Pyrogenic activity of air to characterize bioaerosol exposure in public buildings: a pilot study

Assessment of fungal bioaerosols and particulate matter characteristics in indoor and outdoor air of veterinary clinics

Veterinary staff are frequently exposed to various occupational hazards. The present study was aimed to investigate the air characteristics of veterinary clinics in terms of fungal bioaerosols and particulate matters. Air samples were taken every six days from the operating room, examination room and outdoor air of three veterinary clinics in Shiraz, southwest Iran. The concentrations of fungal bio-aerosols ranged from 8.05 CFU/m ³ in the outdoor air of clinic B to 47.21 CFU/m ³ in the operating room of clinic A. The predominant fungal genera identified in the studied clinics were Penicillium and Aspergillus niger, respectively. The concentrations of PM_2.5 ranged from 41.88 μg/m ³ in the operating room of clinic C to 60.31 μg/m ³ in the outdoor air of the same clinic. The corresponding values for PM₁₀ ranged from 114.40 μg/m ³ in the operating room of clinic C to 256.70 μg/m ³ in the outdoor air of the same clinic. The results of this study showed a positive correlation between the concentration of fungal bioaerosols and relative humidity (p < 0.05; r = 0.622). Besides, a negative correlation was found between the concentration of fungal bioaerosols and temperature (p < 0.05; r = 0.369). To better assess the individual exposure of veterinarians and staff in veterinary clinics, tests including nasopharyngeal sampling are recommended.

Bacterial Contamination in Health Care Centers: Differences between Urban and Rural Settings

This study aims to assess the airborne bioburden of rural and urban Portuguese Primary Health Care Centers (PHCC) using active and passive sampling methods and identify the potential differences in airborne microbiota between both environments. The highest total aerobic mesophilic bacterial load in indoor air were found in the Vaccination Room (448 CFU.m−3) in the Rural PHCC and in the Waiting Room (420 CFU.m−3) for Urban PHCC. The total coliforms contamination level in indoor air was detected only in the Cleaning Supplies Room (4 CFU.m−3) in the Urban PHCC. The most frequent bacteria genera identified was Micrococcus (21% Rural PHCC; 31% Urban PHCC). The surface samples showed a highest total aerobic mesophilic bacterial contamination in the Treatment Room (86 × 103 CFU.m−2) from the Rural PHCC and in the Front Office (200 × 103 CFU.m−2) from the Urban PHCC. The electrostatic dust cloth (EDC) samples showed a highest bacterial load in the Urban PHCC. Total aerobic mesophilic bacterial load in settled dust and in the Heating, Ventilating and Air Conditioning (HVAC) filter samples in the Urban PHCC (8 CFU.g−1 and 6 × 103 CFU.m−2) presented higher values compared with the Rural PHCC (1 CFU.g−1 and 2.5 × 103 CFU.m−2). Urban PHCC presented higher bacterial airborne contamination compared with the Rural PHCC for the majority of sampling sites, and when compared with the indoor air quality (IAQ) Portuguese legislation it was the Rural PHCC in two sampling places who did not comply with the established criteria.

Application of Airborne Microorganism Indexes in Offices, Gyms, and Libraries

The determination of microbiological air quality in sporting and working environments requires the quantification of airborne microbial contamination. The number and types of microorganisms, detected in a specific site, offer a useful index for air quality valuation. An assessment of contamination levels was carried out using three evaluation indices for microbiological pollution: the global index of microbiological contamination per cubic meter (GIMC/m3), the index of mesophilic bacterial contamination (IMC), and the amplification index (AI). These indices have the advantage of considering several concomitant factors in the formation of a microbial aerosol. They may also detect the malfunction of an air treatment system due to the increase of microbes in aeraulic ducts, or inside a building compared to the outdoor environment. In addition, they highlight the low efficiency of a ventilation system due to the excessive number of people inside a building or to insufficient air renewal. This study quantified the levels of microorganisms present in the air in different places such as offices, gyms, and libraries. The air contamination was always higher in gyms that in the other places. All examined environments are in Northern Italy.

Microbiological air quality in office buildings equipped with dventilation systems

Proper hygienic conditions in office buildings are of a high importance for both health and well-being of the employees. The aim of this study was the direct comparison of different ventilation systems on microbiological environments in 15 office buildings. The results showed that both bacterial and fungal concentrations in the naturally ventilated office buildings were between 70 and 1600 cfu/m³ , while in the offices equipped with air-conditioning and mechanical ventilation systems, concentrations were lower, that is, between 10 and 530 cfu/m³ and 20 and 410 cfu/m³ , respectively. The size distribution analysis revealed that microorganisms were present in the air mainly as single cells (1.1-3.3 μm) and large aggregates (4.7->7 μm). If deposited in the human respiratory tract, they may be responsible for nose and eyes irritations, asthmatic reactions, and allergic inflammations. The most prevalent bacterial species indoors were Gram-positive cocci (mainly from Staphylococcus and Micrococcus/Kocuria genera) and endospore-forming Gram-positive rods (from Bacillus genus). Among the most common fungal species were those from genera Penicillium, Aspergillus, and Cladosporium. Effectively working and regularly maintained mechanical ventilation or air-conditioning systems ensure a better hygienic quality in the office buildings than natural/gravitational ventilation.

Assessment of airborne bacteria in selected occupational environments in Quezon City, Philippines

Exposure to bioaerosols has been associated with health deterioration among workers in several occupational environments. This highlights the need to study the microbiological quality of air of workplaces as no such study has been conducted yet in the Philippines. To detect and characterize the culturable mesophilic airborne bacteria in selected occupational environments we used passive sedimentation technique. It was observed that the number of colony-forming units was highest in junk shop, followed by the light railway transit station and last the office. By contrast, the bacterial composition was similar in all sites: Gram-positive cocci > Gram-positive bacilli > Gram-negative bacteria. Staphylococcus aureus and Bacillus spp. were also detected in all sites. These findings suggest that the presence of airborne bacteria may be a potential health hazard in urban occupational environments in the Philippines.

Whole Blood Cytokine Response to Local Traffic-Related Particulate Matter in Peruvian Children With and Without Asthma

This study sought to investigate if acute phase immune responses of whole blood from Peruvian children with controlled and uncontrolled asthma differed from children without asthma, following exposure to traffic-related particulate matter (TRPM). TRPM, including particulate matter from diesel combustion, has been shown to stimulate acute airway inflammation in individuals with and without asthma. For this study, a whole blood assay (WBA) was used to test peripheral whole blood samples from 27 children with asthma, and 12 without asthma. Participant blood samples were stimulated, ex vivo, for 24-h with an aqueous extract of TRPM that was collected near study area highways in Lima, Peru. All participant blood samples were tested against the same TRPM extract, in addition to purified bacterial endotoxin and pyrogen-free water, which served as positive and negative WBA controls, respectively. The innate and adaptive cytokine responses were evaluated in cell-free supernatants of the whole blood incubations. Comparatively similar levels were recorded for nine out of the 10 cytokines measured [e.g., – Interleukin (IL)-1β, IL-6, IL-10], regardless of study participant asthma status. However, IL-8 levels in TRPM-stimulated blood from children with uncontrolled asthma were diminished, compared to subjects without asthma (633 pg/ml vs. 1,023 pg/ml, respectively; p < 0.01); IL-8 responses for subjects with controlled asthma were also reduced, but to a lesser degree (799 pg/ml vs. 1,023 pg/ml, respectively; p = 0.10). These relationships were present before, and after, adjusting for age, sex, obesity/overweight status, C-reactive protein levels, and residential proximity to the study area’s major roadway. For tests conducted with endotoxin, there were no discernible differences in cytokine response between groups, for all cytokines measured. The WBA testing conducted for this study highlighted the capacity of the TRPM extract to potently elicit the release of IL-8 from the human whole blood system. Although the small sample size of the study limits the capacity to draw definitive conclusions, the IL-8 responses suggest that that asthma control may be associated with the regulation of a key mediator in neutrophil chemotaxis, at a systemic level, following exposure to PM derived from traffic-related sources.

Evaluation of microbiological air quality and of microclimate in university classrooms

The proliferation of air-diffused microorganisms inside public buildings such as schools, hospitals, and universities, is often indicated as a possible health risk. In this research, we have illustrated the results of an investigation realized to determine the health of the air in some university classrooms, both from a microbiological and a microclimatic viewpoint, during the normal didactic activity of direct lessons. The results obtained have been expressed by means of contamination indices, already used in previous works. Very little contamination was recorded in the different phases of air treatment, which underlines the efficiency of the system and of the maintenance protocols. The Global Index of Microbial Contamination (GIMC per cubic meter) showed a value greater than the mean during the heating period (290), while the highest values (95th percentile 1,138.45) were recorded in the period using air conditioning. The index of mesophilic bacterial contamination, though it did not show any significant differences in the various modes of air treatment, showed a mean value (1.34) and the 95th percentile value (4.14), which was greater in the air-conditioning phase. Finally, the mean value of the amplification index underlined a decrease in the microbial contamination in comparison to the outside, while showing situations of increased microbial amplification during the period of simple ventilation (95th percentile 4.27). The 95th percentile values found for GICM in the three sampling periods, however, permitted us to identify the value of GIMC per cubic meter equal to 1,000 as a guide to provide a means of self-monitoring the quality of the air inside the classrooms. From a microclimatic viewpoint, two periods of the year manifested discomfort situations: during the heating phase (winter) and during the simple ventilation phase (spring). The results obtained indicate, therefore, a need to intervene on the environmental parameters, not being able, in this particular case, to intervene on other aspects that influence the microclimate.