The relationship between measured moisture conditions and fungal concentrations in water-damaged building materials

We determined the moisture levels, relative humidity (RH) or moisture content (MC) of materials, and concentrations of culturable fungi, actinomycetes and total spores as well as a composition of fungal flora in 122 building material samples collected from 18 moisture problem buildings. The purpose of this work was to clarify if the is any correlation between the moisture parameters and microbial levels or generic composition depending on the type of materials and the time passed after a water damage. The results showed an agreement between the concentrations of total spores and culturable fungi for the wood, wood-based and gypsum board samples (r > 0.47). The concentrations of total spores and/or culturable fungi correlated with RH of materials particularly among the wood and insulation materials (r > 0.79), but not usually with MC (r < 0.45). For the samples collected from ongoing damage, there was a correlation between RH of materials and the concentrations of total spores and culturable fungi (r > 0.51), while such a relationship could not be observed for the samples taken from dry damage. A wide range of fungal species were found in the samples from ongoing damage, whereas Penicillia and in some cases yeasts dominated the fungal flora in the dry samples. This study indicates that fungal contamination can be evaluated on the basis of moisture measurements of constructions in ongoing damage, but the measurements are not solely adequate for estimation of possible microbial growth in dry damage.     

Conventional and toxicogenomic assessment of the acute pulmonary damage induced by the instillation of Cardiff PM10 into the rat lung

There is strong epidemiological evidence of association between PM₁₀ (particulate matter with an aerodynamic diameter less than or equal to 10 μm) and adverse health outcomes including death and increased hospital admissions for cardiopulmonary conditions. Ambient PM₁₀ surrogates such as diesel exhaust particles (DEP), a common component of UK PM_10, have been shown to induce lung inflammation in both humans and rodents. To date, few studies have reported on the toxicological response of UK PM₁₀ in experimental animals.This study examines the pulmonary toxicological responses in male Sprague Dawley rats following the intratracheal instillation of Cardiff urban PM₁₀. A mild but significant change in lung permeability was observed in the lung post-instillation of a high (10 mg) dose of the whole PM₁₀ as adjudged by increases in lung to body weight ratio and total acellular lavage protein. Such effects were less marked following instillation of a water-soluble fraction (80% of the total mass) but histological examination showed that lung capillaries were swollen in size with this treatment.In conclusion, conventional toxicological, histological and toxicogenomic studies have indicated that Cardiff PM₁₀ exhibits low bioreactivity in the form of mild permeability changes. Differential gene expression was observed when the lung was treated with whole PM₁₀, containing durable particles, in comparison with the water-soluble fraction of PM₁₀ that was devoid of particles. Such changes were linked to different histopathological events within the lung.     

Comparison of sampling methods for the assessment of indoor microbial exposure

Abstract Indoor microbial exposure has been related to allergy and respiratory disorders. However, the lack of standardized sampling methodology is problematic when investigating dose-response relationships between exposure and health effects. In this study, different sampling methods were compared regarding their assessment of microbial exposures, including culturable fungi and bacteria, endotoxin, as well as the total inflammatory potential (TIP) of dust samples from Danish homes. The Gesamtstaubprobenahme (GSP) filter sampler and BioSampler were used for sampling of airborne dust, whereas the dust fall collector (DFC), the electrostatic dust fall collector (EDC), and vacuum cleaner were used for sampling of settled dust. The GSP assessed significantly higher microbial levels than the BioSampler, yet measurements from both samplers correlated significantly. Considerably higher levels of fungi, endotoxin, and TIP were found in the EDC compared with the DFC, and regarding fungi, the EDC correlated more strongly and significantly with vacuumed dust than the DFC. Fungi in EDC and vacuum dust correlated most strongly with airborne dust, and in particular, the measurements from the EDC associated well with those from GSP. Settled dust from the EDC was most representative of airborne dust and may thus be considered as a surrogate for the assessment of indoor airborne microbial exposure. PRACTICAL IMPLICATIONS: Significant discrepancies between sampling methods regarding indoor microbial exposures have been revealed. This study thus facilitates comparison between methods and may therefore be used as a frame of reference when studying the literature or when conducting further studies on indoor microbial exposure. Results also imply that the relatively simple EDC method for the collection of settled dust may be used as an alternative to otherwise tedious and time-consuming airborne dust sampling.     

Determination of fungal spore release from wet building materials

The release and transport of fungal spores from water-damaged building materials is a key factor for understanding the exposure to particles of fungal origin as a possible cause of adverse health effects associated to growth of fungi indoors. In this study, the release of spores from nine species of typical indoor fungi has been measured under controlled conditions. The fungi were cultivated for a period of 4-6 weeks on sterilized wet wallpapered gypsum boards at a relative humidity (RH) of approximately 97%. A specially designed small chamber (P-FLEC) was placed on the gypsum board. The release of fungal spores was induced by well-defined jets of air impacting from rotating nozzles. The spores and other particles released from the surface were transported by the air flowing from the chamber through a top outlet to a particle counter and sizer. For two of the fungi (Penicillium chrysogenum and Trichoderma harzianum), the number of spores produced on the gypsum board and subsequently released was quantified. Also the relationship between air velocities from 0.3 to 3 m/s over the surface and spore release has been measured. The method was found to give very reproducible results for each fungal isolate, whereas the spore release is very different for different fungi under identical conditions. Also, the relationship between air velocity and spore release depends on the fungus. For some fungi a significant number of particles smaller than the spore size were released. The method applied in the study may also be useful for field studies and for generation of spores for exposure studies.     

Biodeterioration of sandstone under the influence of different humidity levels in laboratory conditions

Excessive moisture in building materials supports microbial growth. It has been referred that relative humidity more than 55% promotes the microbial growth. To test the effect of different relative humidity tropical chamber test was set up at 52%, 76%, 85% and 96% RH and maximum diversity of fungi was found at 85% and 96% RH. Two fungi Aspergillus sydowi and Aspergillus flavipes were present throughout the course of study from moderate to highly abundant form. It was observed that Fusarium moniliforme, Cephalosporium acremonium, Papulospora sp. proliferated at higher relative humidity (i.e. at 85% and 96.6% RH) and Fusarium roseum, Fusarium oxysporum only at 96% RH level. The relative humidity level lower than 62%, i.e. at 52% level exhibited no fungal growth on sandstone surface during two-year observations. During the study pattern it was noticed that diversity decreased gradually and dominance of particular species increased with the time factor. Analysis of sandstone after fungal colonization by X-ray diffraction and SEM showed the formation of newly formed biomineral.     

Size distribution and chemical composition of airborne particles in south-eastern Finland during different seasons and wildfire episodes in 2006

The inorganic main elements, trace elements and PAHs were determined from selected PM₁, PM_2.5 and PM₁₀ samples collected at the Nordic background station in Virolahti during different seasons and during the wildfire episodes in 2006. Submicron particles are those most harmful to human beings, as they are able to penetrate deep into the human respiratory system and may cause severe health effects. About 70-80%, of the toxic trace elements, like lead, cadmium, arsenic and nickel, as well as PAH compounds, were found in particles smaller than 1 µm. Furthermore, the main part of the copper, zinc, and vanadium was associated with submicron particles. In practice, all the PAHs found in PM₁₀ were actually in PM_2.5. For PAHs and trace elements, it is more beneficial to analyse the PM_2.5 or even the PM₁ fraction instead of PM₁₀, because exclusion of the large particles reduces the need for sample cleaning to minimize the matrix effects during the analysis. During the wildfire episodes, the concentrations of particles smaller than 2.5 µm, as well as those of submicron particles, increased, and also the ratio PM₁/PM₁₀ increased to about 50%. On the fire days, the mean potassium concentration was higher in all particle fractions, but ammonium and nitrate concentrations rose only in particles smaller than 1.0 µm. PAH concentrations rose even to the same level as in winter.     

A comparative study of walking‐induced dust resuspension using a consistent test mechanism

Human walking influences indoor air quality mainly by resuspending dust particles settled on the floor. This study characterized walking‐induced particle resuspension as a function of flooring type, relative humidity (RH), surface dust loading, and particle size using a consistent resuspension mechanism. Five types of flooring, including hardwood, vinyl, high‐density cut pile carpet, low‐density cut pile carpet, and high‐density loop carpet, were tested with two levels of RH (40% and 70%) and surface dust loading (2 and 8 g/m²), respectively. Resuspension fraction r_a (fraction of surface dust resuspended per step) for house dust was found to be varied from 10^?7 to 10^?4 (particle size: 0.4–10 µm). Results showed that for particles at 0.4–3.0 µm, the difference in resuspension fraction between carpets and hard floorings was not significant. For particles at 3.0–10.0 µm, carpets exhibited higher resuspension fractions compared with hard floorings. Increased RH level enhanced resuspension on high‐density cut pile carpet, whereas the opposite effect was observed on hard floorings. Higher surface dust loading was associated with lower resuspension fractions on carpets, while on hard floorings the effect of surface dust loading varied with different RH levels.     

Observational scores of dampness and mold associated with measurements of microbial agents and moisture in three public schools

We examined associations between observational dampness scores and measurements of microbial agents and moisture in three public schools. A dampness score was created for each room from 4‐point‐scale scores (0–3) of water damage, water stains, visible mold, moldy odor, and wetness for each of 8 room components (ceiling, walls, windows, floor, ventilation, furniture, floor trench, and pipes), when present. We created mixed microbial exposure indices (MMEIs) for each of 121 rooms by summing decile ranks of 8 analytes (total culturable fungi; total, Gram‐negative, and Gram‐positive culturable bacteria; ergosterol; (1→3)‐β‐D‐glucan; muramic acid; and endotoxin) in floor dust. We found significant (P ≤ 0.01) linear associations between the dampness score and culturable bacteria (total, Gram‐positive, and Gram‐negative) and the MMEIs. Rooms with dampness scores greater than 0.25 (median) had significantly (P < 0.05) higher levels of most microbial agents, MMEIs, and relative moisture content than those with lower scores (≤0.25). Rooms with reported recent water leaks had significantly (P < 0.05) higher dampness scores than those with historical or no reported water leaks. This study suggests that observational assessment of dampness and mold using a standardized form may be valuable for identifying and documenting water damage and associated microbial contamination.     

Exposure matrices of endotoxin, (1 → 3)-β-d-glucan, fungi, and dust mite allergens in flood-affected homes of New Orleans

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

PM10 composition during an intense Saharan dust transport event over Athens (Greece)

The influence of Saharan dust on the air quality of Southern European big cities became a priority during the last decade. The present study reports results on PM₁₀ monitored at an urban site at 14 m above ground level during an intense Saharan dust transport event. The elemental composition was determined by Energy Dispersive X-ray Fluorescence Spectrometry (EDXRF) for 12 elements: Si, Al, Fe, K, Ca, Mg, Ti, S, Ni, Cu, Zn and Mn. PM₁₀ concentrations exceeded the EU limit (50 μg/m³) several times during the sampling period. Simultaneous maxima have been observed for the elements of crustal origin. The concentrations of all the elements presented a common maximum, corresponding to the date where the atmosphere was heavily charged with particulate matter permanently for an interval of about 10 h. Sulfur and heavy metal concentrations were also associated to local emissions. Mineral dust represented the largest fraction of PM₁₀ reaching 79%. Seven days back trajectories have shown that the air masses arriving over Athens, originated from Western Sahara. Scanning Electron Microscopy coupled with Energy Dispersive X-ray analysis (SEM-EDX) revealed that particle agglomerates were abundant, most of them having sizes < 2 μm. Aluminosilicates were predominant in dust particles also rich in calcium which was distributed between calcite, dolomite, gypsum and Ca-Si particles. These results were consistent with the origin of the dust particles and the elemental composition results. Sulfur and heavy metals were associated to very fine particles < 1 μm.     

Indoor air quality in Portuguese schools: levels and sources of pollutants

Indoor air quality (IAQ) parameters in 73 primary classrooms in Porto were examined for the purpose of assessing levels of volatile organic compounds (VOCs), aldehydes, particulate matter, ventilation rates and bioaerosols within and between schools, and potential sources. Levels of VOCs, aldehydes, PM_2.5, PM₁₀, bacteria and fungi, carbon dioxide (CO₂), carbon monoxide, temperature and relative humidity were measured indoors and outdoors and a walkthrough survey was performed concurrently. Ventilation rates were derived from CO₂ and occupancy data. Concentrations of CO₂ exceeding 1000 ppm were often encountered, indicating poor ventilation. Most VOCs had low concentrations (median of individual species <5 μg/m³) and were below the respective WHO guidelines. Concentrations of particulate matter and culturable bacteria were frequently higher than guidelines/reference values. The variability of VOCs, aldehydes, bioaerosol concentrations, and CO₂ levels between schools exceeded the variability within schools. These findings indicate that IAQ problems may persist in classrooms where pollutant sources exist and classrooms are poorly ventilated; source control strategies (related to building location, occupant behavior, maintenance/cleaning activities) are deemed to be the most reliable for the prevention of adverse health consequences in children in schools.     

Residential culturable fungi, (1‐3, 1‐6)‐β‐d‐glucan,and ergosterol concentrations in dust are not associated with asthma,rhinitis, or eczema diagnoses in children

Qualitative reporting of home indoor moisture problems predicts respiratory diseases. However, causal agents underlying such qualitative markers remain unknown. In the homes of 198 multiple allergic case children and 202 controls in Sweden, we cultivated culturable fungi by directly plating dust, and quantified (1‐3, 1‐6)‐β‐d ‐glucan and ergosterol in dust samples from the child's bedroom. We examined the relationship between these fungal agents and degree of parent or inspector‐reported home indoor dampness, and microbiological laboratory's mold index. We also compared the concentrations of these agents between multiple allergic cases and healthy controls, as well as IgE‐sensitization among cases. The concentrations of culturable fungal agents were comparable between houses with parent and inspector‐reported mold issues and those without. There were no differences in concentrations of the individual or the total summed culturable fungi, (1‐3, 1‐6)‐β‐d ‐glucan, and ergosterol between the controls and the multiple allergic case children, or individual diagnosis of asthma, rhinitis, or eczema. Culturable fungi, (1‐3, 1‐6)‐β‐d ‐glucan, and ergosterol in dust were not associated with qualitative markers of indoor dampness or mold or indoor humidity. Furthermore, these agents in dust samples were not associated with any health outcomes in the children.     

Indoor air quality in schools of a highly polluted south Mediterranean area

This study aimed at surveying lower secondary schools in southern Italy, in a highly polluted area. A community close to an industrial area and three villages in rural areas was investigated. Indoor temperature, relative humidity (RH), gaseous pollutants (CO₂ and NO₂), selected biological pollutants in indoor dust, and the indoor/outdoor mass concentration and elemental composition of PM_2.5 were ascertained. Temperature and RH were within, or close to, the comfort range, while CO₂ frequently exceeded the threshold of 1000 ppm, indicating inadequate air exchange rate. In all the classrooms, median NO₂ levels were above the WHO threshold value. Dermatophagoides p. allergen concentration was below the sensitizing threshold, while high endotoxin levels were detected in the classrooms, suggesting schools may produce significant risks of endotoxin exposure. Concentration and solubility of PM_2.5 elements were used to identify the sources of indoor particles. Indoor concentration of most elements was higher than outdoors. Resuspension was responsible for the indoor increase in soil components. For elements from industrial emission (Cd, Co, Ni, Pb, Sb, Tl, V), the indoor concentration depended on penetration from the outside. For these elements, differences in rural vs industrial concentrations were found, suggesting industrial sources may influence indoor air quality nearby schools.     

Heat transfer and thermal storage behaviour of gypsum boards incorporating micro-encapsulated PCM

In the application of energy storage and thermal environmental control, PCM (Phase Change Material) is a very promising material choice. This study incorporated mPCM (micro-encapsulated PCM) into gypsum to make mPCM gypsum board and then investigated the physical properties, heat transfer and thermal storage behaviour. The major control parameters are wall temperatures and the weight percentages of mPCM added to the gypsum boards. A melting fraction correlation, reduced from our test data and based on Stefan number (Ste), subcooling (Sb) and Fourier number, is proposed. It shows that case with a higher Ste or Sb can have a higher heat transfer through the hot wall. Thermal storage behaviour of mPCM gypsum boards is then analyzed.     

Fungal extracellular polysaccharides, beta (1-->3)-glucans and culturable fungi in repeated sampling of house dust

Fungal exposure inside homes has been associated with adverse respiratory symptoms in children and adults. While fungal assessment has traditionally relied upon questionnaires, fungal growth on culture plates and spore counts, new immunoassays for extracellular polysaccharides (EPS) and beta (1-->3)-glucans have enabled quantitation of fungal agents in house dust in a more timely and cost-effective manner, possibly providing a better measure of fungal exposure. We investigated associations among measurements of EPS, beta (1-->3)-glucans and culturable fungi obtained from 23 Dutch homes. From each home, dust samples were vacuumed from the living room floor twice during the Fall, Winter and Spring seasons for a total of six collections (every 6 weeks from October 1997 to May 1998). Samples were sieved and fine dust was analyzed for EPS from Aspergillus and Penicillium spp. combined, beta (1-->3)-glucans and culturable fungi. EPS was positively associated with glucan; an increase from the 25th to the 75th percentile of glucan concentration was associated with a 1.6-fold increase in EPS concentration (95% CI = 1.3 to 2.0; p < 0.01). The most significant variables associated with EPS and glucan concentrations were the surface type that was vacuumed and the concentration of total culturable fungi (in colony forming units (CFU)/g dust), with an increase in CFU/g from the 25th to the 75th percentile associated with a 1.3 (1.1-1.6)-fold increase in glucan and a 1.7 (1.3-2.2)-fold increase in EPS concentrations. In addition, the within-home variation of EPS levels were smaller than those between homes (25,646 U/g vs. 50,635 U/g), whereas the variation of glucan levels was similar within and between homes (1,300 vs. 1,205 micrograms/g). These positive associations suggest that house dust concentrations of beta (1-->3)-glucan, and particularly those of EPS, are good markers for the overall levels of fungal concentrations in floor dust which is a surrogate for estimating airborne fungal exposure.     

Non-exhaust emissions of PM and the efficiency of emission reduction by road sweeping and washing in the Netherlands

From research on PM_2.5 and PM₁₀ in 2007/2008 in the Netherlands, it was concluded that the coarse fraction (PM_2.5-10) attributed 60% and 50% respectively, to the urban-regional and street-urban increments of PM₁₀. Contrary to Scandinavian and Mediterranean countries which exhibit significant seasonal variation in the coarse fraction of particulate matter (PM), in the Netherlands the coarse fraction in PM at a street location is rather constant during the year. Non-exhaust emissions by road traffic are identified as the main source for coarse PM in urban areas. Non-exhaust emissions mainly originate from re-suspension of accumulated deposited PM and road wear related particles, while primary tire and brake wear hardly contribute to the mass of non-exhaust emissions. However, tire and brake wear can clearly be identified in the total mass through the presence of the heavy metals: zinc, a tracer for tire wear and copper, a tracer for brake wear.The efficiency of road sweeping and washing to reduce non-exhaust emissions in a street-canyon in Amsterdam was investigated. The increments of the coarse fraction at a kerbside location and a housing façade location versus the urban background were measured at days with and without sweeping and washing. It was concluded that this measure did not significantly reduce non-exhaust emissions.     

Domestic exposure to fungal allergenic particles determined by halogen immunoassay using subject's serum versus particles carrying three non‐fungal allergens determined by allergen‐specific HIA

Studies that estimate indoor aeroallergen exposure typically measure a pre‐selected limited range of allergens. In this study, inhalable aeroallergen particles were quantified using the halogen immunoassay (HIA) to determine the contribution of fungal and non‐fungal aeroallergens to total allergen exposure. Bioaerosols from 39 homes of fungal‐allergic subjects were sampled using inhalable fraction samplers and immunostained by HIA using resident subject's immunoglobulin E (IgE) to detect allergen‐laden particles. Fungal aerosols as well as particles carrying mite, cat, and cockroach allergens were identified and enumerated by HIA. Reservoir dust‐mite (Der p 1), cat (Fel d 1), and cockroach (Bla g 1) allergen concentrations were quantified by ELISA. Fungal particles that bound subject's IgE in the HIA were 1.7 (bedroom)‐ and 1.4 (living room)‐fold more concentrated than Der p 1, Fel d 1, and Bla g 1 allergen particles combined. Predominant fungal conidia that bound IgE were derived from common environmental genera including Cladosporium and other fungi that produce amerospores. Airborne mite, cat, and cockroach allergen particle counts were not associated with reservoir concentrations determined by ELISA. This study demonstrates that inhalable fungal aerosols are the predominant aeroallergen sources in Sydney homes and should be considered in future exposure assessments.     

Exercise‐induced effects on a gym atmosphere

We report results of analysis of a month‐long measurement of indoor air and environment quality parameters in one gym during sporting activities such as football, basketball, volleyball, badminton, boxing, and fitness. We have determined an average single person's contribution to the increase of temperature, humidity, and dust concentration in the gym air volume of 12500 m³: during 90‐min exercise performed at an average heart rate of 143 ± 10 bpm, a single person evaporated 0.94 kg of water into the air by sweating, contributed 0.03 K to the air temperature rise and added 1.5 μg/m³ and 5 ng/m³ to the indoor concentration of inhalable particles (PM₁₀) and Ca concentration, respectively. As the breathing at the observed exercise intensity was about three times faster with respect to the resting condition and as the exercise‐induced PM₁₀ concentration was about two times larger than outdoors, a sportsman in the gym would receive about a sixfold higher dose of PM₁₀ inside than he/she would have received at rest outside.     

Origins of n-alkanes, carbonyl compounds and molecular biomarkers in atmospheric fine and coarse particles of Athens, Greece

The abundance and origin of aliphatic hydrocarbons, carbonyl compounds and molecular biomarkers found in the aliphatic fraction of PM_10-2.5 and PM_2.5 in the centre of Athens Greece are discussed in an attempt to reveal seasonal air pollution characteristics of the conurbation. Each extract was fractionated into individual compound classes and was analyzed using gas chromatography coupled to mass spectrometry. Normal alkanes, ranging from C₁₄ to C₃₅, were abundant in PM_10-2.5 and PM_2.5 samples during both sampling campaigns. The daily concentration of total n-alkanes was up to 438 ng m^− 3 for PM_10-2.5 and up to 511 ng m^− 3 for PM_2.5. Additionally, gaseous concentrations of n-alkanes were calculated, revealing that the relative proportions between gaseous and particle phases of individual compounds may differ significantly between summer and late winter. Normal alkanals and alkan-2-ones were only detected in the fine fraction of particulate matter and their concentrations were much lower than the n-alkane concentrations. Several geochemical parameters were used to qualitatively reconcile the sources of organic aerosol. The carbon preference index (CPI) of the coarse particles in August had the highest value, while in March the leaf wax contribution decreased significantly and the CPI value was very close to unity for both sites. Maximum concentrations of carbonyl compounds were reported in the range of C₁₅-C₂₀, demonstrating that they were formed from anthropogenic activity or from atmospheric oxidative processes. 6, 10, 14-trimethylpentadecan-2-one, a marker of biogenic input, was also detected in our samples. Molecular biomarker compounds confirmed that ca. 60% of the aliphatic fraction on the sampled atmospheric particles originated from petroleum and not from any contemporary biogenic sources. Pristane and phytane were detected in the fine fraction with their presence indicating sources of fossil fuel in the range of C₁₆-C₂₀. At all sites the 17α(Η),21β(Η) hopane series was the most abundant hopane group.     

Concentration and size distribution of bioaerosols in an outdoor environment in the Qingdao coastal region

Bioaerosol particles in the atmosphere were collected from the coastal region of Qingdao from Jul. 2009 to Jun. 2010. The concentrations of microorganisms (including culturable, nonculturable, terrestrial and marine microorganisms) were measured. Average concentrations of airborne terrestrial bacteria, marine bacteria, terrestrial fungi, marine fungi and total bioaerosol were in the ranges of 33-664 CFU/m³, 63-815 CFU/m³, 2-777 CFU/m³, 66-1128 CFU/m³ and 85,015-166,094 Cells/m³, respectively. The nonculturable microbes accounted for 99.13% of the total microbes. In addition, there were more culturable marine microbes than culturable terrestrial microbes, and more airborne fungi than bacteria. The concentration of airborne bacteria showed a skewed distribution pattern, while unimodal size distributions were observed for the concentrations of fungi and total microbes. The airborne microbes mainly existed in > 2.1 μm coarse particles. Pearson correlation analysis between the concentrations and meteorological parameters showed that the meteorological parameters had different effects on different kinds of microbes. Sandstorms increased the concentrations of both culturable microbes and total microbes in the bioaerosol.