.1&#x2009;&#x3bc;g/m3, and 0.7&#x2009;&#x3bc;g/m3, respectively. The performances of linear regression models between Method 1 and all other methods were moderate to strong (R2 range: 0.42-0.93) in the second, third, and fourth quartiles; however, the models in the first quartile (eBC range: 1.3-2.9&#x2009;&#x3bc;g/m3) performed poorly (R2&#x2009;=&#x2009;0.25-0.26), with error approximately 25% of the mean. Our findings suggest that, in most instances, conventional methods for obtaining I0 values can be used to sufficiently characterize eBC; however, analyzing filters before sampling adds appreciably to the accuracy of eBC estimations in lower concentration settings.Implications: Filter-based optical techniques compare light transmission intensities between loaded (I) and unloaded (I0) filters as a measure of light-absorbing mass for subsequent estimations of equivalent black carbon (eBC). To assess the influence that different methods of I0 estimations have on eBC measures, we analyzed 5,379 15 mm Teflon filters from the Household Air Pollution Intervention Network (HAPIN) trial. Our findings suggest that, in most instances, conventional methods for obtaining I0 values can be used to sufficiently characterize eBC; however, analyzing filters before sampling adds appreciably to the accuracy of eBC estimations in lower concentration settings.

Soot↗
PubMed2026

Prenatal exposure to indoor PM2.5 and children's cognitive performance at 4 years of age: an observational analysis from the UGAAR randomized controlled trial.

Outdoor fine particulate matter (PM2.5) concentrations during pregnancy are linked to reduced cognitive performance in children. We previously reported that portable HEPA filter air cleaners use during pregnancy improved children's mean full-scale IQ (FSIQ), but no previous studies have evaluated the relationship between indoor PM2.5 during pregnancy and FSIQ in childhood. We conducted an observational analysis using data from the Ulaanbaatar Gestation and Air Pollution Research (UGAAR) randomized controlled trial. Using a previously developed model of weekly indoor PM2.5 concentrations, we estimated the average concentrations in participants' homes over the full pregnancy and in each trimester. When the children were four years old, we measured FSIQ using the Wechsler Preschool and Primary Scale of Intelligence (WPPSI-IV). We used multiple linear regression to assess the adjusted relationships between interquartile range (IQR) contrasts in indoor PM2.5 during pregnancy and FSIQ among 475 mother-child dyads. An 8.8&#xa0;&#x3bc;g/m3 increase in indoor PM2.5 concentration over the full pregnancy was associated with a reduction of 1.4 points (95% CI: -3.4, 0.6) in mean FSIQ. The strongest association between PM2.5 concentrations and FSIQ was in the first trimester, when a 19.1&#xa0;&#x3bc;g/m3 contrast was associated with a 2.8-point reduction (95% CI: -5.7, 0.2) in mean FSIQ. Indoor PM2.5, particularly during early pregnancy, may impair brain development, leading to lower mean FSIQ scores in four-year old children. These results, combined with our previous analysis of HEPA filter air cleaners, indicate that reducing PM2.5 exposure during pregnancy has beneficial effects on children's cognitive performance.

Humans↗
PubMed2026

Air Pollution and Heat Impacts on Respiratory Morbidity and Mortality Outcomes in Africa: A Systematic Review Towards a Meta-analysis.

PURPOSE OF THE REVIEW: This review synthesised evidence on associations between air pollution and respiratory morbidity in Africa. Following PRISMA guidelines, we systematically searched PubMed, ScienceDirect and Elicit for case-control studies published between 2015 and 2025. RECENT FINDINGS: Thirteen studies from ten African countries reported pollutant levels far exceeding WHO guidelines. Indoor PM&#x2082;.&#x2085; in biomass-using homes ranged from 96 to 177&#xa0;&#xb5;g/m&#xb3;, and ambient PM&#x2082;.&#x2085; reached 259&#xa0;&#xb5;g/m&#xb3;. Nitrogen oxides were consistently associated with reduced lung function in children, while household air pollution increased risks of under-five mortality and low birthweight. Associations with acute respiratory infections varied across settings. Vulnerability was greatest among young children, those with airway hyperresponsiveness, and households with poor ventilation. Only three studies included temperature, and none examined heat-respiratory interactions. Across African case-control studies, particulate matter and household air pollution remain consistently linked to adverse respiratory outcomes, highlighting urgent needs for cleaner fuels, improved ventilation, and stronger evidence on combined pollution and heat exposures.

Humans↗
PubMed1979

Factors of importance in determining the prevalence of indoor molds.

The concentration of molds isolated in 68 homes of allergic patients in southern California using the Andersen volumetric sampler varied from a minimum of 36 to a maximum of 5,984 isolate/M3 air sampled. The most frequently isolated included Cladosporium, Penicillium species. Alternaria, Sterile (Non-sporulating) Mycelium, Epicoccum, Aspergillus species, Aureobasidium and Dreschlera. Statistically significant higher mold isolates were associated with high shade and high levels of organic debris near the home and poor landscaping and landscape maintenance. Low concentrations of mold isolates were associated with the presence of a central electrostatic filtration system and good compliance with dust controls. The viable mold spore levels were lower in homes where the electrostatic filtration unit was operated continuously rather than intermittently. No statistically significant correlations could be made between indoor mold isolates and any of the following: number and age of the occupants, age and size of home, month of survey or the presence of indoor plants.

Air Pollutants↗
PubMed1978

Airborne Aspergillus fumigatus levels outside and within a large clinical center.

Most considerations of Aspergillus fumigatus prevalence have implied that patterns of occurrence observed within London hospitals are generally applicable. Since prevalence data are almost nonexistent elsewhere, this assumption remains untested. To provide a comparison relevant to North America, we have monitored thermotolerant fungi outside as well as at two sites within the University Hospital, Ann Arbor, Michigan, during one year. Collections were made with paired Andersen samplers and malt agar for 30- to 40-min periods in a hallway adjacent to 6W, a general medical ward (47 days), and 2W, a lower level service and supply area (40 days); in addition, 10-min outdoor samples (44 days) were taken on an unobstructed hospital rooftop (out). Recoveries were analyzed after 3 and 7 days of 37 degrees C aerobic incubation. Virtually complete suppression of Cladosporium form species at 37 degrees left a mycoflora with A. fumigatus, A. niger, Paecilomyces spp., Mucor spp., and yeast/bacteria predominating. Although the proportions of samples yielding A. fumigatus were 76% for 6W, 57% for 2W, and 56% (out), levels exceeded 40 isolates/m3 only twice and were over 10 isolates/m3 on only 10 of 131 total samples. For 6W, 2W and out, respectively, means were 4.78, 1.97, and 6.25 isolates/m3; medians were 1.20, 1.05 and 1.75/m3 without annual trends indoors and with only a limited outdoor summer increase. Our data fail entirely to show the fall-winter abundance observed in the London report and suggest substantially lower indoor exposure levels of A. fumigatus than those noted in London.

Air Microbiology↗