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Outdoor traffic-related airborne particles can infiltrate a building and adversely affect the indoor air quality. Limited information is available on the effectiveness of high-efficiency particulate air (HEPA) filtration of traffic-related particles. Here we investigated the effectiveness of portable HEPA air cleaners in reducing indoor concentrations of traffic-related and other aerosols, including black carbon (BC), PM(2.5), ultraviolet absorbing particulate matter (UVPM) (a marker of tobacco smoke), and fungal spores. This intervention study consisted of a placebo-controlled cross-over design, in which a HEPA cleaner and a placebo “dummy” were placed in homes for 4-weeks each, with 48-hour air sampling conducted prior to and during the end of each treatment period. The concentrations measured for BC, PM(2.5), UVPM, and fungal spores were significantly reduced following HEPA filtration, but not following the dummy period. The indoor fraction of BC/PM(2.5) was significantly reduced due to the HEPA cleaner, indicating that black carbon was particularly impacted by HEPA filtration. This study demonstrates that HEPA air purification can result in a significant reduction of traffic-related and other aerosols in diverse residential settings.

This study was to investigate the levels of heavy metals in PM2.5 and in blood, the prevalence of respiratory symptoms and asthma, and the related factors to them. Lead and cadmium in both PM2.5 and blood were significant higher in Guiyu (exposed area) than Haojiang (reference area) (p 5 mu g/dL was significantly associated with asthma (OR, 9.50; 95% CI, 1.16-77.49). Higher blood chromium and blood manganese were associated with more cough and wheeze, respectively. Our data suggest that living in e-waste exposed area may lead to increased levels of heavy metals, and accelerated prevalence of respiratory symptoms and asthma. (C) 2016 Elsevier Ltd. All rights reserved.

The objective of this study was to investigate the protection level offered by a Powered Air-Purifying Respirator (PAPR) equipped with an improperly sized or stretched-out loose-fitting facepiece using constant and cyclic flow conditions. Improperly sized PAPR facepieces of two models as well as a stretched-out facepiece were tested. These facepieces were examined in two versions: with and without exhaust holes. Loose-fitting facepieces (size "large") were donned on a small manikin headform and challenged with sodium chloride (NaCl) aerosol particles in an exposure chamber. Four cyclic flows with mean inspiratory flows (MIFs) of 30, 55, 85, and 135 L/min were applied using an electromechanical Breathing Recording and Simulation System (BRSS). The manikin Fit Factor (mFF) was determined as the ratio of aerosol concentrations outside (Cout) to inside (Cin) of the facepiece, measured with a P-Trak condensation particle counter (CPC). Results showed that the mFF decreased exponentially with increasing MIF. The mFF values of the stretched-out facepiece were significantly lower than those obtained for the undamaged ones. Facepiece type and MIF were found to significantly affect the performance of the loose-fitting PAPR. The effect of the exhaust holes was less pronounced and depended on the facepiece type. It was concluded that an improperly sized facepiece might potentially offer relatively low protection (mFF250) at high to strenuous workloads. The testing was also performed at a constant inhalation flow to explore the mechanism of the particle-facepiece interaction. Results obtained with cyclic flow pattern were consistent with the data generated when testing the loose-fitting PAPR under constant flow conditions. The time-weighted average values of mFF calculated from the measurements conducted under the constant flow regime were capable of predicting the protection under cyclic flow regime. The findings suggest that program administrators need to equip employees with properly sized facepieces and remove stretched-out ones from workplace. Manufacturers should emphasize the importance of proper sizing with their user instructions.

The triboelectric charging of fungal spores was experimentally characterized during rebound and resuspension. A fungal spore source strength tester (FSSST) was used as a primary aerosol generator for spores of three fungal species and two powders (silicon carbide and silver). The critical velocity of rebound was determined using a variable nozzle area impactor (VNAI), and the charging state of particles after resuspension and rebound was measured using the FSSST, different impactor setups, electrometers, and optical particle counters. In the impactor setups and the FSSST, five different surface materials relevant for indoor environments were used (steel, glass, polystyrene, paper, and polytetrafluoroethylene). The critical velocity of rebound was determined to be 0.57 m/s for fungal spores, which is relatively low compared to silicon carbide and previous results for micron-sized aerosol particles. Based on the rebound impactor measurements, we were able to define the crucial parameters of charge t...

In this study, we characterized the concentration of heavy metals in PM2.5 in the community with e-waste dismantling, Guiyu, China and assessed potential public health risk associated with heavy metal composition of PM2.5 for local residents. Daily samples of PM2.5 were collected with Harvard Impactors on the roof of 3-story buildings from March 2012–April 2013 in Guiyu (n = 133) and seasonal samples were collected in a reference site, Haojiang (n = 33). The concentrations of PM2.5 mass and heavy metals were analyzed gravimetrically and by graphite furnace atomic absorption spectrometry, respectively. The geometric mean concentrations of PM2.5, Pb and Cd in Guiyu were higher than in the reference area (PM2.5: 49.9 µg m–3 vs. 37.6 , p 0.05; Mn: 17 ng m–3 vs. 16 ng m–3, p > 0.05). The metal concentrations in PM2.5 from Guiyu were also higher when compared to other Asian cities. We observed higher heavy metal concentrations during winter and spring than summer and fall. Human health risk assessment showed that the total potential cancer risk for both adults and children are higher than the safe acceptable range recommended by the US EPA. Furthermore, the carcinogenic and non-carcinogenic elements in PM2.5 pose higher public health risk to children than adults. The results indicate that air pollution emitted from informal e-waste recycling activities might be affecting the health of local residents, especially children.

This study was conducted to investigate the performance of a high-efficiency Heating, Ventilation and Air Conditioning (HVAC) filter and a top-of-the line Automotive Cabin Air (ACA) filter challenged with particles generated by the combustion of paper, wood, and plastic as well as with NaCl particles. The collection of submicron particles was examined under conditions representing two typical indoor air flow rates for the HVAC filter and two cabin fan control levels for the ACA filter. For the HVAC filter, almost all the collection efficiency values exceeded 80%; for the ACA filter, the collect efficiencies were much lower (＜ 40%) for all the tested aerosols and flow rates. Both filters demonstrated lower collection efficiency for combustion aerosols as compared to NaCl. This finding was consistent for all tested particle sizes and flow rates. The difference was always statistically significant in terms of the total efficiency (combining all sizes); however, the size-specific analysis of the differences revealed that the significance level varied with the particle size and flow rate. When tested under their operational flow conditions, the HVAC filter showed significantly better performance than the ACA filter. It was concluded that the filter performance characteristics of the HVAC and ACA filters obtained using well-established salt aerosol challenges may not accurately predict the performance of these filters against combustion aerosol particles. The difference was attributed to the interactions between the particles and filter fibers.

Filtering facepiece respirators (FFRs) are commonly worn by first responders, first receivers and other exposed groups to protect against exposure to airborne particles, including those originated by combustion. Most of these FFRs are NIOSH-certified (e.g., N95-type) based on the performance testing of their filters against charge-equilibrated aerosol challenges, e.g., NaCl. However, it has not been examined if the filtration data obtained with the NaCl-challenged FFR filters adequately represent the protection against real aerosol hazards such as combustion particles. A filter sample of N95 FFR mounted on a specially designed holder was challenged with NaCl particles and three combustion aerosols generated in a test chamber by burning wood, paper and plastic. The concentrations upstream (C(up)) and downstream (C(down)) of the filter were measured with a TSI P-Trak condensation particle counter and a Grimm Nanocheck particle spectrometer. Penetration was determined as (C(down)/C(up)) ×100%. Four test conditions were chosen to represent inhalation flows of 15, 30, 55 and 85 L/min. Results showed that the penetration values of combustion particles were significantly higher than those of the “model” NaCl particles (p < 0.05), raising a concern about applicability of the N95 filters performance obtained with the NaCl aerosol challenge to protection against combustion particles. Aerosol type, inhalation flow rate and particle size were significant (p < 0.05) factors affecting the performance of the N95 FFR filter. In contrast to N95 filters, the penetration of combustion particles through R95 and P95 FFR filters (were tested in addition to N95) were not significantly higher than that obtained with NaCl particles. The findings were attributed to several effects, including the degradation of an N95 filter due to hydrophobic organic components generated into the air by combustion. Their interaction with fibers is anticipated to be similar to those involving “oily” particles. The findings of this study suggest that the efficiency of N95 respirator filters obtained with the NaCl aerosol challenge may not accurately predict (and rather overestimate) the filter efficiency against combustion particles.

The present pilot study investigated the penetration of ultrafine particles originated by combustion of different materials into elastomeric half-mask respirators equipped with two P100 filters. We determined the Simulated Workplace Protection Factor (SWPF) for 11 firefighters wearing elastomeric half-mask respirators and performing activities simulating those conducted during fire overhaul operations. The tests were performed in a controlled laboratory setting. A newly-developed battery-operated Portable Aerosol Mobility Spectrometer (PAMS) was used to measure size-resolved aerosol particle concentrations outside (C(out)) and inside (Cin) of an air-purifying respirator donned on a firefighter, and the SWPF was calculated as C(out)/C(in). Based on the total aerosol concentration, the "total" SWPF ranged from 4,222 (minimum) to 35,534 (maximum) with values falling primarily in a range from 11,171 (25 percentile) to 26,604 (75 percentile) and a median value being ≈15,000. This is consistent with the recently reported fit factor (FF) data base.((1)) The size-resolved SWPF data revealed a dependency on the particle size. It was concluded that a portable device such as PAMS can be used on firefighters during overhaul operations (as well as on other workers wearing elastomeric half-mask respirators) to monitor the aerosol concentrations in real time and ultimately help prevent overexposure.

Electronic waste (e-waste) generation is increasing worldwide, and its management becomes a significant challenge because of the many toxicants present in electronic devices. The U.S. is a major producer of e-waste, although its management practice and policy regulation are not sufficient to meet the challenge. We reviewed e-waste generation, current management practices and trends, policy challenges, potential health impact, and toxicant exposure prevention in the U.S. A large amount of toxic metals, flame retardants, and other persistent organic pollutants exist in e-waste or can be released from the disposal of e-waste (e.g., landfill, incineration, recycling). Landfill is still a major method used to dispose of obsolete electronic devices, and only about half of the states have initiated a landfill ban for e-waste. Recycling of e-waste is an increasing trend in the past few years. There is potential, however, for workers to be exposed to a mixture of toxicants in e-waste and these exposures should be curtailed. Perspectives and recommendations are provided regarding managing e-waste in the U.S. to protect public health, including enacting federal legislation, discontinuing landfill disposal, protecting workers in recycling facilities from toxicant exposure, reducing toxicant release into the environment, and raising awareness of this growing environmental health issue among the public.

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.

Both Streptomyces species and mold species have previously been isolated from moisture-damaged building materials; however, an association between these two groups of microorganisms in indoor environments is not clear. In this study, we used a culture-independent method, PCR-denaturing gradient gel electrophoresis (PCR-DGGE), to investigate the composition of the Streptomyces community in house dust. Twenty-three dust samples each from two sets of homes categorized as high-mold and low-mold based on mold-specific quantitative PCR analysis were used in the study. Taxonomic identification of prominent bands was performed by cloning and sequencing. Associations between DGGE amplicon band intensities and home mold status were assessed using univariate analyses as well as multivariate recursive partitioning (decision trees) to test the predictive value of combinations of bands intensities. In the final classification tree, a combination of two bands was significantly associated with mold status of the home (p = 0.001). The sequence corresponding to one of the bands in the final decision tree matched a group of Streptomyces species that included Streptomyces coelicolor and Streptomyces sampsonii, both of which have been isolated from moisture-damaged buildings previously. The closest match for the majority of sequences corresponding to a second band consisted of a group of Streptomyces species that included Streptomyces hygroscopicus, an important producer of antibiotics and immunosuppressors. Taken together, the study showed that DGGE can be a useful tool for identifying bacterial species that may be more prevalent in mold-damaged buildings.

Green building materials are becoming more popular. However, little is known about their ability to support or limit microbial growth. The growth of fungi was evaluated on five building materials. Two green, two conventional building materials and wood as a positive control were selected. The materials were inoculated with Aspergillus versicolor, Cladosporium cladosporioides and Penicillium brevicompactum, in the absence and presence of house dust. Microbial growth was assessed at four different time points by cultivation and determining fungal biomass using the N-acetylhexosaminidase (NAHA) enzyme assay. No clear differences were seen between green and conventional building materials in their susceptibility to support microbial growth. The presence of dust, an external source of nutrients, promoted growth of all the fungal species similarly on green and conventional materials. The results also showed a correlation coefficient ranging from 0.81 to 0.88 between NAHA activity and culturable counts. The results suggest that the growth of microbes on a material surface depends on the availability of organic matter rather than the classification of the material as green or conventional. NAHA activity and culturability correlated well indicating that the two methods used in the experiments gave similar trends for the growth of fungi on material surfaces.

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) 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.

BACKGROUND: Breathing frequency (breaths/min) differs among individuals and levels of physical activity. Particles enter respirators through two principle penetration pathways: faceseal leakage and filter penetration. However, it is unknown how breathing frequency affects the overall performance of N95 filtering facepiece respirators (FFRs) and surgical masks (SMs) against viral particles, as well as other health-relevant submicrometer particles. METHODS: A FFR and SM were tested on a breathing manikin at four mean inspiratory flows (MIFs) (15, 30, 55 and 85 L/min) and five breathing frequencies (10, 15, 20, 25 and 30 breaths/min). Filter penetration (P(filter)) and total inward leakage (TIL) were determined for the tested respiratory protection devices against sodium chloride (NaCl) aerosol particles in the size range of 20 to 500 nm. “Faceseal leakage-to-filter” (FLTF) penetration ratios were calculated. RESULTS: Both MIF and breathing frequency showed significant effects (p1, suggesting that the faceseal leakage was the primary particle penetration pathway at various breathing frequencies. CONCLUSIONS: Breathing frequency is another factor (besides MIF) that can significantly affect the performance of N95 FFRs, with higher breathing frequencies increasing TIL. No consistent trend of increase or decrease of TIL with either MIF or breathing frequency was observed for the tested SM. To potentially extend these findings beyond the manikin/breathing system used, future studies are needed to fully understand the mechanism causing the breathing frequency effect on the performance of respiratory protection devices on human subjects.

The study objective was to examine how the changes in outdoor concentration of traffic-related aerosol at schools occurring due to an anti-idling campaign affect the indoor aerosol concentration. Four urban public schools featuring different average numbers of school buses and cars and located at different distances from major urban traffic arteries were selected in Cincinnati (Ohio, USA). For each school, the indoor and outdoor air monitoring was conducted before and after the implementation of anti-idling campaign. Additionally, the ambient air was monitored at four “community” sites representing the background aerosol. The PM2.5 samples were collected and subjected to gravimetric, carbon and elemental analysis. The outdoor concentrations of PM2.5 and its relevant elemental constituents were consistent with the data reported in previous studies. Following the anti-idling campaign, the outdoor concentration of most elements decreased at two schools although only a fraction showed statistically significant changes. After accounting for the background aerosol changes, the positive impact of the anti-idling campaign was demonstrated only for one school – with the most intense local traffic. For this school, reduction of the outdoor elemental concentrations was followed by a decrease in the corresponding indoor concentrations (R2 = 0.47, p < 0.05). The data suggests that in cases when traffic emission is the dominant pollution source in the school vicinity, the changes in outdoor air quality associated with the anti-idling campaign are capable of reducing the children exposure to traffic aerosols inside the schools.

Few studies have addressed the potential changes in particulate matter (PM) exposure occurring in major metropolitan areas over substantial time periods, e.g., 5 or 10 years. The present study examined changes in the PM_(2.5) concentration and elemental composition between two monitoring campaigns carried out in 2002-2005 and 2010-2011 within the Greater Cincinnati area (USA). This area is recognized for high volume of diesel truck traffic (about 10 million trucks annually on regional freeways). The 24-hour filter samples were collected at four sites. General linear models were used to examine differences between the two data sets for elemental carbon (EC), organic carbon (OC), and EC/OC. The comparison was extended to the concentrations of PM_(2.5) and its relevant elemental constituents. At one site, which was previously identified as a particularly hot spot for traffic/diesel air pollution, the concentrations of most traffic related elements as well as EC and EC/OC ratio significantly decreased (p ＜ 0.05) between the two campaigns. No significant differences between carbon data generated in the two campaigns were observed at the other three monitoring stations. These findings did not depend on whether the comparison model accounted for wind speed and direction. The EC/OC determined in the recent campaign across all sites showed no significant differences between the Summer and Fall data but Winter values were significantly lower. The site with the highest traffic influence revealed no significant seasonal difference in PM_(2.5) but essentially all relevant elements showed significant seasonal variations between the Fall (higher) and Winter (lower). The findings suggest that air quality and engine exhaust control policies implemented between 2005 and 2010 have not produced significant changes in metropolitan traffic air pollution levels. However, the decreasing trends in PM_(2.5), Ti, V, Mn, Fe, Zn, Br, and Pb, EC, OC, and EC/OC may become sustainable over a longer time.

Background: There is increasing concern about the potential effects of traffic-related air pollution (TRAP) on the developing brain. The impact of TRAP exposure on childhood behavior is not fully understood because of limited epidemiologic studies. Objective: We explored the association between early-life exposure to TRAP using a surrogate, elemental carbon attributed to traffic (ECAT), and attention deficit/hyperactivity disorder (ADHD) symptoms at 7 years of age. Methods: From the Cincinnati Childhood Allergy and Air Pollution Study (CCAAPS) birth cohort we collected data on exposure to ECAT during infancy and behavioral scores at 7 years of age. Children enrolled in CCAAPS had at least one atopic parent and a birth residence either 1,500 m from a major highway. Children were followed from infancy through 7 years of age. ECAT exposure during the first year of life was estimated based on measurements from 27 air sampling sites and land use regression modeling. Parents completed the Behavioral Assessment System for Children, 2nd Edition, when the child was 7 years of age. ADHD-related symptoms were assessed using the Hyperactivity, Attention Problems, Aggression, Conduct Problems, and Atypicality subscales. Results: Exposure to the highest tertile of ECAT during the child’s first year of life was significantly associated with Hyperactivity T-scores in the “at risk” range at 7 years of age, after adjustment [adjusted odds ratio (aOR) = 1.7; 95% CI: 1.0, 2.7]. Stratification by maternal education revealed a stronger association in children whose mothers had higher education (aOR = 2.3; 95% CI: 1.3, 4.1). Conclusions: ECAT exposure during infancy was associated with higher Hyperactivity scores in children; this association was limited to children whose mothers had more than a high school education.

OBJECTIVE: To investigate the effects of faceseal leakage, breathing flow and combustion material on the overall (none size-selective) penetration of combustion particles into P-100 half and full facepiece elastomeric respirators used by firefighters. METHODS: Respirators were tested on a breathing manikin exposed to aerosols produced by combustion of three materials (wood, paper, and plastic) in a room-size exposure chamber. Testing was performed using a single constant flow (inspiratory flow rate = 30 L/min) and three cyclic flows (mean inspiratory flow rates = 30, 85, and 135 L/min). Four sealing conditions (“unsealed”, “nose-only sealed”, “nose & chin sealed”, and “fully sealed”) were examined to evaluate the respirator faceseal leakage. The total aerosol concentration was measured inside (C(in)) and outside (C(out)) of the respirator using a condensation particle counter. The total penetration through the respirator was determined as a ratio of the two (P = C(in) / C(out)). RESULTS: Faceseal leakage, breathing flow type and rate, and combustion material were all significant factors affecting the performance of the half mask and full facepiece respirators. The efficiency of P-100 respirator filters met the NIOSH certification criteria (penetration ≤0.03%); it was not significantly influenced by the challenge aerosol and flow type, which supports the current NIOSH testing procedure utilizing a single challenge aerosol and a constant air flow. However, contrary to the NIOSH total inward leakage (TIL) test protocol assuming that the result is independent on the type of the tested aerosol, this study revealed that the challenge aerosol significantly affects the particle penetration through unsealed and partially sealed half mask respirators. Increasing leak size increased the total particle penetration. The findings of this study point to some limitations of the existing TIL test in predicting protection levels offered by half mask elastomeric respirators.

Water-damaged buildings can lead to fungal growth and occupant health problems. Green building materials, derived from renewable sources, are increasingly utilized in construction and renovations. However, the question as to what fungi will grow on these green compared to non-green materials, after they get wet, has not been adequately studied. By determining what fungi grow on each type of material, the potential health risks can be more adequately assessed. In this study, we inoculated green and non-green pieces of ceiling tile, composite board, drywall, and flooring with indoor dust containing a complex mixture of naturally occurring fungi. The materials were saturated with water and incubated for two months in a controlled environment. The resulting fungal microbiomes were evaluated using ITS amplicon sequencing. Overall, the richness and diversity of the mycobiomes on each pair of green and non-green pieces were not significantly different. However, different genera dominated on each type of material. For example, Aspergillus spp. had the highest relative abundance on green and non-green ceiling tiles and green composite boards, but Peniophora spp. dominated the non-green composite board. In contrast, Penicillium spp. dominated green and non-green flooring samples. Green gypsum board was dominated by Phialophora spp. and Stachybotrys spp., but non-green gypsum board by Myrothecium spp. These data suggest that water-damaged green and non-green building materials can result in mycobiomes that are dominated by fungal genera whose member species pose different potentials for health risks.

Sampling for microbial determination can be conducted by air sampling or by direct source evaluation techniques, such as bulk sampling, surface sampling, and dust sampling. The choice of a sampling method depends on the purpose of the sampling and the method for the subsequent sample analysis. Investigators should be aware of the pros and cons of the methods they are using.

Airborne fungi may contribute to the organic carbon (OC) content of particulate matter, which make them relevant to air pollution and climate change issues. This study aimed at assessing the contribution of fungal spores to the inhalable OC in indoor and outdoor environments in the Cincinnati metropolitan area. The contribution was calculated assuming that carbon content per fungal spore was 13 pg (derived from a report from Austria). Air samples were collected from 18 homes during summer. At each site, two air samples were simultaneously taken using Button Personal Inhalable Samplers for 24 hours. One sample was subjected to the total fungi enumeration and the other one was analyzed for OC with ThermalOptical Transmittance technique. A (1-3)-β-d-glucan analysis was also conducted for indoor air samples using Limulus Amebocyte Lysate assay. Additionally, a questionnaire survey was performed on the various factors that might affect the indoor aerosol OC level. The total OC concentration ranged from 0.5 to 19.0 μg/m 3 in outdoor air and from 0 to 36.2 3 in indoor air. The concentration of OC originating from fungal spores ranged from 3.8 to 958.4 ng/m 3 in outdoor air while the respective range in indoor air was 0.8 to 351.2 ng/m 3 . The (1-3)-β-d-glucan was present indoors at levels ranging from 82.1 to 41,910 pg/m 3 . In contrast to studies performed in Austria, Australia and Britain, we found that fungal spores contribute rather little to the local outdoor OC. This could be due to different sampling instruments used for fungal spore sampling and regional differences in fungal spore concentrations. Even smaller contribution of fungal spores was found for indoor OC (average of 0.21%). Statistical analysis revealed that cigarette smoking was a significant factor for the indoor organic carbon level. The results indicate that smoking contributes to the indoor OC level more significantly than fungi.

Fungi are ubiquitous in indoor and outdoor environments and have been associated with respiratory disease including childhood and adult asthma. A growing body of evidence from human and animal studies has revealed a link between fungal exposure, especially indoor fungal exposure, with asthma initiation, persistence, and exacerbation. Despite the overwhelming evidence linking mold exposure and asthma, the mechanistic basis for the association has remained elusive. It is now clear that fungi need not be intact to impart negative health effects. Fungal components and fungal fragments are biologically active and contribute to asthma development and severity. Recent mechanistic studies have demonstrated that fungi are potent immunomodulators and have powerful effects on asthma independent of their potential to act as antigens. This paper will review the connection between fungal exposure and asthma with a focus on the immunological mechanisms underlying this relationship.

Manganese (Mn) is both essential element and neurotoxicant. Exposure to Mn can occur from various sources and routes. Structural equation modeling was used to examine routes of exposure to Mn among children residing near a ferromanganese refinery in Marietta, Ohio. An inhalation pathway model to ambient air Mn was hypothesized. Data for model evaluation were obtained from participants in the Communities Actively Researching Exposure Study (CARES). These data were collected in 2009 and included levels of Mn in residential soil and dust, levels of Mn in children's hair, information on the amount of time the child spent outside, heat and air conditioning in the home and level of parent education. Hair Mn concentration was the primary endogenous variable used to assess the theoretical inhalation exposure pathways. The model indicated that household dust Mn was a significant contributor to child hair Mn (0.37). Annual ambient air Mn concentration (0.26), time children spent outside (0.24) and soil Mn (0.24) significantly contributed to the amount of Mn in household dust. These results provide a potential framework for understanding the inhalation exposure pathway for children exposed to ambient air Mn who live in proximity to an industrial emission source.

The main objective of the grant was to develop and characterize new materials that are useful as energetic components while releasing highly potent biocidal combustion products. These materials are intended to replace or supplement metal fuel powders in the current energetic formulations. The goal is to make them stable, easy to handle, and compatible with the other formulation components. Beyond the material development and characterization scope, this study aimed at extensively testing the biocidal efficiency of the newly-prepared compositions against stress-resistant aerosolized bacterial endospores serving as surrogates for Bacillus anthracis.

Informal recycling of e-waste and the resulting heavy metal pollution has become a serious burden on the ecosystem in Guiyu, China. In this investigation, we evaluated the trace metal concentration of community soil and road dust samples from 11 locations in Guiyu and 5 locations (consisting of residential areas, kindergarten/school, and farm field) in a reference area using graphite furnace atomic absorption spectrophotometer. The study spanned four seasons, 2012–2013, with a view to assess the risk associated with e-waste recycling in the study area. The concentrations of Pb, Cd, Cr, and Mn were 448.73, 0.71, 63.90, and 806.54 mg/kg in Guiyu soil and 589.74, 1.94, 69.71, and 693.74 mg/kg, in the dust, respectively. Pb and Cd values were significantly higher (P ≤ 0.05) than the reference area, and the mixed model analysis with repeated seasonal measurements revealed soil Pb and Cd levels that were 2.32 and 4.34 times, while the ratios for dust sample were 4.10 and 3.18 times higher than the reference area. Contamination factor, degree of contamination, and pollution load index indicated that all sampling points had a high level of metal contamination except farm land and kindergarten compound. The cumulative hazard index of Pb, Cd, Cr, and Mn for children in exposed area was 0.99 and 1.62 for soil and dust, respectively, suggesting non-cancer health risk potential. The significant accumulation of trace metals in the e-waste recycling area predisposes human life, especially children, to a potentially serious health risk.

Manganese (Mn) is ubiquitous in the environment and essential for normal growth and development, yet excessive exposure can lead to impairments in neurological function. This study modeled ambient Mn concentrations as an alternative to stationary and personal air sampling to assess exposure for children enrolled in the Communities Actively Researching Exposure Study in Marietta, OH. Ambient air Mn concentration values were modeled using US Environmental Protection Agency’s Air Dispersion Model AERMOD based on emissions from the ferromanganese refinery located in Marietta. Modeled Mn concentrations were compared with Mn concentrations from a nearby stationary air monitor. The Index of Agreement for modeled versus monitored data was 0.34 (48 h levels) and 0.79 (monthly levels). Fractional bias was 0.026 for 48 h levels and - 0.019 for monthly levels. The ratio of modeled ambient air Mn to measured ambient air Mn at the annual time scale was 0.94. Modeled values were also time matched to personal air samples for 19 children. The modeled values explained a greater degree of variability in personal exposures compared with time-weighted distance from the emission source. Based on these results modeled Mn concentrations provided a suitable approach for assessing airborne Mn exposure in this cohort.

OBJECTIVES The first objective of this study was to evaluate the penetration of particles generated from combustion of plastic through National Institute for Occupational Safety and Health (NIOSH)-certified N95 filtering facepiece respirators (FFRs) using a manikin-based protocol and compare the data to the penetration of NaCl particles. The second objective was to investigate the effect of relative humidity (RH) on the filtration performance of N95 FFRs. METHODS Two NIOSH-certified N95 FFRs (A and B) were fully sealed on a manikin headform and challenged with particles generated by combustion of plastic and NaCl particles. The tests were performed using two cyclic flows [with mean inspiratory flow (MIF) rates = 30 and 85 l min(-1), representing human breathing under low and moderate workload conditions] and two RH levels (≈20 and ≈80%, representing dry and moderately humid air). The total and size-specific particle concentrations inside (C in) and outside (C out) of the respirators were measured with a condensation particle counter and an aerosol size spectrometer. The penetration values (C in/C out) were calculated after each test. RESULTS The challenge aerosol, RH, MIF rate, and respirator type had significant (P < 0.05) effects on the performance of the manikin-sealed FFR. Its efficiency significantly decreased when the FFR was tested with plastic combustion particles compared to NaCl aerosols. For example, at RH ≈80% and MIF = 85 l min(-1), as much as 7.03 and 8.61% of combustion particles penetrated N95 respirators A and B, respectively. The plastic combustion particles and gaseous compounds generated by combustion likely degraded the electric charges on fibers, which increased the particle penetration. Increasing breathing flow rate or humidity increased the penetration (reduced the respirator efficiency) for all tested aerosols. The effect of particle size on the penetration varied depending on the challenge aerosol and respirator type. It was observed that the peak of the size distribution of combustion particles almost coincided with their most penetrating particle size, which was not the case for NaCl particles. This finding was utilized for the data interpretation. CONCLUSIONS N95 FFRs have lower filter efficiency when challenged with contaminant particles generated by combustion, particularly when used under high humidity conditions compared to NaCl particles.

Accidental release of biological agents from a bioweapon facility may contaminate large areas, possibly causing disastrous environmental consequences. To address this issue, novel halogen-containing reactive materials are being designed with the added capability to inactivate viable airborne microorganisms. This study determined the efficiency of combustion products of such materials to inactivate aerosolized bacteria and viruses. Spores of Bacillus atrophaeus and MS2 viruses dispersed in dry air were exposed for subsecond time intervals to hydrocarbon flames seeded with different reactive powders so that bioaerosol particles interacted with the combustion products in a controlled high-temperature environment. The experiments were designed to quantify differences in the biocidal effects of different reactive material powders including Al and Mg, a B•Ti nanocomposite, an 8Al•MoO(3) nanothermite, and a novel Al•I(2) nanocomposite. Compared to pure hydrocarbon flame, powder-seeded flame (with no iodine) produced about an order of magnitude greater inactivation of bacterial spores. The iodine-containing material increased the spore inactivation by additional 2 orders of magnitude. The aerosolized MS2 viruses (generally not as stress-resistant as spores) were fully inactivated when exposed to combustion of either the iodinated or noniodinated powders. Overall, the study suggests a great biocidal potential of combustion products generated by novel iodine-containing nanocomposite materials.

Mold exposures may contribute to the development of asthma, but previous studies have lacked a standardized approach to quantifying exposures.To determine whether mold exposures at the ages of 1 and/or 7 years were associated with asthma at the age of 7 years.This study followed up a high-risk birth cohort from infancy to 7 years of age. Mold was assessed by a DNA-based analysis for the 36 molds that make up the Environmental Relative Moldiness Index (ERMI) at the ages of 1 and 7 years. At the age of 7 years, children were evaluated for allergic sensitization and asthma based on symptom history, spirometry, exhaled nitric oxide, and airway reversibility. A questionnaire was administered to the parent regarding the child's asthma symptoms and other potential cofactors.At the age of 7 years, 31 of 176 children (18%) were found to be asthmatic. Children living in a high ERMI value (≥5.2) home at 1 year of age had more than twice the risk of developing asthma than those in low ERMI value homes (5.2) (adjusted odds ratio [aOR], 2.6; 95% confidence interval [CI], 1.10-6.26). Of the other covariates, only parental asthma (aOR, 4.0; 95% CI, 1.69-9.62) and allergic sensitization to house dust mite (aOR, 4.1; 95% CI, 1.55-11.07) were risk factors for asthma development. In contrast, air-conditioning at home reduced the risk of asthma development (aOR, 0.3; 95% CI, 0.14-0.83). A high ERMI value at 7 years of age was not associated with asthma at 7 years of age.Early exposure to molds as measured by ERMI at 1 year of age, but not 7 years of age, significantly increased the risk for asthma at 7 years of age.

Ventilation guidelines for airborne infection isolation rooms (AIIRs) are highly variable in different countries indicating lack of actual knowledge about the guidance needed. However, US guidelines for AIIRs are extensive and have been widely adopted outside the US. AIIR performance has also been evaluated in numerous studies. For a long time, the aim has mainly been to evaluate how well the existing AIIRs meet US guidelines. For historical reasons, mixing-type ventilation has been emphasised and attention has been paid to air exchange rates, although the use of auxiliary devices, such as portable room-air cleaners and ultraviolet germicidal irradiation systems, has also been examined. Recently, the scope of the investigations has been widened. The most crucial issue is to minimise the potential for disease transmission and prevent the escape of contaminated air from the AIIR. Airflow direction inside the AIIR is also important and AIIRs minimise air leakage to save energy. On the other hand, it has been observed that efficient containment can be achieved even by using simple and inexpensive construction by considering pressure differential and air flow patterns. Nevertheless, additional research is needed to assist hospitals with improving their preparedness to cope with the threat of pandemics by building and using effective AIIRs.

In addition to mold, indoor bioaerosols also contain bacterial components that may have implications for human health. Endotoxin is a cell wall component in Gram-negative bacteria present at varying levels indoors that has been found to have respiratory health implications. Streptomyces is a large genus of Gram-positive bacteria, and some species have been shown to produce inflammatory reactions in vitro and in vivo. The aim of this study was to determine predictors of streptomycetes levels in house dust and to compare the variation in streptomycetes levels with that in endotoxin levels. Dust was collected by floor vacuuming from 178 homes in the Cincinnati metropolitan area. Streptomycetes levels were measured by quantitative PCR, and endotoxin was assayed by the Limulus amebocyte lysate method. Associations between home characteristics and bacterial contaminants, expressed as concentration and load, were investigated through multiple regression analyses. The presence of two or more dogs was a strong predictor of both streptomycetes and endotoxin levels. Season of dust collection and levels of outdoor molds were predictors of streptomycetes but not endotoxin levels. In contrast, number of inhabitants was a significant predictor of endotoxin load only. Neither streptomycetes nor endotoxin levels were associated with metrics of moisture damage. Practical Implications This study adds to the understanding of the sources of bacterial contaminant in indoor environments. The results suggest that streptomycetes have mostly outdoor sources, whereas indoor sources are more important for endotoxin. The results also indicate that the presence of pets, particularly two or more dogs, is a strong source of bacterial contamination. In this study, neither streptomycetes nor endotoxin levels were significantly associated with metrics for moisture damage. Both endotoxin and streptomycetes levels may represent too large and diverse bacterial taxa to be consistent indicators of indoor moisture damage.

Inactivation of viable bioaerosol particles, especially stress-resistant microorganisms, has important implications for biodefense and air quality control. It has earlier been shown that the loss of viability of bacterial endospores due to exposure to dry heat is associated with mutational damage. Previous studies, however, used non-aerosolized spores, long exposure times, and moderately elevated temperatures. This study was designed to investigate the mechanism of inactivation of aerosolized Bacillus endospores exposed to high temperatures for sub-second time periods. Bioaerosol was tested in a continuous air flow chamber under two flow rates, 18 L/min and 36 L/min. The chamber had a cylindrical electric heating element installed along its axis. The estimated characteristic exposure temperature (T(exposure)) ranged from 164°C to 277°C (with an uncertainty of 21–26°C). To quantify mutational frequency, spores were cultivated after dry heat exposure on tryptic-soy agar and on antibiotic nalidixic acid media. Increases in the exposure temperature caused viability loss and increase in mutational frequency of the spore DNA. Significant association was found between the inactivation factor and the mutational frequency ratio (heat exposed versus non-exposed) with R(2) of 0.985 for both flow rates combined. The results suggest that mutational damage is involved in the causal chain of events leading to inactivation of aerosolized endospores exposed to heat for sub-second time periods.

Objectives: Concentrations of microbial cell wall components such as endotoxin and β-D-glucan in airborne submicrometer particle size fraction (PM1, defined as particles with median aerodynamic diameter, da ≤ 1 μm) have not been well characterized. In this study, airborne concentrations of endotoxin and β-D-glucan among different size fractions were quantified in two distinctly different environments: farms and homes. Effect of microbial source (farm type for farms and mold damage for homes) on size-fractionated concentrations was investigated. Methods: Airborne endotoxin and β-D-glucan were collected on 7 farms and 184 suburban homes using NIOSH twostage sampler, a cyclone air sampler that fractionates airborne particles into three size fractions: ≤ 1 μm, 1–1.8 μm and ≥ 1.8 μm. Results: Geometric means (geometric standard deviations) of airborne total endotoxin concentration on farms and in homes were 1.20 × 10 4 (7.57) EU/m 3 and 2.67 (3.82) EU/m 3 , respectively. Similar values of airborne total β-D-glucan concentrations were 1.80 × 10 3 (152.88) ng/m 3 and 1.91 (2.83) ng/m 3 , respectively. Relative proportions of PM1 endotoxin, however, were significantly higher (p < 0.001) in home samples (7.9%) than in farm samples (0.3%). Likewise, the proportion of PM1 β-D-glucan was significantly higher (p < 0.001) in homes (28.2% vs. 2.3%). Farm type significantly influenced concentrations of PM1 β-D-glucan (p < 0.05) and total β-D-glucan (p < 0.001). Conclusions: The results of this study demonstrate higher proportions of PM1 endotoxin and β-D-glucan in homes compared to farms. These data further emphasize the importance of conducting size-selective air sampling for microbial exposure assessment in homes.

Objectives: Thisstudyinvestigatedparticle-size-selective protection factors (PFs) offourmodels ofN95filteringfacepiece respirators(FFRs) thatpassedandfailedfittesting. Particle sizeranges wererepresentativeofindividualvirusesandbacteria(aerodynamicdiameterda 50.04‐1.3 mm). Methods: Standard respirator fit testing was followed by particle-size-selective measurement of PFs while subjects wore N95 FFRs in a test chamber. PF values obtained for all subjects were then compared to those obtained for the subjects who passed the fit testing. Results: Overall fit test passing rate for all four models of FFRs was 67%. Of these, 29% had PFs

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

In this investigation, an experimental facility was developed for quantifying the inactivation of viable bioaerosol particles in a controlled axially heated air flow. The tests were conducted with Bacillus subtilis var. niger endospores. The thermal inactivation of aerosolized spores was measured based on the loss of their culturability that resulted from a short-term exposure to air temperatures ranging from ∼150 to >1000 °C. The cross-sectional and longitudinal temperature profiles in the test chamber were determined for different heating and flow conditions. The characteristic exposure temperature ( T e ) was defined using a conservative approach to assessing the spore inactivation. Experimentally determined inactivation factors ( IF ) were corrected to account for the temperature profiles in the axially heated air flow. The reported IF -values serve as the lower approximation of the actual inactivation. Two data sets obtained at different flow rates, Q =18 and 36 L min −1 , represent different exposure conditions. In both cases, the thermal exposure of aerosolized spores produced no effect or only a moderate inactivation when the T e remained below ∼200 °C for 18 L min −1 and ∼250 o C for 36 L min −1 . The IF -values increased exponentially by about four orders of magnitude as the temperature rose by 150 °C. Depending on the flow rate, IF exceeded ∼10 4 at T e >320 °C ( Q =18 L min −1 ) or >360 °C ( Q =36 L min −1 ). At T e ≈375–400 °C, the spore inactivation obtained at both flow rates reached the limit of quantification established in this study protocol, which translates to approximately 99.999% viability loss. The findings were attributed primarily to the heat-induced damage of DNA and denaturation of essential proteins. Up to a certain level of the thermal exposure, these damages are repairable; however, the self-repair capability diminishes as the heat rises and then the damage becomes totally irreversible. The data generated in this study provide an important reference point for thermal inactivation of stress-resistant spores in various biodefense/counterterrorism and air quality control applications.

Though studies have investigated the association between air pollution and respiratory health outcomes in children, few have focused on night cough. The study objective was to simultaneously evaluate family factors (i.e., race, gender, maternal and paternal asthma, and breastfeeding), health (allergen sensitization and wheezing symptoms), home factors (dog, cat, mold, endotoxin, and dust mite), and other environmental exposures (traffic exhaust and second-hand tobacco smoke) for associations with recurrent dry night cough (RNC) during early childhood. A structural equation model with repeat measures was developed assessing RNC at ages one, two, and three. The prevalence of RNC was relatively large and similar at ages, one, two, and three at 21.6%, 17.3%, and 21.1%, respectively. Children exposed to the highest tertile of traffic exhaust had an estimated 45% increase in risk of RNC compared with children less exposed (adjusted OR 1.45, 95% CI: 1.09, 1.94). Also, wheezing was associated with a 76% higher risk of RNC (adjusted OR 1.76, 95% CI: 1.36, 2.26). A protective trend for breastfeeding was found with a 27% reduction in risk associated with breastfeeding (adjusted OR 0.73, 95% CI: 0.53, 1.01). No other factors were significant. These results suggest that traffic exhaust exposure may be a risk factor for night cough in young children.

Inactivation of airborne microorganisms due to thermal or chemical air treatment has gained considerable attention. Destruction of aerosolized biothreat agents in environments containing combustion products is particularly relevant to military and counterterrorism situations because some pathogens may survive an explosion or fire in a bio-weapon facility and be dispersed in the atmosphere. Energetic materials with biocidal properties are being sought to effectively inactivate stress-resistant aerosolized microorganisms. Consequently, appropriate methods are needed to test these materials. We designed and built a state-of-the-art experimental facility and developed protocols for assessing the survival of aerosolized microorganisms exposed to combustion. The facility uses a continuous-flow design and includes an aerosolization unit, a test (combustion) chamber, and a measurement system for bioaerosol particles exposed to combustion environments for sub-second time intervals. The experimental method was tested with Bacillus endospores. We assessed the inactivation of aerosolized spores exposed to a gaseous hydrocarbon flame and to combustion of aluminum-based energetic composites (including a novel iodine-containing filled nanocomposite material). Two combustion configurations were evaluated – a vertical strand containing a consolidated material and a specially designed burner in which a fuel powder is fed into a gaseous hydrocarbon flame. It was established that the bioaerosol inactivation may be overestimated due to exposure of spores on collection filters to the combustion products throughout the test. The overestimation can be mitigated by reducing the collection time and minimizing the formation of soot. The experimental facility and method developed in this study enables evaluating effects caused by biocidal products during combustion. The present version of the set-up provides the capability of detecting inactivation levels of ~2.2 × 10 5 (over five-log viability reduction) its further design modifications can potentially enable measuring bioaerosol inactivation as high as ~10 7 . The method was utilized for establishing feasibility of the new iodine-containing material for microbial agent defeat applications. Keyword: Bioaerosols; Combustion aerosols; Hazardous air pollutants.

Murine models demonstrate a synergistic production of reactive oxygen species on coexposure to diesel exhaust particles and endotoxin.It was hypothesized that coexposure to traffic-related particles and endotoxin would have an additive effect on persistent wheezing during early childhood.Persistent wheezing at age 36 months was assessed in the Cincinnati Childhood Allergy and Air Pollution Study, a high-risk birth cohort. A time-weighted average exposure to traffic-related particles was determined by applying a land-use regression model to the homes, day cares, and other locations where children spent time from birth through age 36 months. Indoor levels of endotoxin were measured from dust samples collected before age 12 months. The relationship between dichotomized (oror=75th percentile) traffic-related particle and endotoxin exposure and persistent wheezing, controlling for potential covariates, was examined.Persistent wheezing at age 36 months was significantly associated with exposure to increased levels of traffic-related particles before age 12 months (OR = 1.75; 95% confidence interval, 1.07-2.87). Coexposure to endotoxin had a synergistic effect with traffic exposure on persistent wheeze (OR = 5.85; 95% confidence interval, 1.89-18.13) after adjustment for significant covariates.The association between traffic-related particle exposure and persistent wheezing at age 36 months is modified by exposure to endotoxin. This finding supports prior toxicological studies demonstrating a synergistic production of reactive oxygen species after coexposure to diesel exhaust particles and endotoxin. The effect of early versus later exposure to traffic-related particles, however, remains to be studied because of the high correlation between exposure throughout the first 3 years of life.

The protection level offered by filtering facepiece particulate respirators and face masks is defined by the percentage of ambient particles penetrating inside the protection device. There are two penetration pathways: (1) through the faceseal leakage, and the (2) filter medium. This study aimed at differentiating the contributions of these two pathways for particles in the size range of 0.03-1 microm under actual breathing conditions. One N95 filtering facepiece respirator and one surgical mask commonly used in health care environments were tested on 25 subjects (matching the latest National Institute for Occupational Safety and Health fit testing panel) as the subjects performed conventional fit test exercises. The respirator and the mask were also tested with breathing manikins that precisely mimicked the prerecorded breathing patterns of the tested subjects. The penetration data obtained in the human subject- and manikin-based tests were compared for different particle sizes and breathing patterns. Overall, 5250 particle size- and exercise-specific penetration values were determined. For each value, the faceseal leakage-to-filter ratio was calculated to quantify the relative contributions of the two penetration pathways. The number of particles penetrating through the faceseal leakage of the tested respirator/mask far exceeded the number of those penetrating through the filter medium. For the N95 respirator, the excess was (on average) by an order of magnitude and significantly increased with an increase in particle size (p0.001): approximately 7-fold greater for 0.04 microm, approximately 10-fold for 0.1 microm, and approximately 20-fold for 1 microm. For the surgical mask, the faceseal leakage-to-filter ratio ranged from 4.8 to 5.8 and was not significantly affected by the particle size for the tested submicrometer fraction. Facial/body movement had a pronounced effect on the relative contribution of the two penetration pathways. Breathing intensity and facial dimensions showed some (although limited) influence. Because most of the penetrated particles entered through the faceseal, the priority in respirator/mask development should be shifted from improving the efficiency of the filter medium to establishing a better fit that would eliminate or minimize faceseal leakage.

Characterizing the variation in bioaerosol concentrations is important for the estimation of health effects associated with bioaerosols and planning exposure assessment strategies. This investigation was conducted in order to develop a better understanding of exposure to fungal spores, pollen, and (1→3)-β-d-glucan, by determining the variations of their concentrations between and within homes. In the study, 24-h air sampling was performed on five consecutive days in four Cincinnati area homes. The samples (a total of 160) were taken simultaneously in four different rooms inside each home and at four different outside locations near the home using Button Personal Inhalable Aerosol Samplers. The relative sizes of the between- and within-home variability to the total variability were calculated for each outcome. The relative sizes of the between- and within-home variability in indoor air ranged from 0.10 to 0.52 and 0.09 to 0.10, respectively. For outdoor air, the between- and within-home variability ranged from 0.27 to 0.50 and 0.09 to 0.10, respectively. Thus, the ranges of within-home variability, both indoors and outdoors, were much less than the variability between different homes. The results suggest that, if long-term sampling methods are employed to characterize the bioaerosol exposure for a population, the sampling should be repeated in a larger number of homes as an alternative to replicate sampling in a fewer number of homes. When characterizing exposure within one home, the sampling should be repeated in different rooms, rather than repeating it on different days.

Lime treatment has been used in contaminated sediment management activities for many purposes such as dewatering, improvement of physical properties, and reducing contaminant mobility. Exothermic volatilization of volatile organic compounds from lime-treated sediment is well known, but potential aerosolization of bioaerosol components has not been evaluated. A physical model of a contaminated sediment treatment and airborne transport process and an experimental protocol were developed to identify specific bioaerosol components (bacteria, fungi, cell structural components, and particles) that may be aerosolized and transported. Key reaction variables (amount of lime addition, rate of lime addition, mixing energy supplied) that may affect the aerosolization of bioaerosol components were evaluated. Lime treatment of a sediment contaminated with heavy metals, petroleum-based organics, and microorganisms increased the sediment pH and solids content. Lime treatment reduced the number of water-extractable bacteria and fungi in the sediment from approximately 10(6) colony-forming units (CFU) x mL(-1) to less than the detection limit of 10(3) CFU x mL(-1). This reduction was seen immediately for bacteria and within 21 days for fungi. Lime treatment immediately reduced the amount of endotoxin in the sediment, but the effects of lime treatment on beta-D-glucan could not be determined. The temperature of the treated sediment was linearly related to the amount of lime added within the range of 0-25%. Bacteria were aerosolized during the treatment trials, but there was no culturable evidence of aerosolization of fungi, most likely because of either their particular growth stage or relatively larger particle size that reduced their aerosolization potential and their collection into the impingers. Nonbiological particles, endotoxin, and beta-D-glucan were not detected in air samples during the treatment trials. The amount of lime added to the reaction beaker and the relative amount of mixing energy supplied to the reaction significantly affected the aerosolization ratio of bacteria (amount of aerosolized bacteria divided by the amount of bacteria in untreated sediment) from the reaction beaker. The rate of lime addition did not significantly affect the aerosolization ratio of bacteria. The aerosolization results suggest that exposure to bacteria is possible with sediment treatment activities, but the hazard level could not be determined because speciation of the aerosolized bacteria for pathogen identification was not performed, and health and safety standards and criteria for bioaerosol components have not been developed. Quantitative scaling analysis and whether the system represents actual environmental conditions were not studied.

Aerosolization of bacteriophage MS2 virions by nebulization and charge-reduced electrospray were compared during testing of three filter media. Sample swatches were taken from a surgical mask, N95 filtering-facepiece respirator (FFR), and N100 FFR for use in repeated, short-duration (15 min) penetration tests with bacteriophage MS2 aerosolized by nebulizer and electrospray. Evaluated were (1) the virus suspension preparation protocol, (2) resulting particle size distribution, count stability, and count variability, and (3) the ability to generate culturable MS2 virions. While preparation of the electrospray bacteriophage suspension required additional purification and concentration steps and took more time than the nebulization protocol, it resulted in a much higher titer suspension. The nebulizer produced a polydisperse aerosol; conversely, the electrospray produced a relatively monodisperse aerosol with a count peak at the mobility size of the single virion. The nebulized aerosol particle count was 2.8 ...

Exposure to mold has been associated with exacerbation of asthma symptoms in children.To report how the presence of visible mold and exposure to (1-3)-beta-D-glucan in infancy affects the risk of asthma at the age of 3 years as defined by an Asthma Predictive Index (API).Visible mold was evaluated by means of home inspection. (1-3)-beta-D-glucan levels were measured in settled dust. Children were considered to be at high risk for asthma at later ages if they reported recurrent wheezing at the age of 3 years and met at least 1 of 3 major or 2 of 3 minor API criteria.Children aged 3 years with high visible mold in the home during infancy were 7 times more likely to have a positive API than were those with no visible mold (adjusted odds ratio [aOR], 7.1; 95% confidence interval [CI], 2.2-12.6). In contrast, at low (1-3)-beta-D-glucan levels (22 microg/g), children were at increased risk of a positive API (aOR, 3.4; 95% CI, 0.5-23.5), whereas those with high (1-3)-beta-D-glucan levels (133 microg/g) were at decreased risk (aOR, 0.6; 95% CI, 0.2-1.6). Of the other covariates, mother's smoking was the strongest significant risk factor for the future development of asthma based on a positive API (aOR, 4.4; 95% CI, 1.7-11.6).The presence of high visible mold and mother's smoking during infancy were the strongest risk factors for a positive API at the age of 3 years, suggesting an increased risk of asthma. High (1-3)-beta-D-glucan exposure seems to have an opposite effect on API than does visible mold.

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 (P0.001). 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.

PM2.5 mass concentration and its elemental composition were measured inside and outside of six houses located at a distance of approximately 30–300 m from major highways. To investigate the amount of traffic particles penetrating from indoor to the outdoor (I/O) environment, the data were analyzed by three-way factor method PARAFAC. The PM2.5 I/O ratio ranged from 0.5 ± 0.2 to 2.9 ± 1.2 in spring and from 0.7 ± 0.1 to 4.7 ± 6.9 in fall. The traffic component was very pronounced in the ambient air of the six houses. Although the distance from the highway and traffic intensity are generally important for assessing the indoor concentration of traffic-related aerosols, the data collected in this study suggest that – specifically for houses located in a close proximity to major highways – these two factors may not necessarily play the most important role in differentiating exposure levels between houses.

There are two methods available for the analysis of (1-3)-β-D-glucan: the Limulus Amebocyte Lysate assay (LAL) and the inhibition Enzyme Immunoassay (EIA). The aim of this study was to compare the accuracy and specificity of these two methods in detecting eight alpha and beta-glucan standards, and their sensitivity for the analysis of (1-3)-β- D-glucan content of common indoor fungal species and indoor dust samples. The results show that the LAL assay is more accurate, specific, and sensitive in measuring linear and branched β-D-glucans than the EIA. The greatest LAL-analyzed (1-3)-β-D-glucan content per spore (241 pg/spore) was found with E. nigrum, which also had the largest spore size (28 μm). The biomass-normalized (1-3)-β-D-glucan content of fungal spores from pure cultures was within similar range with the two assays but no correlation was found between the results from the two assays. In contrast, there was a significant correlation between the EIA and LAL-measured (1-3)-β-D-glucan concentrations (μg/m2 of floor area) in field dust samples.

The feasibility of a novel testing protocol that allows differentiating between the physical (total) and viable bioaerosol penetrations through respirator filters was investigated. Three respirator models - two conventional N95 filtering-facepiece respirators (FFR) used as controls and one P95 iodinated polymer FFR with antimicrobial properties - were challenged with aerosolized MS2 bacteriophage virus. Physical [Physical) and viable (P viable ) filter penetrations were simultaneously measured with the FFR sealed on a manikin at a constant inhalation flow rate of 85 L/min. Separate testing was performed on specially-manufactured P95 filter swatches with (i) no iodinated resin additive and (ii) "high" amount of the additive to determine whether it influenced filtration behavior of the P95 respirator. Bioaerosol collection on the N95 FFR filters fell in the range consistent with previous studies featuring about 2% penetration for MS2 and a peak around -5%. The P95 iodinated polymer respirator was found to be highly efficient, attributed in part to the iodinated resin powder which in separate swatch tests was found to increase the filter collection efficiency. No statistically significant differences were observed between penetration values obtained for total and culturable viruses for the two control respirators. Similarly, no difference was observed for the iodinated respirator, which suggested that the microbial inactivation effect was of insufficient magnitude to be detected or was not present for viral particles that penetrated the filter. Possible "long-term" inactivation effect of the iodine-based additive on the viable viruses, which were captured on the filter over time, was beyond the scope of this study. The novel testing protocol appears to be an adequate tool for evaluating respirators designed to protect against bioaerosol particles. Further improvement may be considered with respect to the aerosolization method for viable microorganisms.