Do exposures to aerosols pose a risk to dental professionals?

BACKGROUND: Dental care professionals are exposed to aerosols from the oral cavity of patients containing several pathogenic microorganisms. Bioaerosols generated during dental treatment are a potential hazard to dental staff, and there have been growing concerns about their role in transmission of various airborne infections and about reducing the risk of contamination. AIMS: To investigate qualitatively and quantitatively the bacterial and fungal aerosols before and during clinical sessions in two dental offices compared with controls. METHODS: An extra-oral evacuator system was used to measure bacterial and fungal aerosols. Macroscopic and microscopic analysis of bacterial species and fungal strains was performed and strains of bacteria and fungi were identified based on their metabolic properties using biochemical tests. RESULTS: Thirty-three bioaerosol samples were obtained. Quantitative and qualitative evaluation showed that during treatment, there is a significant increase in airborne concentration of bacteria and fungi. The microflora included mainly gram-positive organisms (Staphylococcus epidermidis and Micrococcus spp.), gram-positive rod-shaped bacteria and those creating endospores as well as non-porous bacteria and mould fungi (Cladosporium and Penicillium). CONCLUSIONS: Exposure to the microorganisms identified is not a significant occupational hazard for dental care professionals; however, evidence-based prevention measures are recommended.

Investigation of winter atmospheric aerosol particles in downtown Katowice using XPS and SEM.

X-ray photoelectron spectroscopy (XPS) was used to determine the surface chemical composition of atmospheric particles (PM-10 and PM-2.5), collected in downtown Katowice, Upper Silesia, Poland, in the winter season (November and December 2000). Carbon- and oxygen-containing species dominated the particulate surface with traces of N, S, Si, Cl, Na, Zn, Al, Cu, Fe, Ca, K, Mg, Pb, and P present. Additionally, the size, morphology, and chemical composition of about 300 of the individual atmospheric particles were analyzed by high-resolution scanning electron microscopy and electron probe microanalysis. A number of aluminosilicates and metallic elements such as Fe, K, Mg, Zn, as well as rare earth elements, were detected by SEM. The results obtained show that the analyzed aerosol is of natural and anthropogenic origin. Particles containing sulfur compounds as well as oxygen and sodium in downtown Katowice come mainly from the east and southeast sectors.

Optical and chemical characteristics of the atmospheric aerosol in four towns in southern Poland.

The absorption coefficient a(p) [m(-1)] as well as the mass absorption coefficient sigma(p) [m(2)/g] has been estimated for PM10 and PM2.5 in four towns located in southern Poland, based on the assumption that the reflectance of aerosol-laden filters is a good proxy for the absorptivity of aerosols. The optical properties of the airborne particles were also compared with their surface composition obtained by photoelectron spectroscopy (XPS). It was found that coarse particles, which constituted 20-30% of PM10, exhibited insignificant contribution to the absorption. The most absorptive aerosols were found in the towns located in Upper Silesia, a highly industrialized area. This reflects both the relative content of carbon in PM2.5 and the mass concentration of the fine mode. It was found that oxides and sulfates play an important role in promoting the reflectance of light from aerosols in the winter. These results support the suggestion that the revision of existing air quality standards for particulate pollution is needed.

A study of fibrous aerosols in the home environment in Sosnowiec, Poland.

This work constitutes the first report on the concentration of airborne respirable fibers, and their length distribution in different groups of homes in Sosnowiec, Poland. The measurements have been made by using the MIE Laser Fiber Monitor FM-7400. Mean concentration level of the respirable fibers, longer than 5 microns, ranged from 350 m-3 through 910 m-3 up to 1020 m-3 in the homes located in suburban areas, near the busy streets, and in the buildings covered with asbestos-cement sheets, respectively. These results indicate the outdoor asbestos-containing materials as the main sources of airborne fibers inside the Sosnowiec dwellings.

[The prevalence of bacterial and fungal aerosol in homes, offices and ambient air of Upper Silesia. Preliminary results]. / Wystepowanie aerozolu bakteryjnego i grzybowego w mieszkaniach, biurach i srodowisku zewnetrznym Górnego Slaska. Wyniki Wstepne.

Quantitative criteria of microbiological air quality in homes and offices are needed for practical reasons. The purpose of this study was to obtain the preliminary characteristic of bacterial and fungal aerosols in healthy buildings. It was analysed the concentrations levels and size distributions of the investigated bioaerosols. The obtained data can be treated as a first step in the direction of determining so called normal level for different bioaerosols in homes and offices in Poland. The concentrations of airborne bacteria and fungi were measured using 6-stage Andersen impactor. The Trypcase Soy Agar were applied for bacteria and 2% Malt Extract Agar for fungi. The bacteria samples were incubated for 2 days at 37 degrees C and the fungi samples respectively for 4 days at 25 degrees C. The indoor levels of bacterial aerosol (homes: 212-888 cfu/m3, offices: 136-542 cfu/m3) were higher than the outdoor levels (respectively: 42-386 cfu/m3 and 13-115 cfu/m3). The fungal aerosol concentrations were lower indoors (homes: 81-383 cfu/m3, offices: 18-133 cfu/m3) than outdoors (94-625 cfu/m3). There were distinctly higher concentrations of the investigated bioaerosols in homes than in offices. The aerodynamic diameter of most bacterial particles were higher than 7 microns, both in indoor air (homes: 57-260 cfu/m3, offices 19-118 cfu/m3) and outdoor air (respectively: 9-145 cfu/m3 and 0-71 cfu/m3). The maximum for fungal spore levels were observed in the size range 3.3-4.7 and 2.1-3.3 microns in the instance of homes (respectively: 12-155 cfu/m3 and 19-154 cfu/m3) and in the size range 2.1-3.3 microns in the instance of offices (6-55 cfu/m3). Largest numbers of this bioaerosol in outdoor air were isolated in the size range 2.1-3.3 microns (25-208 cfu/m3). Although there are some proposals for an upper limit of the normal indoor concentration of airborne bacteria and fungi, but due to different climate and housing conditions we can expect other normal range of fungal and bacterial aerosol in Polish homes.

[Dust particles and metals in outdoor and indoor air of Upper Silesia]. / Czastki pylu i metale w powietrzu zewnetrznym i w pomieszczeniach na Górnym Slasku.

This work contains the results of the aerosol mass size distribution and preliminary studies on concentrations and size distribution of heavy metals (Pb, Zn, Cu, Mn, Fe and Cd) in indoor and outdoor environment in Upper Silesia (the highly industrialized region in the southern part of Poland). In studies, the measurements of aerosol concentration, mass size distribution, and evaluation of heavy metals concentration were made from December 1992 to April 1994 in some apartments in five towns in Upper Silesia and in one village in the Beskidy Mountains in both indoor and outdoor environments. The particles were fractionated in Andersen cascade impactor. The sampling time was 6-7 days and 4-5 days for indoor and outdoor respectively. Aerosol particulates were collected on A-type glass fiber collection substrate used later for determination of heavy concentrations by atomic absorption spectrophotometry (AAS 3, Carl Zeiss Jena). The dust was mineralized by the means of the mixture of hydrofluoric and nitric acids. The results of mass size distribution as well as the measurements of TSP for indoor and outdoor aerosol show that the main source of particulate matter indoors, in this region, are heavy polluted outdoor air and cigarette smoking. It can be said that, except homes in Knurów and Sosnowiec with hard smokers, the indoor levels of particulate pollution were significant lower than the outdoors levels. Whenever in the indoor environment appear additional source of particulate emission situation can changed. When we compare mass size distribution for outdoor aerosol and indoor aerosol contaminated by tobacco smoke, we can observed considerable increase of indoor aerosol level in the 0.33-0.54 microns size range. Besides, indoor aerosol status may be changed by coal stove emission (displacement of maximum peak to direction of coarse particles). The observed differences in concentration of particulate matter may also indicate the important differences in chemical and physical nature of particles caused by the air filtration and absorption during migration of ambient air into the indoor environment. On the base of comparison of the heavy metals concentrations of fine and coarse fraction and their indoor/outdoor ratio in five selected towns in Upper Silesia it can be said that the level of heavy metals in indoor aerosol is lower than in outdoor (except Pb and Cd) what suggest that migration of ambient air into the homes is a major process which give indoor air contamination of heavy metals.(ABSTRACT TRUNCATED AT 400 WORDS)