Microbiological indoor air quality in healthy buildings

There is a growing interest in indoor air quality for a better quality environment both at home and at work because many people spend at least 80% of their time indoors. The aim of our study was to evaluate the indoor concentration of airborne bacteria and fungi in a University auditorium, in an office of public buildings and in an apartment in the presence and in absence of building's occupants, building materials and furnishings. The concentrations of airborne bacteria and fungi were determined using a Surface Air System (SAS). In presence of people and furnishings the average air concentrations of bacteria (University auditorium: 925-1225 CFU m(-3); office: 493 CFU m(-3); apartment: 92-182 CFU m(-3)) were higher than in absence (respectively: 190-315 CFU m(-3); 126 CFU m(-3); 66-80 CFU m(-3)). The average air concentrations fungal were higher in presence of people and furnishings (University auditorium: 1256-1769 CFU m(-3); office: 858 CFU m(-3); apartment: 147-297 CFU m(-3)) than in absence (respectively: 301-431 CFU m(-3); 224 CFU m(-3); 102-132 CFU m(-3)). The obtained data can be considered as a step to identify acceptable levels for bioaerosols in common indoor environments.     

Exposure of workers to airborne microorganisms in open-air swine houses

This study quantified the levels of airborne microorganisms in six swine farms with more than 10,000 pigs in subtropical Taiwan. We evaluated breeding, growing, and finishing stalls, which were primarily open-air buildings, as well as partially enclosed farrowing and nursery piggeries. Airborne culturable bacteria, gram-negative bacteria, and fungi were placed on appropriate media by using an all-glass impinger or single-stage Andersen microbial sampler. Results showed that mean concentrations of culturable bacteria and gram-negative bacteria were 3.3 x 10(5) and 143.7 CFU/m(3), respectively. The concentration of airborne culturable fungi was about 10(3) CFU/m(3), with Cladosporium the predominant genus. The highest airborne levels of culturable bacteria and gram-negative bacteria were identified in the finishing units. The air of the nursery stalls was the least contaminated with culturable and gram-negative bacteria. Irregular and infrequent cleaning, high pig density, no separation of wastes from pen floors, and accumulation of water as a result of the processes for cleaning and reducing pig temperature possibly compromise the benefits of the open characteristic of the finishing units with respect to airborne bacterial concentration.     

Atmospheric culturable bacteria associated with meteorological conditions at a summer-time site in the mid-Willamette Valley,Oregon

A set of simultaneously collected quantitative measurements of 12 meteorological and 6 culturable atmospheric bacterial (CAB) variables was made over a grass seed field during several early, mid, and late summer days. The observation site was located between the Cascade and Coastal Mountain Ranges near Corvallis in the Willamette Valley, Oregon. Principal component analysis identified those meteorological variables that had the highest loadings in six eigenvectors that account for 95.9% of variation in the data factors, i.e., temperature @ 6.3 m above ground level (AGL), wind velocity @ 10.0 m AGL, wind velocity difference @ 1.7–10.0 m, barometric pressure, wind direction standard deviation, and wind direction. When these variables were used in a cluster analysis, they formed three statistically distinct meteorological variable clusters with means at ca. “midnight”, ca. “midday”, and ca. “evening.” The highest mean density of CAB (i.e., 153.4 ± 162.5 CFU/m³) was associated with the “midday” meteorological Cluster-1 that had warm, dry “gentle breezes” from the southeast, in the relatively bacteria loaded Willamette Valley air. The lowest mean density of CAB (i.e., 35.5 ± 24.1 CFU/m³) was associated with meteorological Cluster-3 in the late afternoon and “evening” occurring during the hottest and driest part of the day with “fresh breezes” coming from the north northwest in air off the Pacific Ocean. Finally, the last cluster, Cluster-2 occurred about midnight and had an intermediate density of CAB (74.2 ± 76.2 CFU/m³) in “light air” coming from the northwest, perhaps off the Pacific Ocean. The CAB associated with each of the three meteorological clusters was only partially statistically distinct. Partially because the CAB in both the Pacific Ocean derived air masses of the “evening” Cluster-3 and “midnight” Cluster-2 were not statically separable, though both were statistically separable from the midday, Willamette Valley derived Cluster-1. Further indicating their common source, both Pacific Ocean derived air masses had very similar percentages of pigmented bacteria, which were dissimilar to the pigmented bacterial population density in the Willamette Valley air masses. In short, it is speculated that “midnight” atmosphere may simply contain the settling concentrated residual bacterial particles in the abated fresh Pacific Ocean breezes after sundown. It is clearly shown that with the methods employed, it is possible to associate the uniqueness of the quantity, and to a lesser extent the quality, of the CAB population with the atmospheric conditions reported herein. From this project comes speculation that the strategies relating the quasi-conservative bacterial populations associated with distinct but nonconservative air mass properties can help to better understand more of the bacterial dynamics found in such situations. And to a further extent, molecular biological methods could be applied to identify bacterial taxa in specific air masses.     

Site-related and seasonal variation of bioaerosol emission in an indoor wastewater treatment station: level,characteristics of particle size,and microbial structure

The emission of the airborne bacteria and fungi from an indoor wastewater treatment station adopting an integrated oxidation ditch with a vertical circle was investigated. Microbial samples were collected by the six-stage viable Andersen cascade impactor, and the samples were collected in triplicate in each sampling site per season. Culture-based method was applied to determine the concentrations of the airborne bacteria and fungi, while the cloning/sequencing method was used to characterize the genetic structure and community diversity of airborne bacteria. The highest concentrations of airborne bacteria (4155 ± 550 CFU/m³) and fungi (883 ± 150 CFU/m³) were obtained in June (summer). The lowest concentration of bacteria (1458 ± 434 CFU/m³) was determined in January (winter), and the lowest concentration of fungi (169 ± 40 CFU/m³) was found in March (spring), respectively. The particle size distribution analysis showed that most culturable bacteria obtained in all the sampling sites were in the particle size range of 1.1–4.7 µm. Most culturable fungi had particle sizes in the range 1.1–3.3 µm. Microbial population analysis showed that Bacillus sp., Acinetobacter sp., and Lysinibacillus were the main groups obtained in S1. Enterobacter was the dominant group in sampling site S2. Both the concentrations and particle size distribution of the bioaerosols in the enclosed space presented a seasonal and site-related variation. Concentration and richness of microorganisms in bioaerosols in June were higher than in September and January. The particle size distribution varied between the sampling sites, and proportion of large particles was higher in S2 than in S1 because of the settlement of large particles. Pathogenic species, such as Acinetobacter lwoffii, Staphylococcus saprophyticus, and Enterobacter sp., were isolated from the bioaerosols, which could pose serious latent danger to sewage workers’ health.     

The aerobiological results from the 1994 cruise of the Urania (cnr) on the Adriatic. I. Pollen and spore counts on the Mediterranean sea as compared to mainland Italia

In July 1994, we were able to collect airborne fungal spores and pollen grains over the Adriatic Sea from the upper deck of the Oceanographic Ship Urania (CNR). The biological particles were collected using a modified Lanzoni VPPS 1000 sampler (operating at a flux of 10 LPM), on glycerine-gelatine coated microscopic slides. Not only were the airborne concentrations of different organisms estimated, their viability was also tested with a 1% TTC solution. Particles were collected for 60 min (i.e. a volume of 600 liters of air sampled) at every 2 h from 0600–2100 h. Up to 689 pollen grains/m³ and an impressive 48 990 spores/m³ were collected daily. Forty-two fungal taxa were identified and the most abundant spores collected were Cladosporium (82.6%), Smuts (4.8%), Ascospores (2.8%), Basidiospores (2.1%) andAlternaria (1.7%). 20 pollen taxa were identified, and the dominant pollen were Urticaceae (57.9%), Graminaceae (20.7%), Fagaceae (2.4%), Plantaginaceae (1.4%), Pinaceae (1.3%) and Eucalyptus (1.1%). The most abundant captures were done at 0800 and 1000 h (17.8 and 16.7% respectively) and at 1400 and 1600 h (13.2 and 13.8% respectively). Pollen viability per species ranged from 0 to 100%, but for the most abundant taxa, it ranged from 3.8 to 75%, and averaged 27.7%. Maximum viability was found at 0800 and 1200 h. Pollen concentrations were of the same order of magnitude as the ones found on the mainland (Brindisi, Chieti, Matera). However, its specificity was evident. Future work should therefore look more at the pollen transport process which should account for this different assemblage of pollen.     

The aerobiological results from the 1994 cruise of the Urania (cnr) on the Adriatic. I. Pollen and spore counts on the Mediterranean sea as compared to mainland Italia

In July 1994, we were able to collect airborne fungal spores and pollen grains over the Adriatic Sea from the upper deck of the Oceanographic Ship Urania (CNR). The biological particles were collected using a modified Lanzoni VPPS 1000 sampler (operating at a flux of 10 LPM), on glycerine-gelatine coated microscopic slides. Not only were the airborne concentrations of different organisms estimated, their viability was also tested with a 1% TTC solution. Particles were collected for 60 min (i.e. a volume of 600 liters of air sampled) at every 2 h from 0600–2100 h. Up to 689 pollen grains/m³ and an impressive 48 990 spores/m³ were collected daily. Forty-two fungal taxa were identified and the most abundant spores collected were Cladosporium (82.6%), Smuts (4.8%), Ascospores (2.8%), Basidiospores (2.1%) andAlternaria (1.7%). 20 pollen taxa were identified, and the dominant pollen were Urticaceae (57.9%), Graminaceae (20.7%), Fagaceae (2.4%), Plantaginaceae (1.4%), Pinaceae (1.3%) and Eucalyptus (1.1%). The most abundant captures were done at 0800 and 1000 h (17.8 and 16.7% respectively) and at 1400 and 1600 h (13.2 and 13.8% respectively). Pollen viability per species ranged from 0 to 100%, but for the most abundant taxa, it ranged from 3.8 to 75%, and averaged 27.7%. Maximum viability was found at 0800 and 1200 h. Pollen concentrations were of the same order of magnitude as the ones found on the mainland (Brindisi, Chieti, Matera). However, its specificity was evident. Future work should therefore look more at the pollen transport process which should account for this different assemblage of pollen.     

Human plasma DSIP decreases at the initiation of sleep at different circadian times

Nocturnal plasma delta sleep-inducing peptide-like immunoreactivity (DSIP-LI) was determined serially in seven healthy male subjects. Time courses during nocturnal sleep (2300-0800 h), nocturnal sleep deprivation (2300-0500 h), and morning recovery sleep (0500–0800 h) after sleep deprivation were compared. A significant decrease in plasma DSIP-LI was found at the transition from wakefulness to sleep in both evening sleep (2300 h) and morning recovery sleep (0500 h). Time courses were accompanied by physiological changes in sleep electroencephalographic slow-wave activity, and in plasma concentrations of cortisol and human growth hormone. No sleep stage specificity was found. It is concluded that DSIP is influenced by the initiation of sleep.     

Culturable Airborne Bacteria in Outdoor Environments in Beijing,China

Airborne bacteria are important biological components of bioaerosol and play an important role in ecosystem. Bacteria at a high concentration in the atmosphere can result in biological air pollution and all kinds of diseases. In this study, a systematical survey on the culturable airborne bacteria was carried out for 1 year at three sites in Beijing urban area. Results showed that concentrations of culturable bacteria ranged from 71 colony forming units (CFU)/m³ to 22,100 CFU/m³, and the mean was 2,217 CFU/m³. Bacterial concentrations at the human activity-enriched site (RCEES) and the highly trafficked site (XZM) were virtually the same point. They were significantly higher than those at the greener site (BBG). Significant variation in bacterial concentrations in different seasons was observed at RCEES and XZM with higher concentrations in summer and autumn. In a single day, significantly lower concentrations were detected at 13:00 hours through all sampling sites. In this study, 165 species in 47 genera of culturable bacteria were identified. Micrococcus was one of the most dominant bacterial groups and contributed to approximately 20∼30% of the total bacterial concentration, followed by Staphylococcus, Bacillus, Corynebacterium, and Pseudomonas. The bacterial species with a high concentration percentage included Micrococcus luteus and Micrococcus roseus.     

Sea–land breeze in a coastal city and its effect on pollen transport

This paper presents a statistical study of the sea-land breeze in Mar del Plata (Argentina) to characterize the periods of the year when the breeze affects pollen transport, particularly the dispersion of airborne Poaceae pollen between urban and rural areas. In order to analyse the sea breeze circulation, hourly data from coastal, urban and rural meteorological stations were used. The effect of the sea breeze on the particulate matter was analysed from syncronic hourly airborne pollen records from an urban and a rural area. A sea-land breeze appeared between spring and early autumn in the hours of greatest diurnal warming. Results showed that the surface wind direction most probably associated with this phenomenon is NE and E, the time of occurrence shifting to new directions following the counterclockwise rotation, according to theoretical models for the Southern Hemisphere. Poaceae emission takes place in the morning, during the hours of maximum insolation. However, after the occurrence of the breeze, a rise in pollen concentration between 2000 hours and 0200 hours is detected because of pollen reentrainment brought about by air recirculation. The results showed that breeze transport brings a regional component to pollen assemblage.     

Intestinal bacterial communities that produce active estrogen-like compounds enterodiol and enterolactone in humans

Lignans are dietary diphenolic compounds which require activation by intestinal bacteria to exert possible beneficial health effects. The intestinal ecosystem plays a crucial role in lignan metabolism, but the organisms involved are poorly described. To characterize the bacterial communities responsible for secoisolariciresinol (SECO) activation, i.e., the communities that produce the enterolignans enterodiol (ED) and enterolactone (EL), a study with 24 human subjects was undertaken. SECO activation was detected in all tested fecal samples. The intestinal bacteria involved in ED production were part of the dominant microbiota (6 x 10(8) CFU g(-1)), as revealed by most-probable-number enumerations. Conversely, organisms that catalyzed the formation of EL occurred at a mean concentration of approximately 3 x 10(5) CFU g(-1). Women tended to have higher concentrations of both ED- and EL-producing organisms than men. Significantly larger amounts of EL were produced by fecal dilutions from individuals with moderate to high concentrations of EL-producing bacteria. Two organisms able to demethylate and dehydroxylate SECO were isolated from human feces. Based on 16S rRNA gene sequence analyses, they were named Peptostreptococcus productus SECO-Mt75m3 and Eggerthella lenta SECO-Mt75m2. A new 16S rRNA-targeted oligonucleotide probe specific for P. productus and related species was designed and further used in fluorescent in situ hybridization experiments, along with five additional group-specific probes. Significantly higher proportions of P. productus and related species (P = 0.012), as well as bacteria belonging to the Atopobium group (P = 0.035), were typical of individuals with moderate to high concentrations of EL-producing communities.     

Diurnal variation in airborne pollen concentrations of the selected taxa in Zagreb, Croatia

The number of individuals allergic to plant pollen has recently been on a constant increase. The knowledge of diurnal distribution and abundance of allergenic pollen types, their patterns and response to source position and weather is useful to correlate hay fever symptoms with the presence of allergenic pollen in the atmosphere. The aim of this study was to determine diurnal distribution of total airborne pollen, pollen of particular allergenic taxa, possible variation in diurnal pollen distribution at measuring sites placed at different heights, and effect of some meteorological parameters on airborne pollen concentrations. A 7-day Hirst-type volumetric pollen trap was used for pollen sampling. Qualitative and quantitative pollen analysis was performed under a light microscope (magnification x400). Total pollen of all plant taxa (Ambrosia sp., Betula sp., Cupressaceae, Urticaceae, Poaceae, Quercus sp., Fraxinus sp., Alnus sp., Corylus sp., Populus sp., Pinus sp., Picea sp.) observed showed a regular diurnal distribution at both sampling sites in both study years, with a rise in the pollen concentration recorded after 4.00 a.m. and 6.00 a.m., respectively. The peak pollen concentration occurred between 12.00 a.m. and 4.00 p.m., and the lowest diurnal pollen concentrations were recorded overnight. About 50% of the 24-h pollen concentration were released to the atmosphere between 10.00 a.m. and 4.00 p.m. The timing and size of diurnal peaks were closely related to high temperature, low humidity and south-west maximum wind direction.     

Prokaryotic and Eukaryotic Airborne Microorganisms as Tracers of Microclimatic Changes in the Underground (Postojna Cave, Slovenia)

Bioaerosols in cave air can serve as natural tracers and, together with physical parameters, give a detailed view of conditions in the cave atmosphere and responses to climatic changes. Airborne microbes in the Postojna Cave system indicated very dynamic atmospheric conditions, especially in the transitory seasonal periods between winter and summer. Physical parameters of cave atmosphere explained the highest variance in structure of microbial community in the winter and in the summer. The airborne microbial community is composed of different microbial groups with generally low abundances. At sites with elevated organic input, occasional high concentrations of bacteria and fungi can be expected of up to 1,000?colony-forming units/m(3) per individual group. The most abundant group of airborne amoebozoans were the mycetozoans. Along with movements of air masses, airborne algae also travel deep underground. In a cave passage with elevated radon concentration (up to 60?kBq/m(3)) airborne biota were less abundant; however, the concentration of DNA in the air was comparable to that in other parts of the cave. Due to seasonal natural air inflow, high concentrations of biological and inanimate particles are introduced underground. Sedimentation of airborne allochthonous material might represent an important and continuous source of organic material for cave fauna.     

Three-year investigation of the natural airborne bacterial flora at four localities in sweden.

The concentration of airborne bacteria was recorded during a period of 3 years at four localities: (i) in an agricultural district with an average of 99 (range, 2 to 3,400) bacteria per m3; (ii) in a coastal area with an average of 63 (range, 0 to 560) bacteria per m3; (iii) in a city park with an average of 763 (range, 100 to 2,500) bacteria per m3; and (iv) in a city street with an average of 850 (range, 100 to 4,000) bacteria per m3. At all four localities the bacterial concentrations varied within broad limits, but an annual periodicity with high average counts found during summer and autumn could be seen. The influence of certain meteorological factors on the number of airborne bacteria is also reported. Rain or high relative humidity caused a decrease in the bacterial counts, while high temperature or high wind velocities increased the counts. The particle size distribution for the four localities showed that about 50% of the particles carrying bacteria were larger than 8 micrometer.     

Exposure of Workers to Airborne Microorganisms in Open-Air Swine Houses

This study quantified the levels of airborne microorganisms in six swine farms with more than 10,000 pigs in subtropical Taiwan. We evaluated breeding, growing, and finishing stalls, which were primarily open-air buildings, as well as partially enclosed farrowing and nursery piggeries. Airborne culturable bacteria, gram-negative bacteria, and fungi were placed on appropriate media by using an all-glass impinger or single-stage Andersen microbial sampler. Results showed that mean concentrations of culturable bacteria and gram-negative bacteria were 3.3 × 10⁵ and 143.7 CFU/m³, respectively. The concentration of airborne culturable fungi was about 10³ CFU/m³, with Cladosporium the predominant genus. The highest airborne levels of culturable bacteria and gram-negative bacteria were identified in the finishing units. The air of the nursery stalls was the least contaminated with culturable and gram-negative bacteria. Irregular and infrequent cleaning, high pig density, no separation of wastes from pen floors, and accumulation of water as a result of the processes for cleaning and reducing pig temperature possibly compromise the benefits of the open characteristic of the finishing units with respect to airborne bacterial concentration.     

Are modifications of melatonin circadian rhythm in the middle years of life related to habitual patterns of light exposure?

The mechanisms underlying age-related changes in the signal from the biological clock have yet to be determined. The authors sought to determine if the phase advance of circadian melatonin rhythm during the middle years of life is related to different patterns of habitual light exposure. Forty-one healthy subjects between the ages of 22 and 58 y were studied. Habitual light exposure was measured by a wrist monitor for 7 days. Participants underwent a 25-h constant routine. They provided saliva samples every 30 min, and melatonin concentration was determined by radioimmunoassay to assess salivary dim light melatonin onset (S-DLMO(1.3)). Aging was associated with earlier S-DLMO(1.3). Increasing age was not related to the time spent at different light intensities. However, it was associated with lower percentage of light exposure during the night (between 0200-0400, 0600-0700, and 2300-2400 h) and with higher percentage of light exposure in the morning (between 0800-1100 h). Earlier S-DLMO(1.3) was associated with lower percentage of light exposure early on in the night (between 2200-0000, 0000-0100, and 0200-0300 h) as well as in the afternoon (between 1500-1600 h) and with higher percentage of light exposure in the morning (between 0800-1100 h). When the effects of age were controlled, there was no significant relationship between S-DLMO(1.3) and percentages of light exposure. Yet increasing age was associated with earlier S-DLMO(1.3) regardless of light exposure patterns. Earlier habitual wake time explained the earlier light exposure patterns of older subjects. Both habitual wake time and age contributed to the prediction of S-DLMO(1.3). The results suggest a phase advance of circadian rhythms in the middle years of life. Whereas a clear change in habitual light exposure patterns was associated with aging and with shifts in S-DLMO(1.3), it did not explain entirely the age-related advance of melatonin circadian phase.     

麦积山石窟赋存环境中空气细菌的时空分布特征

【目的】空气微生物沉降及污染与文化遗产的微生物退化密切相关,本文对世界文化遗产地麦积山石窟赋存环境空气中细菌浓度和群落结构的季节性变化特征进行了系统研究,为石窟环境监测预警和文物预防性保护提供依据。【方法】利用生物气溶胶采样器,在2016年春、夏、秋和冬季分别采集空气样品;基于传统培养方法获得空气中细菌浓度及纯培养菌株;通过提取基因组DNA、扩增细菌16S rRNA、测序和系统发生树等分子技术研究细菌群落时空动态变化规律;结合环境监测数据,分析影响遗产地空气细菌变化的主要因素。【结果】监测期内,空气细菌浓度在(281.20–1409.20)CFU/m3之间,最高浓度出现在MJ4处的夏季,最低浓度出现在MJO处的春季;具有明显季节性变化特征,在空间层位分布上有所差异,但不显著(P0.05)。培养的细菌菌株经鉴定属于4个门11个属;芽孢杆菌属(Bacillus)、Paenarthrobacter、节杆菌属(Arthrobacter)、薄层菌属(Hymenobacter)和考克氏菌属(Kocuria)等为优势属。【结论】麦积山石窟空气细菌群落结构具有明显的季节性和空间分布动态变化特征;在石窟不同层位,空气中细菌群落分布与相对湿度、温度与降雨量相关;部分细菌种属如芽孢杆菌属、微球菌属(Micrococcus),为壁画及彩塑生物腐蚀的潜在病害菌;麦积山石窟及周边环境空气细菌的监测可为石窟保护和旅游开放管理提供重要参考。     

Measurements of total and culturable bacteria in the alfresco atmosphere using a wet-cyclone sampler

Alfresco (def. clean, outdoor) airborne bacteria were collected with a commercially available wet-cyclone bioaerosol sampler to demonstrate its use, sample processing and resultant observations of total and culturable bacteria in mid-summer in the mid-Willamette River Valley, OR. Some critiques of the system are given. The maximum and minimum total and culturable airborne bacterial concentrations in the samples were 5.9 × 10⁵ and 8.8 × 10² cells m⁻³, and 1.3 × 10⁴ and 3.1 CFU m⁻³, respectively. What is thought to be a diurnal cycle was also observed for both fractions with highest concentrations during the day and lowest at dawn and dusk. The culturable bacteria as a percentage of the total, was maximal at mid-day (≈ 3%) and minimal at early morning and late evening (≈ 0.5–2%). Contrarily, the total bacteria in the downwind dust plume of a grass seed combine was 2.9 × 10⁶ cells m⁻³ and of these approximately 73% were culturable, a much greater culturable percentage than found in the alfresco outdoor atmosphere.     

Incidence of mesoscale convergence lines as input to spruce budworm control strategies

On occasion Greenbank et al. (1980) in their 1973 to 1976 study on spruce budworm moth dispersal in New Brunswick, Canada, detected intense line concentrations of airborne moths crossing special radar observing sites located about 100 km inland from both the Bay of Fundy and the Northumberland Straits. Line concentrations of insects reflect the presence of atmospheric convergence lines. Data from a surface mesonetwork and wind and temperature soundings up to 2 km collected in New Brunswick from 1976 to 1978 around the period of spruce budworm moth activity has revealed sea breeze fronts to be the meteorological origin for the line concentrations of moths. Analysis has shown sea breeze fronts penetrating 80 to 100 km inland in New Brunswick can be expected once or twice each year during the moth dispersal period. An equation for maximum inland penetration was developed which gave a correlation coefficient of 0.78 between predicted and observed inland penetrations with a standard error of 17.5 km. Predicted sea-breeze frontal penetrations of 100 km or more were considered likely to produce a line concentration of moths observable at the radar sited. Using this criteria the prediction scheme delineated four out of the five nights when line concentrations of moths were observed and only over-predicted on one occasion. Thus meteorological data can be used to predict the appearance of line concentrations of spruce budworm moths and so provide input into population redistribution studies and into the development of control strategies directed at the adult budworm.Presented at Eighth International Congress in Biometeorology, 9–14 September 1979, Shefayim, Israel.     

Observations on the use of membrane filtration and liquid impingement to collect airborne microorganisms in various atmospheric environments

The influence of sample-collection-time on the recovery of culturable airborne microorganisms using a low-flow-rate membrane-filtration unit and a high-flow-rate liquid impinger were investigated. Differences in recoveries were investigated in four different atmospheric environments, one mid-oceanic at an altitude of ~10.0 m, one on a mountain top at an altitude of ~3,000.0 m, one at ~1.0 m altitude in Tallahassee, Florida, and one at ~1.0 m above ground in a subterranean-cave. Regarding use of membrane filtration, a common trend was observed: the shorter the collection period, the higher the recovery of culturable bacteria and fungi. These data also demonstrated that lower culturable counts were common in the more remote mid-oceanic and mountain-top atmospheric environments with bacteria, fungi, and total numbers averaging (by sample time or method categories) <3.0 colony-forming units (CFU) m⁻³. At the Florida and subterranean sites, the lowest average count noted was 3.5 bacteria CFU m⁻³, and the highest averaged 140.4 total CFU m⁻³. When atmospheric temperature allowed use, the high-volume liquid impinger utilized in this study resulted in much higher recoveries, as much as 10× greater in a number of the categories (bacterial, fungal, and total CFU). Together, these data illustrated that (1) the high-volume liquid impinger is clearly superior to membrane filtration for aeromicrobiology studies if start-up costs are not an issue and temperature permits use; (2) although membrane filtration is more cost friendly and has a ‘typically’ wider operational range, its limits include loss of cell viability with increased sample time and issues with effectively extracting nucleic acids for community-based analyses; (3) the ability to recover culturable microorganisms is limited in ‘extreme’ atmospheric environments and thus the use of a ‘limited’ methodology in these environments must be taken into account; and (4) the atmosphere culls, i.e., everything is not everywhere.     

Airborne concentrations of bacteria and fungi in Thailand border market

Thailand border market is where the local Thais, Cambodians, Laotians, and Burmeses exchange their goods and culture at the border checkpoints. It is considered to be the source of aerial disease transmission especially for foreigners because it is always very crowded with people from all walks of life. Unhealthy air quality makes this area high risk of spread of airborne diseases. This study assessed airborne concentrations of bacteria and fungi in a border market to improve exposure estimates and develop efficient control strategies to reduce health risk. The density and distribution of airborne bacteria and fungi were investigated in the Chong Chom border market in Surin Province, Thailand. Eighteen air sampling sites were taken from outdoors and various work environments including indoor footpaths, wooden handicraft shops, electronic shops, the secondhand clothing shops, and fruit market areas. Exposed Petri plate method and liquid impinger sampler were used for sampling at the breathing zone, 1.5 m above the floor level, during weekend and holiday. Meteorological factors such as relative humidity, temperature, and light intensity were collected by portable data logger. The relative humidity was 67–73%, and temperature 29–33°C, and light varied between 18 and 270 Lux m⁻². Gram-positive and Gram-negative bacteria were found at a mean value of 10⁴ CFU m⁻³, and airborne fungi of 10³ CFU m⁻³ were recorded. The highest concentration of culturable airborne microorganisms was found along the indoor footpath (9.62 × 10⁴ CFU m⁻³ and 750.00 CFU/plate/h for impingement and sedimentation methods, respectively), the fruit market area (7.86 × 10⁴ CFU m⁻³ and 592.42 CFU/plate/h for impingement and sedimentation methods, respectively), and the secondhand clothing shop (4.59 × 10³ CFU m⁻³ and 335.42 CFU/plate/h for impingement and sedimentation methods, respectively) for Gram-positive bacteria, Gram-negative bacteria, and fungi, respectively. The lowest concentration of Gram-positive bacteria, Gram-negative bacteria, and fungi was found only at the outdoor area at 1.53 × 10⁴ CFU m⁻³, 0.93 × 10⁴ CFU m⁻³ and 0.80 × 10³ CFU m⁻³ by means of impingement method and 136.67 CFU/plate/h, 69.25 CFU/plate/h, and 62.00 CFU/plate/h by means of sedimentation methods for Gram-positive bacteria, Gram-negative bacteria, and fungi, respectively. The most frequently present airborne bacteria were identified as Bacillus, Corynebacteria, Diplococcus, Micrococcus, Acinetobacter, Alcaligenes, Enterobacter, and spore former rods. Acremonium, Aspergillus, Cladosporium, Penicillium, and Sporotrichum were the most frequently found aerosol fungi genera. The distribution of airborne microorganisms correlated with relative humidity and light factors based on principal component analysis. In conclusion, the border market is a potential source of aerial disease transmission and a various hazards of bioaerosols for workers, consumers, sellers, and tourists. The bioaerosol concentration exceeded the standard of occupational exposure limit. Many major indicators of allergenic and toxigenic airborne bacteria and fungi, Acinetobacter, Enterobacter, Pseudomonas, Cladosporium, Alternaria, Aspergillus, and Penicillium, were found in the various market environments.