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Exposure to viable bacterial and fungal spores re-aerosolized from air handling filters may create a major health risk. Assessing and controlling this exposure have been of interest to the bio-defense and indoor air quality communities. Methods are being developed for inactivating stress-resistant viable microorganisms collected on ventilation filters. Here we investigated the inactivation of spores of Bacillus thuringiensis var. kurstaki (Btk), a recognized simulant for B. antracis, and Aspergillus fumigatus, a common opportunistic pathogen used as an indicator for indoor air quality. The viability change was measured on filters treated with ultraviolet (UV) irradiation and gaseous iodine. The spores were collected on high-efficiency particulate air (HEPA) and non-HEPA filters, both flattened for testing purposes to represent "surface" filters. A mixed cellulose ester (MCE) membrane filter was also tested as a reference. Additionally, a commercial HEPA unit with a deep-bed (non-flattened) filter was tested. Combined treatments of Btk spores with UV and iodine on MCE filter produced a synergistic inactivation effect. No similar synergy was observed for A. fumigatus. For spores collected on an MCE filter, the inactivation effect was about an order of magnitude greater for Btk compared to A. fumigatus. The filter type was found to be an important factor affecting the inactivation of Btk spores while it was not as influential for A. fumigatus. Overall, the combined effect of UV irradiation and gaseous iodine on viable bacterial and fungal spores collected on flat filters was found to be potent. The benefit of either simultaneous or sequential treatment was much lower for Btk spores embedded inside the deep-bed (non-flattened) HEPA filter, but for A. fumigatus the inactivation on flattened and non-flattened HEPA filters was comparable. For both species, applying UV first and gaseous iodine second produced significantly higher inactivation than when applying them simultaneously or in an opposite sequence., (Copyright © 2019 Elsevier B.V. All rights reserved.)

People generally spend more time indoors than outdoors resulting in a higher proportion of exposure to particulate matter (PM) occurring indoors. Consequently, indoor PM levels, in contrast to outdoor PM levels, may have a stronger relationship with lung function. To test this hypothesis, indoor and outdoor PM 2.5 and fungal spore data were simultaneously collected from the homes of forty-four asthmatic children aged 10-16 years. An optical absorption technique was utilized on the collected PM 2.5 mass to obtain concentrations of black carbon (BC) and ultraviolet light absorbing particulate matter, (UVPM; a marker of light absorbing PM 2.5 emitted from smoldering organics). Enrolled children completed spirometry after environmental measurements were made. Given the high correlation between PM 2.5 , BC, and UVPM, principal component analysis was used to obtain uncorrelated summaries of the measured PM. Separate linear mixed-effect models were developed to estimate the association between principal components of the PM variables and spirometry values, as well as the uncorrelated original PM variables and spirometry values. A one-unit increase in the first principal component variable representing indoor PM (predominantly composed of UVPM and PM 2.5 ) was associated with 4.1% decrease (99% CI = -6.9, -1.4) in FEV 1 /FVC ratio. 11.3 μg/m 3 increase in indoor UVPM was associated with 6.4% and 14.7% decrease (99% CI = -10.4, -2.4 and 99% CI = -26.3, -2.9, respectively) in percent predicted FEV 1 /FVC ratio and FEF 25-75 respectively. Additionally, 17.7 μg/m 3 increase in indoor PM 2.5 was associated with 6.1% and 12.9% decrease (99% CI = -10.2, -1.9 and 99% CI = -24.9, -1.0, respectively) in percent predicted FEV 1 /FVC ratio and FEF 25-75 , respectively. Outdoor PM, indoor BC, and indoor fungal spores were not significantly associated with lung function. The results indicate that indoor PM is more strongly associated with lung function in children with asthma as compared with outdoor PM., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Green eco-friendly housing includes approaches to reduce indoor air pollutant sources and to increase energy efficiency. Although sealing/tightening buildings can save energy and reduce the penetration of outdoor pollutants, an adverse outcome can be increased buildup of pollutants with indoor sources. The objective of this study was to determine the differences in the indoor air quality (IAQ) between green and non-green homes in low-income housing complexes. In one housing complex, apartments were renovated using green principles (n=28). Home visits were conducted immediately after the renovation, and subsequently at 6 months and at 12 months following the renovation. Of these homes, eight homes had pre-renovation home visits; this allowed pre- and post-renovation comparisons within the same homes. Parallel visits were conducted in non-green (control) apartments (n=14) in a nearby low-income housing complex. The IAQ assessments included PM2.5, black carbon, ultrafine particles, sulfur, total volatile organic compounds (VOCs), formaldehyde, and air exchange rate. Data were analyzed using linear mixed-effects models. None of the indoor pollutant concentrations were significantly different between green and non-green homes. However, we found differences when comparing the concentrations before and after renovation. Measured immediately after renovation, indoor black carbon concentrations were significantly lower averaging 682 ng/m(3) in post-renovation vs. 2364 ng/m(3) in pre-renovation home visits (p=0.01). In contrast, formaldehyde concentrations were significantly higher in post-renovated (0.03 ppm) than in pre-renovated homes (0.01 ppm) (p=0.004). Questionnaire data showed that opening of windows occurred less frequently in homes immediately post-renovation compared to pre-renovation; this factor likely affected the levels of indoor black carbon (from outdoor sources) and formaldehyde (from indoor sources) more than the renovation status itself. To reduce IAQ problems and potentially improve health, careful selection of indoor building materials and ensuring sufficient ventilation are important for green building designs., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Destruction of bioweapon facilities due to explosion or fire could aerosolize highly pathogenic microorganisms. The post-event air quality assessment is conducted through air sampling. A bioaerosol sample (often collected on a filter for further culture-based analysis) also contains combustion products, which may influence the microbial culturability and, thus, impact the outcome. We have examined the interaction between spores deposited on collection filters using two simulants of Bacillus anthracis [B. thuringiensis (Bt) and B. atrophaeus (referred to as BG)] and incoming combustion products of Al as well as Mg and B·Ti (common ingredient of metalized explosives). Spores extracted from Teflon, polycarbonate, mixed cellulose ester (MCE), and gelatin filters (most common filter media for bioaerosol sampling), which were exposed to combustion products during a short-term sampling, were analyzed by cultivation. Surprisingly, we observed that aluminum combustion products enhanced the culturability of Bt (but not BG) spores on Teflon filters increasing the culturable count by more than an order of magnitude. Testing polycarbonate and MCE filter materials also revealed a moderate increase of culturability although gelatin did not. No effect was observed with either of the two species interacting on either filter media with products originated by combustion of Mg and B·Ti. Sample contamination, spore agglomeration, effect of a filter material on the spore survival, changes in the spore wall ultrastructure and germination, as well as other factors were explored to interpret the findings. The study raises a question about the reliability of certain filter materials for collecting airborne bio-threat agents in combustion environments., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Several low weight molecules have often been implicated in the induction of occupational asthma. Glyphosate, a small molecule herbicide, is widely used in the world. There is a controversy regarding a role of glyphosate in developing asthma and rhinitis among farmers, the mechanism of which is unexplored. The aim of this study was to explore the mechanisms of glyphosate induced pulmonary pathology by utilizing murine models and real environmental samples. C57BL/6, TLR4-/-, and IL-13-/- mice inhaled extracts of glyphosate-rich air samples collected on farms during spraying of herbicides or inhaled different doses of glyphosate and ovalbumin. The cellular response, humoral response, and lung function of exposed mice were evaluated. Exposure to glyphosate-rich air samples as well as glyphosate alone to the lungs increased: eosinophil and neutrophil counts, mast cell degranulation, and production of IL-33, TSLP, IL-13, and IL-5. In contrast, in vivo systemic IL-4 production was not increased. Co-administration of ovalbumin with glyphosate did not substantially change the inflammatory immune response. However, IL-13-deficiency resulted in diminished inflammatory response but did not have a significant effect on airway resistance upon methacholine challenge after 7 or 21 days of glyphosate exposure. Glyphosate-rich farm air samples as well as glyphosate alone were found to induce pulmonary IL-13-dependent inflammation and promote Th2 type cytokines, but not IL-4 for glyphosate alone. This study, for the first time, provides evidence for the mechanism of glyphosate-induced occupational lung disease., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

The study aimed at investigating Gram-positive and Gram-negative bacteria in moldy and non-moldy homes, as defined by the home's Environmental Relative Moldiness Index (ERMI) value. The ERMI values were determined from floor dust samples in 2010 and 2011 and homes were classified into low (<5) and high (>5) ERMI groups based on the average ERMI values as well as 2011 ERMI values. Dust and air samples were collected from the homes in 2011 and all samples were analyzed for Gram-positive and Gram-negative bacteria using QPCR assays, endotoxin by the LAL assay, and N-acetyl-muramic acid using HPLC. In addition, air samples were analyzed for culturable bacteria. When average ERMI values were considered, the concentration and load of Gram-positive bacteria determined with QPCR in house dust, but not air, were significantly greater in high ERMI homes than in low ERMI homes. Furthermore, the concentration of endotoxin, but not muramic acid, in the dust was significantly greater in high ERMI than in low ERMI homes. In contrast, when ERMI values of 2011 were considered, Gram-negative bacteria determined with QPCR in air, endotoxin in air, and muramic acid in dust were significantly greater in high ERMI homes. The results suggest that both short-term and long-term mold contamination in homes could be linked with the bacterial concentrations in house dust, however, only the current mold status was associated with bacterial concentrations in air. Although correlations were found between endotoxin and Gram-negative bacteria as well as between muramic acid and Gram-positive bacteria in the entire data set, diverging associations were observed between the different measures of bacteria and the home moldiness. It is likely that concentrations of cells obtained by QPCR and concentrations of cell wall components are not equivalent and represent too broad categories to understand the bacterial composition and sources of the home microbiota., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Previously, we demonstrated that infants residing in homes with higher Environmental Relative Moldiness Index were at greater risk for developing asthma by age seven. The purpose of this analysis was to identify the family and home characteristics associated with higher moldiness index values in infants' homes at age one. Univariate linear regression of each characteristic determined that family factors associated with moldiness index were race and income. Home characteristics associated with the moldiness index values were: air conditioning, carpet, age of the home, season of home assessment, and house dust mite allergen. Parental history of asthma, use of dehumidifier, visible mold, dog and cat allergen levels were not associated with moldiness index. Results of multiple linear regression showed that older homes had 2.9 units higher moldiness index (95% confidence interval [CI]=0.4, 5.4), whereas homes with central air conditioning had 2.5 units lower moldiness index (95% CI=-4.7, -0.4). In addition, higher dust mite allergen levels and carpeting were positively and negatively associated with higher moldiness index, respectively. Because older homes and lack of air conditioning were also correlated with race and lower income, whereas carpeting was associated with newer homes, the multivariate analyses suggests that lower overall socioeconomic position is associated with higher moldiness index values. This may lead to increased asthma risk in homes inhabited by susceptible, vulnerable population subgroups. Further, age of the home was a surrogate of income, race and carpeting in our population; thus the use of these factors should carefully be evaluated in future studies., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Exposure to traffic-related pollution during childhood has been associated with asthma exacerbation, and asthma incidence. The objective of the Cincinnati Childhood Allergy and Air Pollution Study (CCAAPS) is to determine if the development of allergic and respiratory disease is associated with exposure to diesel engine exhaust particles. A detailed receptor model analyses was undertaken by applying positive matrix factorization (PMF) and UNMIX receptor models to two PM₂.₅ data sets: one consisting of two carbon fractions and the other of eight temperature-resolved carbon fractions. Based on the source profiles resolved from the analyses, markers of traffic-related air pollution were estimated: the elemental carbon attributed to traffic (ECAT) and elemental carbon attributed to diesel vehicle emission (ECAD). Application of UNMIX to the two data sets generated four source factors: combustion related sulfate, traffic, metal processing and soil/crustal. The PMF application generated six source factors derived from analyzing two carbon fractions and seven factors from temperature-resolved eight carbon fractions. The source factors (with source contribution estimates by mass concentrations in parentheses) are: combustion sulfate (46.8%), vegetative burning (15.8%), secondary sulfate (12.9%), diesel vehicle emission (10.9%), metal processing (7.5%), gasoline vehicle emission (5.6%) and soil/crustal (0.7%). Diesel and gasoline vehicle emission sources were separated using eight temperature-resolved organic and elemental carbon fractions. Application of PMF to both datasets also differentiated the sulfate rich source from the vegetative burning source, which are combined in a single factor by UNMIX modeling. Calculated ECAT and ECAD values at different locations indicated that traffic source impacts depend on factors such as traffic volumes, meteorological parameters, and the mode of vehicle operation apart from the proximity of the sites to highways. The difference in ECAT and ECAD, however, was less than one standard deviation. Thus, a cost benefit consideration should be used when deciding on the benefits of an eight or two carbon approach., (Published by Elsevier B.V.)

This study examined: (i) biocontaminant levels in flooded homes of New Orleans two years after the flooding; (ii) seasonal changes in biocontaminant levels, and (iii) correlations between biocontaminant levels obtained by different environmental monitoring methods. Endotoxin, (1→3)-β-d-glucan, fungal spores, and dust mite allergens were measured in 35 homes during summer and winter. A combination of dust sampling, aerosolization-based microbial source assessment, and long-term inhalable bioaerosol sampling aided in understanding exposure matrices. On average, endotoxin found in the aerosolized fraction accounted for <2% of that measured in the floor dust, suggesting that vacuuming could overestimate inhalation exposures. In contrast, the (1→3)-β-d-glucan levels in the floor dust and aerosolized fractions were mostly comparable, and 25% of the homes showed aerosolizable levels even higher than the dust-borne levels. The seasonal patterns for endotoxin in dust and the aerosolizable fraction were different from those found for (1→3)-β-d-glucan, reflecting the temperature and humidity effects on bacterial and fungal contamination. While the concentration of airborne endotoxin followed the same seasonal trend as endotoxin aerosolized from surfaces, no significant seasonal difference was identified for the concentrations of airborne (1→3)-β-d-glucan and fungal spores. This was attributed to the difference in the particle size; smaller endotoxin-containing particles can remain airborne for longer time than larger fungal spores or (1→3)-β-d-glucan-containing particles. It is also possible that fungal aerosolization in home environments did not reach its full potential. Detectable dust mite allergens were found only in dust samples, and more commonly in occupied homes. Levels of endotoxin, (1→3)-β-d-glucan, and fungi in air had decreased during the two-year period following the flooding as compared to immediate measurements; however, the dust-borne endotoxin and (1→3)-β-d-glucan levels remained elevated. No conclusive correlations were found between the three environmental monitoring methods. The findings support the use of multiple methods when assessing exposure to microbial contaminants., (Copyright © 2010 Elsevier B.V. All rights reserved.)

The main study objective was to compare different methods for assessing mold exposure in conjunction with an epidemiologic study on the development of children's asthma. Homes of 184 children were assessed for mold by visual observations and dust sampling at child's age 1 (Year 1). Similar assessment supplemented with air sampling was conducted in Year 7. Samples were analyzed for endotoxin, (1-3)-β-D-glucan, and fungal spores. The Mold Specific Quantitative Polymerase Chain Reaction assay was used to analyze 36 mold species in dust samples, and the Environmental Relative Moldiness Index (ERMI) was calculated. Homes were categorized based on three criteria: 1) visible mold damage, 2) moldy odor, and 3) ERMI. Even for homes where families had not moved, Year 7 endotoxin and (1-3)-β-d-glucan exposures were significantly higher than those in Year 1 (p<0.001), whereas no difference was seen for ERMI (p=0.78). Microbial concentrations were not consistently associated with visible mold damage categories, but were consistently higher in homes with moldy odor and in homes that had high ERMI. Low correlations between results in air and dust samples indicate different types or durations of potential microbial exposures from dust vs. air. Future analysis will indicate which, if any, of the assessment methods is associated with the development of asthma., (Copyright © 2010 Elsevier B.V. All rights reserved.)

Standing water and sediments remaining on flood-affected materials were the breeding ground for many microorganisms in flooded homes following Hurricane Katrina. The purpose of this laboratory study was to examine the aerosolization of culturable and total fungi, (1-->3)-beta-D glucan, and endotoxin from eight flood-affected floor and bedding materials collected in New Orleans homes, following Hurricane Katrina. Aerosolization was examined using the Fungal Spore Source Strength Tester (FSSST) connected to a BioSampler. Dust samples were collected by vacuuming. A two-stage cyclone sampler was used for size-selective analysis of aerosolized glucan and endotoxin. On average, levels of culturable fungi ranged from undetectable (lower limit=8.3 x 10(4)) to 2.6 x 10(5) CFU/m(2); total fungi ranged from 2.07 x 10(5) to 1.6 x 10(6) spores/m(2); (1-->3)-beta-D glucan and endotoxin were 2.0 x 10(3) - 2.9 x 10(4) ng/m(2) and 7.0 x 10(2) - 9.3 x 10(4) EU/m(2), respectively. The results showed that 5-15 min sampling is sufficient for detecting aerosolizable biocontaminants with the FSSST. Smaller particle size fractions (<1.0 and <1.8 microm) have levels of glucan and endotoxin comparable to larger (>1.8 microm) fractions, which raises additional exposure concerns. Vacuuming was found to overestimate inhalation exposure risks by a factor of approximately 10(2) for (1-->3)-beta-D glucan and by 10(3)-10(4) for endotoxin as detected by the FSSST. The information generated from this study is important with respect to restoration and rejuvenation of the flood-affected areas in New Orleans. We believe the findings will be significant during similar disasters in other regions of the world including major coastal floods from tsunamis.

Release of submicrometer-sized fungal fragments (<1.0 microm) was discovered in earlier studies, which investigated the aerosolization of spores from moldy surfaces. However, the contribution of fungal fragments to total mold exposure is poorly characterized. The purpose of this study was to investigate the size-fractionated concentrations of particulate (1-->3)-beta-D-glucan and numbers of particles aerosolized from the surface of artificially mold-contaminated materials using a novel sampling methodology. Aspergillus versicolor and Stachybotrys chartarum were grown on malt extract agar and building materials (ceiling tiles and gypsum board) for one to six months. Fungal particles released from these materials were collected size-selectively by a newly developed Fragment Sampling System, and (1-->3)-beta-D-glucan in air samples was analyzed by Limulus Amebocyte lysate (LAL) assay. The concentrations of (1-->3)-beta-D-glucan varied from 0.4x10(0) to 9.8x10(2) ng m(-3) in the fragment size and from 1.0x10(1) to 4.7x10(4) ng m(-3) in the spore size range. Numbers of submicrometer-sized particles aerosolized from 6-month old cultures were always significantly higher that those from 1-month old (P<0.001). This can be attributed to increased dryness on the surface of material samples and an increase in fungal biomass over time. The average fragment to spore ratios both in particle numbers and (1-->3)-beta-D-glucan mass were higher for S. chartarum than for A. versicolor. The results indicate that long-term mold damage in buildings may lead to increased contribution of fragments to the total mold exposure. Therefore, the health impact of these particles may be even greater than that of spores, considering the strong association between numbers of fine particles and adverse health effects reported in other studies. Furthermore, the contribution of fragments may vary between species and appears to be higher for S. chartarum than for A. versicolor.

Mold specific quantitative PCR (MSQPCR) was used to measure the concentrations of the 36 mold species in indoor and outdoor air samples that were taken simultaneously for 48 h in and around 17 homes in Cincinnati, Ohio. The total spore concentrations of 353 per m(3) of indoor air and 827 per m(3) of outdoor air samples were significantly different (por=0.5). These results suggest that interpretation of the meaning of short-term (<48 h) mold measurements in indoor and outdoor air samples must be made with caution.

The airborne fungal spore concentration measured with air samplers during specific time intervals does not always adequately represent the maximum spore concentration levels, because of the sporadic nature of spore release. Hence, a reliable method is needed to directly assess the indoor fungal sources with respect to their spore aerosolization potential. In this study, the newly developed fungal spore source strength tester (FSSST), which aerosolizes spores from growth surfaces and samples the airborne fungi into a bioaerosol sampler, was evaluated in the laboratory. The FSSST's operational flow rates of 30 and 12.5 l/min were tested. The fungal spores released from moldy surfaces were measured with an optical particle counter. Simultaneously, the spores were collected by a bioaerosol sampler: either with a 37-mm filter cassette or with the BioSampler. Three material types, ceiling tile, gypsum board and plastic sheet coated with agar, were tested after they were inoculated with the fungus Aspergillus versicolor. In addition, gypsum board naturally contaminated with various fungi (obtained from a mold-problem home) was tested in the laboratory using the FSSST. In all three laboratory-inoculated materials, the release rate of A. versicolor was found to be higher when the FSSST operated at 30 l/min than at 12.5 l/min. Nevertheless, even at 12.5 l/min the number of spores aerosolized from the source during 10 min was found sufficient to reflect the highest level of release that may occur in indoor environments. At 12.5 l/min, the release rate of A. versicolor during the first 10-min period was (23.9 +/- 17.7)x10(4) cm(-2) for ceiling tile, (1.3 +/- 0.3)x10(4) cm(-2) for gypsum board and (0.13 +/- 0.08)x10(4) cm(-2) for agar surface (based on the samples collected with the BioSampler). The spore release rate was higher during the first 10 min than during the second 10 min of the FSSST application. It was observed that the particles aerosolized from the A. versicolor culture included spore aggregates and single spores, as well as mycelial fragments. Overall, 0.6 +/- 0.3% of spores detected on 1 cm2 of ceiling tile inoculated with A. versicolor were aerosolized during the 10-min source testing. The respective number was 9.2 +/- 1.0% for the laboratory-inoculated gypsum board, 0.002 +/- 0.001% for the laboratory-inoculated plastic covered with agar and 1.8 +/- 0.2% for naturally contaminated gypsum board. Our data suggest that the FSSST provides very favorable conditions for the spore aerosolization and thus can be used in the field to assess the maximum potential spore release from a fungal source.

Molds are ubiquitous in every environment and many species have been recently associated with an increase in opportunistic infections in immunocompromised patients or the exacerbation of asthmatic episodes in allergic patients. The degree of environmental contamination with fungi thus needs to be monitored and in this study we report the development of a monoclonal antibody (mAb)-mediated enzyme-linked immunosorbent assay (ELISA) for the detection of spores of Penicillium brevicompactum in experimental model aerosols. In addition, we have investigated the influence of different parameters of air sampling and sample recovery on ELISA performance. MAbs were produced with standard hybridoma techniques and cross-reactivities were determined against spores of 53 fungal species by indirect ELISA. Standardized experimental fungal aerosols were collected with the Button Personal Inhalable Aerosol Sampler onto polycarbonate or polytetrafluoroethylene filters (PTFE) and the effects of different extraction buffers and filter agitation methods during sample processing on spore recovery and ELISA detection were investigated. Five mAbs were produced and all of them cross-reacted with several of 31 related Aspergillus, Penicillium and Eurotium species. However, cross-reactivities with 21 non-related fungi were rare. Spores were recovered in much higher numbers from polycarbonate filters (PFs) than from polytetrafluoroethylene filters. Optical densities (ODs) in ELISA were higher for spores collected into carbonate coating buffer (CCB) than phosphate-buffered saline (PBS). Filter bath sonication following filter vortexing had no positive effects on ELISA sensitivity. The cross-reactivity patterns of mAbs suggest that Aspergillus and Penicillium species share multiple antigens. Quantitative ELISA results for fungal aerosols were found to be influenced by differential sample processing and thus method standardization will be essential to maintain the comparability of immunometric monitoring results.

The release of Streptomyces albus propagules from contaminated agar and ceiling tile surfaces was studied under controlled environmental conditions in a newly developed aerosolization chamber. The experiments revealed that both spores and cell fragments can be simultaneously released from the colonized surface by relatively gentle air currents of 0.3 ms(-1). A 100 x increase of the air velocity can result in a 50-fold increase in the number of released propagules. The aerosolization rate depends strongly on the type and roughness of the contaminated surface. Up to 90% of available actinomycete propagules can become airborne during the first 10 min of the release process. Application of vibration to the surface did not reveal any influence on the aerosolization process of S. albus propagules under the tested conditions. This study has shown that propagules in the fine particle size range can be released in large amounts from contaminated surfaces. Measurement of the number of S. albus fragments in the vicinity of a contaminated area, as an alternative to conventional air or surface sampling, appears to be a promising approach for quantitative exposure assessment.