Culturable Fungal Concentrations Research Articles

On-site investigation of the concentrations and size distributions of bioaerosols in the underground garages

Bioaerosol concentrations and sizes in indoor environment are associated with human health. Among various indoor environments, the knowledge of the bioaerosol characteristics in underground garages remains unclear. In this study, both DAPI (4′,6-diamidino-2-phenylindole) staining and culturable methods were performed to determine the concentrations and size distributions of bioaerosols in two typical underground garages (an office building (UBOB) and a commercial building (UBCB)) in Xi'an, China. Results indicated that bioaerosol concentrations showed seasonal variations in two garages. The total bioaerosol concentrations were higher in summer (UBOB: (1.07 ± 0.29) ✕105 cells/m3; UBCB: (0.59 ± 0.23) ✕105 cells/m3) than winter (UBOB: (0.34 ± 0.17) ✕105 cells/m3; UGCB: (0.38 ± 0.15)✕105 cells/m3). Higher concentrations of bioaerosols were also found during the rush hour than other times due to the elevated traffic volumes. The spatial distribution of bioaerosols was relatively even for most sampling sites in two garages. Moreover, over 80% of airborne culturable fungi and over 65% of airborne culturable bacteria were in respirable size range (<4.7 μm). Importantly, airborne culturable fungal concentrations in two garages exceeded the proposed thresholds by the World Health Organization (WHO) (500 CFU/m3), with the exceeding standard rate (ESR) of 80.28% and 82.60%, respectively, at UGOB and UGCB, implying that necessary control measures should be taken to reduce microorganism contamination in the air of underground garages. The present results may provide the scientific basis for better understanding pollution characteristics of bioaerosols and formulating prevention and control measures in underground garages.

Distribution Characteristics and Health Effects of Bioaerosols in Spring over Xi'an City

A large amount of fluffy caktins appears in spring in Xi'an that may cause air pollution and lead to health risks such as asthma. In this study, bioaerosol, PM2.5, and fluffy catkins were collected from different sample points (traffic site and campus site) in Xi'an in spring. The variations in bioaerosol, fluffy catkins, and the bacterial community structure were investigated using culture-dependent and high-throughput sequencing methods. The results showed that the concentration of culturable bacteria was significantly higher (P=0.027) at the traffic site. The concentration of culturable bacteria at the traffic site was 2.7 times that of fungi, whereas the concentration of culturable fungi at the campus site was 1.4 times higher than that of bacteria. The peak concentrations of culturable bacteria and fungi appeared at 08:00 a.m. The size distribution of culturable bacteria showed a bimodal pattern, whereas that of culturable fungi showed a unimodal distribution. Soil and vegetation were the main sources of atmospheric microorganisms (85.9%), and Proteobacteria was the most abundant phylum in both fluffy catkins and PM2.5, accounting for 91.3% (traffic site) and 99.1% (campus site) of the fluffy catkins. Actinobacteria, Firmicutes, Bacteroidetes, Cyanobacteria, and Deinococcus-Thermus were the dominant phyla in PM2.5. Some genera were opportunistic pathogen bacteria in the fluffy catkins, such as Enterobacter and Pseudomonas, which can lead to infection and diarrhea risks. These results could provide fundamental data on potential health risks of spring-borne bioaerosols.

Influence of meteorological condition during rainstorm periods on the ambient concentrations of fungi in Bangkok, Thailand

Meteorological conditions change substantially during rainstorms, potentially affecting ambient concentrations of fungal spores. Exposure to ambient fungal spores during rainstorm periods may result in adverse health outcome such as thunderstorm asthma and allergic symptoms. This study investigated the ambient concentrations of culturable fungi during rainstorms period in Bangkok, Thailand. Using a single-stage impactor, air samples were collected between October and November 2017, when Thailand was struck by three major tropical cyclones: Typhoon Khanun, Typhoon Damrey, and Typhoon Kirogi. Fungal colonies were counted and identified according to their morphology. Meteorological data were obtained from the Thai Meteorological Department. Multiple regression analysis, performed to determine the associations between fungal concentrations and meteorological parameters, revealed a mean fungal concentration of 1,230 ± 1,136 CFU/m3 (n = 60). Fungal concentrations increased before the rainstorm arrival and decreased during the downpour rain. The fungal genera Cladosporium sp., Penicillium sp., and Aspergillus sp. were commonly observed but less than nonsporulating fungi, which accounted for more than 68% of all colonies. Fungal concentrations were positively associated with meteorological parameters, namely temperature, relative humidity, and maximum wind speed (R2 = 0.58, p < 0.05). Considerable changes in daily weather conditions during rainstorm periods strongly affected the fungal concentrations. Future studies should collect relevant hospital admission and more fungal monitoring data to determine the associations between fungal exposure during rainstorm periods and adverse outcomes.

Viable Airborne Fungi of Outdoor Environments of Yunusemre District, Manisa, Turkey

This research is on the viable air fungi was sampling during 12 months in the different points of Yunusemre. Fungal propagules were collected each month from eight isolation points. The concentrations of fungi were reported as cfu / m3 of air. Fungal identification was made according to their micro and macro morphological characters through the literature. As a result, the average concentration of culturable fungi is 412 cfu / m3 in Yunusemre air. 36 species in 9 genus were identified in this research. Penicillium is the most plenty genus that more than 33% of the all isolated fungi. Cladosporium was the preponderant fungal genus.

Assemblages of Culturable Airborne Fungi in a Typical Urban, Tourism-driven Center of Southeast China

ABSTRACT Assessing the prevalence of airborne fungi in a city or region is critical to diagnosing the ecology and effectively treating allergic manifestations induced by inhaling fungal allergens. The present study was conducted to evaluate the characteristics and variations of culturable airborne fungi at four selected sampling sites in Hangzhou in southeastern China. Results showed that the concentration of culturable fungi in the air ranged from < 12 colony forming units CFU m–3 to 8767 CFU m–3 with a mean of 848 CFU m–3. We identified a total of 352 fungal isolates from multiple sampling sites and across seasons, which were distributed among 21 genera and 85 species of fungi. Penicillium, Cladosporium, Alternaria, Aspergillus, and Trichoderma were the most predominant fungi, based on frequency and concentration, and the fungal composition differed both between sites and between seasons. Approximately 36.5% of the total number of isolated fungal species belonged to Penicillium, which also contributed the largest proportion of the total fungal concentration (about 29.6%). The most prevalent fungal species in Hangzhou were P. chrysogenum (7.7%), C. cladosporioides (6.3%), Alternaria alternata (5.6%), P. funiculosum (4.3%), and Aspergillus sydowii (4.0%). Moreover, significant variation existed between the sampling sites, with the highest fungal concentrations detected on Zhejiang Gongshang University Jiaogong Campus (ZJGSUJC) and Breeze-ruffled Lotus at Quyuan Garden (BLQG), followed by those on Yan’an Road Business Street (YRBS). The lowest concentrations (P < 0.05) were found on Tianmushan and Jiaogong Cross Road (TJCR). Furthermore, the concentrations at the four sites exhibited different seasonal patterns, with the lowest mean concentrations occurring during winter at all of the locations, whereas no difference was detected between summer, autumn, and spring. Our results provide a baseline for studying culturable airborne fungi in southeastern China, thus allowing the health risks from exposure to the atmosphere to be evaluated.

Seasonality in airborne bacterial, fungal, and (1→3)-β-D-glucan concentrations in two indoor laboratory animal rooms

AimsThe purpose of this study was to assess the temporal changes in the concentrations of bioaerosols in a laboratory mouse room (LMR) and laboratory rabbit room (LRR), and to determine...

Evaluation of aerosolization characteristics of biocontaminated particles from flood-damaged housing materials

The purpose of this study was to examine the aerosolization characteristics of biocontaminated particles, including particle release behavior and the concentrations of culturable fungi and (1→3)-β-D-glucan from four flood-affected floor and bedding materials. We applied an aerosolization process using multiple air jets, then measured the particles aerosolized from biocontaminated materials in real time using an optical particle counter, while simultaneously collecting particles in a BioSampler. The total count of particles released over 10min was highest from linoleum (25,503 particles/cm2), followed by rugs (1562 particles/cm2), carpets (508 particles/cm2), and pillows (24 particles/cm2). Linoleum, which has a hard surface, released particles the fastest (<6s) among the test materials. During fractional particle concentration analysis, the portion of submicron particles between 0.3 and 1.0μm was 66.1% (linoleum) – 77% (carpet) of the total particle concentration. Additionally, based on biological assays of the collected particles, the levels of culturable fungi and (1→3)-β-D-glucan in the four materials ranged from undetectable (linoleum; lower limit=0.2 CFU/cm2) to 0.83 CFU/cm2 (rug) and from 0.84 (carpet) to 3.26ng/cm2 (rug), respectively. We suggest that these results are helpful for further understanding of the aerosolization characteristics of biocontaminated particles from flood-affected materials, with benefits for the safe restoration of flood-damaged homes.

Fungal Bioaerosol Exposure and its Effects on the Health of Mushroom and Vegetable Farm Workers in Taiwan

ABSTRACTWorkers from specific occupational settings may be exposed to high fungal bioaerosol concentrations, causing detrimental health effects. Therefore, we conducted a study to evaluate the characteristics and health effects of fungal bioaerosols present on agricultural farms. By using IOM inhalable dust samplers, personal and area samples of airborne fungi were collected from five agricultural farms—two mushroom and three vegetable farms. A standardized questionnaire and spirometry were used to evaluate workers’ health. The Kruskal–Wallis test was used to examine the distributions of fungal and environmental factors among the different farms, and regression analyses were performed to evaluate the effects of personal bioaerosol exposure on workers’ health. In the personal samples, the geometric mean concentrations ranged from 4.3 × 103 to 3.0 × 104 CFU m–3 for total culturable fungi and from 4.2 × 103 to 1.2 × 105 spores m–3 for total fungal spores. The total fungal spore concentrations differed significantly among the personal samples (p = 0.026), but not among the area samples, from the five farms. The culturable fungal concentrations among the five farms did not differ significantly in the personal or area samples. Decreased lung functions of the workers were significantly associated with the concentrations of total fungi and several fungal taxa such as Ascospores, Fusarium, and Periconia. This study demonstrated that exposure to high fungal bioaerosol concentrations reduced the lung functions of the mushroom and vegetable farm workers. Superior ventilation and appropriate personal protection equipment are required to reduce occupational biohazards.

A survey of the aeromycota of Sydney and its correspondence with environmental conditions: grass as a component of urban forestry could be a major determinant

A comprehensive survey of airborne fungi has been lacking for the Sydney region. This study determined the diversity and abundance of outdoor airborne fungal concentrations in urban Sydney. Monthly air samples were taken from 11 sites in central Sydney, and culturable fungi identified and quantified. The genus Cladosporium was the most frequently isolated fungal genus, with a frequency of 78 % and a mean density of 335 CFU m -3 . The next most fre- quently encountered genus wasAlternaria,occurringin 53 % of samples with a mean of 124 CFU m -3 .O ther frequently identified fungi, in decreasing occurrence, were as follows: Penicillium, Fusarium, Epicoccum, Phoma, Acremonium and Aureobasidium .A dditional- ly, seasonal and spatial trends of airborne fungi were assessed, with increases in total culturable fungal concentrations experienced in the summer months. The correspondence between a range of key environ- mental variables and the phenology of airborne fungal propagules was also examined, with temperature, wind speed and proximal greenspace having the largest influenceonfungalpropaguledensity.Ifthegreenspace

Removal of Viable Airborne Fungi from Indoor Environments by Benzalkonium Chloride-Based Aerosol Disinfectants

ABSTRACTFungi are ubiquitous in indoor environments, and some taxa can cause clinical symptoms in humans. Thus, from the viewpoint of public health, methods to reduce indoor airborne fungi are needed. The goal of this study was to examine the efficacies of benzalkonium chloride (BAC)–based aerosol disinfectants to remove airborne viable fungi from indoor environments. The laboratory- and field-based experiments were conducted to compare airborne culturable fungal concentrations before and after the disinfectant aerosol applications. The laboratory-based experiments showed the greater efficacies by the BAC-based disinfectant aerosol than by pure-water control aerosol (p <.05, t-test). In the field study using the BAC-based disinfectant aerosols, on average a 58% reduction of total airborne culturable fungal concentrations were observed. Additionally, the significant reduction was found for a group of airborne yeasts or yeast-like organisms (p <.05, Wilcoxon signed rank test). The BAC-based aerosol disinfectants are effective when used to reduce the numbers of airborne culturable fungi, in particular yeasts or yeast-like organisms, from indoor environments.

Comparison of background levels of culturable fungal spore concentrations in indoor and outdoor air in southeastern Austria

Background concentrations of airborne fungi are indispensable criteria for an assessment of fungal concentrations indoors and in the ambient air. The goal of this study was to define the natural background values of culturable fungal spore concentrations as reference values for the assessment of moldy buildings. The concentrations of culturable fungi were determined outdoors as well as indoors in 185 dwellings without visible mold, obvious moisture problems or musty odor. Samples were collected using the MAS-100® microbiological air sampler.The study shows a characteristic seasonal influence on the background levels of Cladosporium, Penicillium and Aspergillus. Cladosporium sp. had a strong outdoor presence, whereas Aspergillus sp. and Penicillium sp. were typical indoor fungi. For the region of Styria, the median outdoor concentrations are between 100 and 940 cfu/m³ for culturable xerophilic fungi in the course of the year. Indoors, median background levels are between 180 and 420 cfu/m³ for xerophilic fungi. The I/O ratios of the airborne fungal spore concentrations were between 0.2 and 2.0. For the assessment of indoor and outdoor air samples the dominant genera Cladosporium, Penicillium and Aspergillus should receive special consideration.

Impacts of Asian dust events on atmospheric fungal communities

The composition of atmospheric fungi in Seoul during Asian dust events were assessed by culturing and by molecular methods such as mold specific quantitative PCR (MSQPCR) and internal transcribed spacer cloning (ITS cloning). Culturable fungal concentrations in the air were monitored from May 2008 to July 2011 and 3 pairs of ITS clone libraries, one during Asian dust (AD) day and the other during the adjacent non Asian dust (NAD) day for each pair, were constructed after direct DNA extraction from total suspended particles (TSP) samples. In addition, six aeroallergenic fungi in the atmosphere were also assessed by MSQPCR from October, 2009 to November, 2011. The levels of the airborne culturable fungal concentrations during AD days was significantly higher than that of NAD days (P < 0.005). In addition, the correlation of culturable fungal concentrations with particulate matters equal to or less than 10 μm in aerodynamic diameter (PM10) concentrations was observed to be high (0.775) for the AD days while correlation coefficients of PM10 as well as other particulate parameters with airborne fungal concentrations were significantly negative for the NAD days during intensive monitoring periods (May to June, 2008). It was found that during AD days several airborne allergenic fungal levels measured with MSQPCR increased up to 5–12 times depending on the species. Comparison of AD vs. NAD clones showed significant differences (P < 0.05) in all three cases using libshuff. In addition, high proportions of uncultured soil fungus isolated from semi-arid regions were observed only in AD clone libraries. Thus, it was concluded that AD impacts not only airborne fungal concentrations but also fungal communities.

Spectrum and Concentration of Culturable Fungi in House Dust from Flats in Warsaw, Poland

Samples of house dust from 18 flats in Warsaw (Poland) were collected from five environments: floor, shelves with books, kitchen, bathroom, and bed. Penicillium, Aspergillus, Cladosporium and Alternaria were the most common genera identified in house dust samples. The highest culturable fungal concentrations were recorded in dust from shelves (median value 8.2 × 10 4 CFU/g of dust), and the least one from beds (median value 8.0 × 10 3 CFU/g of dust). Differences in CFUs between environments were statistically significant for Penicillium, Aspergillus and Alternaria. Concentrations of Penicillium and Aspergillus were significantly higher in autumn than in spring, whereas that of Cladosporium was significantly lower in autumn than in spring. The efficiency of ventilation in the bathroom had a significant effect on Cladosporium counts. Certain relationships between the concentrations of culturable fungi and some customs of the occupants are discussed.

Seasonal and Spatial Variations of Bioaerosols in Indoor Urban Environments, Ankara, Turkey

Seasonal and spatial variations of both levels and characteristics of airborne bacteria and fungi in various types of non-complaint indoor environments and their outdoors were investigated. Bioaerosol samples were collected by the single-stage Andersen sampler during the winter and summer seasons in Ankara, Turkey. Indoor and outdoor temperature, relative humidity (RH) and CO2 concentrations were also monitored online during the sampling. Bacteria levels in apartments were found to be considerably elevated when people were present. Significant relationships between bioaerosol levels and RH and CO2 concentrations ( p&lt;0.05) were found. Bacteria levels exhibited a seasonal variation, while fungi levels did not, probably due to lower fungi concentrations occurrence as a result of lower RH values (median: 30%). Measured low levels of fungi in this study may be due to geographical conditions, climatic factors, and other environmental conditions. The indoor to outdoor (I/O) ratio for bacteria levels were found to be significantly higher than 1.0, while indoor and outdoor fungi levels were similar. Winter to summer (W/S) ratios in the sampling site groups varied on a large scale for both culturable fungi concentrations (0.24–19.59) and total bacteria count (0.16–6.59). The most prominent bacteria were Micrococcus spp., Staphylococcus spp. and Bacillus spp., while the most predominant fungi were Penicillium spp., Aspergillus spp. and Cladosporium spp.

Changes in profiles of airborne fungi in flooded homes in southern Taiwan after Typhoon Morakot

In August 2009, the historic Typhoon Morakot brought extreme rainfall and resulted in flooding which spread throughout southern Taiwan. This study compared the difference between fungal concentrations before and after the disaster in selected homes of the Tainan metropolitan area, which were hit hardest by the catastrophe. A group of 83 households available from a prior cohort established with random sampling out of a regional population in southern Taiwan was contacted successfully by telephone. Twenty-five of these reported to have suffered from floods of various degrees at this time. Around 2 weeks after the event, at which time most of the remedial process had been completed by self-efforts and public health endeavours, 14 of these 25 (56%) agreed to participate in measurements of the airborne microbial concentrations. The averages (standard deviation) of the total culturable fungal concentrations in children's bedrooms and flooded rooms were 18,181 (25,854) colony-forming units per cubic metre (CFU/m 3) and 13,440 (11,033) CFU/m 3, respectively. The airborne fungal spore levels in the 2 above-mentioned indoor sites were 221,536 (169,640) spores/m 3 and 201,582 (137,091) spores/m 3, respectively. The average indoor/outdoor ratios in the children's bedrooms were 4.2 for culturable fungi and 1.4 for fungal spores. These values were higher than the respective values measured in the same homes during the previous year: 1.1 and 0.6. In terms of the specific fungal profile, the percentages of Aspergillus spp. increased significantly in both the indoor and outdoor environments after the event. To this date, this study is among the limited research that has been conducted to quantitatively demonstrate that fungal manifestation is likely to persist in flooded homes even after seemingly robust remedial measures have been put into place. Studies to examine the potential health implications and effectiveness of better remedial technology remain much needed.

Seasonal Fine and Coarse Culturable Fungal Constituents and Concentrations from Indoor and Outdoor Air Samples Taken from an Arid Environment

This study was undertaken to determine the normal indoor and outdoor airborne culturable fungal constituents and concentrations of an arid environment. Air samples were taken with two-stage, ambient, culturable sampler systems and analyzed for nine specific fungal genera from 50 homes as a repeated measure during each season of the year. These homes had no previous histories of indoor air quality issues. This study detected seasonal differences for the arid environment between different culturable fungal concentrations across the two size ranges. The highest concentrations were during fall, in the outdoor fine-size range. The lowest concentrations were the indoor coarse concentrations in the spring. From this study it can be concluded that Cladosporium spp. had the highest concentrations during fall in an arid environment. The overall findings suggest that Cladosporium had concentrations greater than the other genera evaluated, specifically, the fall outdoor fine concentrations. Seasonality was found to be a key factor in determining the variability of fungal constituents and concentrations within the arid indoor and outdoor environments. The fine-size range was 12 times and 6 times greater than the coarse-size range for indoor and outdoor samples, respectively, which accounted for the majority of fungal organisms. In addition, the results from this study in an arid climate differ from those conducted in a moister climate.

Longitudinal Evaluation of Allergen and Culturable Fungal Concentrations in Inner-City Households

To characterize seasonal variation of three allergens (dust mite, cat, and cockroach) and total culturable fungi and to explore whether residential characteristics were associated with the concentrations of these agents, floor dust was collected from 47 inner-city homes in Minneapolis, Minnesota, over a 1-year period. A longitudinal analysis of allergen and fungal concentrations was carried out using mixed-effect models. Overall, relative humidity was a better predictor of allergen concentrations over time than indoor temperature. Seasonal variation of cat and cockroach allergens was negligible compared with the variability associated with residential characteristics such as race/ethnicity, family income, and the presence of cats. Fungal concentrations showed significant seasonal variation that outweighed the variability associated with residential characteristics. Less than 30% of the dust mite allergen and cockroach allergens concentrations were above limits of detection. Observed cockroach allergen concentrations were higher in Spanish- and Somali-speaking households than in English-speaking households, while English-speaking households had significantly higher cat allergen concentrations compared with the other language groups. The ratios of within-home to between-home variance for total culturable fungi, dust mite, cockroach, and cat allergen concentrations were 2.54, 1.91, 0.55, and 0.24, respectively. This ratio is used to predict the number of repeated measurements of each allergen required to robustly estimate long-term exposure estimates such that exposure misclassification bias is kept within acceptable limits. It is not clear whether repeated measurements of dust mite and cockroach allergens are required for long-term average exposure because of the large fraction of nondetects. It is concluded that a single measurement of cat allergen is a reasonable surrogate for long-term average exposure, since repeated measurements over time were highly correlated. Total culturable fungi will require greater than nine repeated measurements for robust assessment of long-term exposures because of low correlations in fungal measures over time.

Biodiversity and concentrations of airborne fungi in large US office buildings from the BASE study

The Building Assessment Survey and Evaluation (BASE) study measured baseline concentrations of airborne fungi in 100 representative US office buildings in 1994–1998. Multiple samples for different sampling durations, sites, and times of the day were aggregated into building-wide indoor and outdoor average concentrations. Fungal concentrations were compared between locations (indoor vs. outdoor), sampling and analytical methods (culture vs. microscopy), and season (summer vs. winter). The arithmetic means (standard deviations) of the indoor/outdoor concentrations of culturable fungi and fungal spores were 100/680 (230/840) CFU m - 3 and 270/6540 (1190/6780) spore m - 3 , respectively. Although fewer groups were observed indoors than outdoors, at lower average concentrations (except in two buildings), site-specific and building-wide indoor measurements had higher coefficients of variation. More groups were seen in summer, and aggregated concentrations tended to be higher than in winter except for culturable Aureobasidium spp. and Botrytis spp. outdoors and non-sporulating fungi in both locations. Rankings of the predominant fungi identified by both methods were similar, but overall indoor and outdoor spore concentrations were approximately 3 and 10 times higher, respectively, than concentrations of culturable fungi. In the 44 buildings with both measurements, the indoor and outdoor total culturable fungi to fungal spore ratios (total C / S ratios) were 1.27 and 0.25, with opposite seasonal patterns. The indoor C / S ratio was higher in summer than in winter (1.47 vs. 0.86; N = 29 and 15, respectively), but the outdoor ratio was lower in summer (0.19 vs. 0.36, respectively). Comparison of the number of different fungal groups and individual occurrence in buildings and samples indicated that the outdoor environment and summer season were more diverse, but the proportional contributions of the groups were very similar suggesting that the indoor and outdoor environments were related as were summer and winter seasons for each location. The extreme (e.g., 90th percentile) indoor concentrations ( 200 CFU m - 3 and 210 spore m - 3 ) may provide reference values for non-complaint US office environments.

Evaluating Fungal Populations by Genera/Species on Wide Body Commercial Passenger Aircraft and in Airport Terminals

Given the potential health effects of fungi and the amount of time aircrew and passengers spend inside aircraft, it is important to study fungal populations in the aircraft environment. Research objectives included documenting the genera/species of airborne culturable fungal concentrations and total spore concentrations on a twin-aisle wide body commercial passenger aircraft. Twelve flights between 4.5 and 6.5 h in duration on Boeing 767 (B-767) aircraft were evaluated. Two air cooling packs and 50% recirculation rate (i.e. 50:50 mix of outside air and filtered inside air) were utilized during flight operations. Passenger occupancy rates varied from 67 to 100%. N-6 impactors and total spore traps were used to collect sequential, triplicate air samples in the front and rear of coach class during six sampling intervals throughout each flight: boarding, mid-climb, early cruise, mid-cruise, late cruise and deplaning. Comparison air samples were also collected inside and outside the airport terminals at the origin and destination cities resulting in a total of 522 culturable and 517 total spore samples. A total of 45 surface wipe samples were collected using swabs onboard the aircraft and inside the airport terminals. A variety of taxa were observed in the culturable and total spore samples. A frequency analysis of the fungal data indicated that Cladosporium, Aspergillus and Penicillium were predominant genera in the culturable samples whereas Cladosporium, Basidiospores and Penicillium/Aspergillus were predominant in the total spore samples. Fungal populations observed inside the aircraft were comprised of similar genera, detected significantly less frequently and with lower mean concentrations than those observed in typical office buildings. Although sources internal to the aircraft could not be ruled out, our data demonstrate the importance of passenger activity as the source of the fungi observed on aircraft. Isolated fungal peak events occurred occasionally when concentrations of a particular genus or species rose sharply inside the cabin for a limited period. Overall, our research demonstrates that on the sampled flights the B-767 filtration system operated efficiently to remove fungal spores when two air cooling packs and 50% recirculation rate were utilized during flight operations.

Evaluation of Culturable Particle Load on HVAC Filters Before and After Remediation: A Pilot Study

This pilot research was performed to evaluate a quantitative method for culturing particles on HVAC filters. The reasons were to compare relative concentrations of culturable fungi found in two separate rooms of a six-floor building and to re-evaluate culturable fungi in the same building after remediation efforts. The evaluated quantification method involved shaking samples of filter materials in sterile saline followed by plating out. The pilot study consisted of two phases. Firstly, a case study comparison of two HVAC filters from a building with a history of indoor air quality concerns in the space served by one of the filters. The second, following remediation efforts in the same building. This involved the quantification of culturable fungal particles on each of ten filters serving ten separate areas of the building. Statistical analysis of the phase I results indicated a significantly greater number of viable particles on the complaint filter than on the non-complaint filter following culture and quantification on either malt extract agar (p=0.02) or potato dextrose agar (p=0.03). Phase II results suggested a factor of four decrease in culturable fungal load following remediation. This limited study was performed for preliminary assessment of the use of a filter quantification method to estimate relative airborne fungal load. The results suggest that more work is merited but limitations in the scope of the research and the statistical power of the analysis mean further conclusions regarding method efficacy cannot be drawn.