This paper presents the results of the laboratory evaluation of the Ultraviolet Aerodynamic Particle Size Spectrometer, the novel instrument for real-time continues monitoring of bioaerosols. The main focus of this study was on evaluating selectivity, sensitivity, counting efficiency, and the detection limits of the UV APS.The tests were performed with two types of aerosols, bacterial (e.g., Bacillus sub ti/is spores or vegetative cells, and Pseudomonas fluorescens) and nou-bacterial (e.g., NaCl, latex, peptone water, and nutrient agar/broth). To control viability of airborne bacteria, the bioaerosols were simultaneously sampled with the AGI-30 irnpingers. The study has demonstrated the UV APS cross-sensitivity to the non-bacterial organic materials and the rieec! for careful preparation (washing) of test bacteria, in order to avoid the interfere~e with the fiuoresceuce signals of nutrient media used to grow bacteria. The results were indicative of strong sensitivity of the UV APS to the type of airborne bacteria. The limitations in the capability of the UV APS to measure bacterial spores were also found. Counting efficiency of the fluorescent particles was shown to depend on particle concentration with the upper limit of detection of the UVAPS approximately 6 x 10 7 particles/m 3 .Crown
A new personal bioaerosol sampler has recently been developed and evaluated for sampling of viable airborne bacteria and fungi under controlled laboratory conditions and in the field. The operational principle of the device is based on the passage of air through porous medium immersed in liquid. This process leads to the formation of bubbles within the filter as the carrier gas passes through and thus provides effective mechanisms for aerosol removal. As demonstrated in previous studies, the culturability of sampled bacterium and fungi remained high for the entire 8-h sampling period. The present study is the first step of the evaluation of the new sampler for monitoring of viable airborne viruses. It focuses on the investigation of the inactivation rate of viruses in the bubbling process during 4 h of continuous operation. Four microbes were used in this study, influenza, measles, mumps, and vaccinia viruses. It was found that the use of distilled water as the collection fluid was associated with a relatively high decay rate. A significant improvement was achieved by utilizing virus maintenance fluid prepared by using Hank's solution with appropriate additives. The survival rates of the influenza, measles, and mumps viruses were increased by 1.4 log, 0.83 log, and 0.82 log, respectively, after the first hour of operation compared to bubbling through the sterile water. The same trend was observed throughout the entire 4-h experiment. There was no significant difference observed only for the robust vaccinia virus.
This paper studies the detection limit, selectivity and counting efficiency of an ultraviolet aerodynamic particle sizer spectrometer (UVAPS) with regard to aerosolized fungal spores. The study demonstrated the ability of the instrument for detection and measurement of fungal spores under controlled conditions. A reasonable correlation was found between the UVAPS and the AGI-30 impinger in measuring the aerosol fungal spore concentrations under investigation: Penicillium and Aspergillus niger (r = 0.911, p < 0.005 and r = 0.882, p < 0.05, respectively). A linear relationship between total particle concentration and fluorescent particle concentration was found in the range from 0 to 70 particles/cm 3 . Its lower detection limit was found to be 0.01 particles/cm 3 . The dry generation method which was used for generating fungal spores has proved to be reproducible and easy to control, as well as simple and inexpensive. Crown
This article presents the results of the performance evaluation of the Ultraviolet Aerodynamic Particle Sizer (UVAPS, model 3312, TSI Inc., St. Paul, MN, USA), the novel instrument for real-time monitoring of biological aerosols. The main objective of the study was to compare the UVAPS response in measuring aerosols containing NADH, NADPH, or riboflavin particles. At the excitation and emission wavelengths at which the UVAPS operates, these compounds are the primary intrinsic fluorophores specific to biological particles. In addition, the study was focused on determining the detection limits of the UVAPS for these fluorophores. This information is important for the interpretation of UVAPS data while measuring bacterial aerosols. Fluorescence measurements were initially taken with a Varian Cary Eclipse Fluorescence Spectrophotometer for all three fluorophores. The samples were then aerosolized with the 6-jet Collison nebulizer. Riboflavin was found to be a stronger fluorophore than both NAD(P)H coenzymes. The fluorescence signals were considerably weaker for the NADPH samples compared to the NADH samples. The sensitivity of the UVAPS was found to be sufficiently high to detect the NADH and riboflavin at the concentrations characteristic of bacterial cells. The results of this study are discussed in a context of the results previously reported for the bacterial aerosols. It can be concluded that the amount of fluorophores detectable in uniformly mixed particles is equal to or less than the fluorophores expected to be present in the individual bacterial particles.
While various sampling methods exist for collecting and enumerating airborne bacteria and fungi, no credible methodology has yet been developed for airborne viruses. A new sampling method for monitoring the personal exposure to bioaerosol particles has recently been developed and evaluated with bacteria and fungi. In this method, bacterial/fungal aerosol is aspirated and transported through a porous medium, which is submerged into a liquid layer. As the air is split into numerous bubbles, the particles are scavenged by these bubbles and effectively removed. The current feasibility study was initiated to evaluate the efficiency of the new personal sampler prototype ("bubbler") with airborne viable viruses. Two common viral strains, Influenza (stress-sensitive) and Vaccinia (robust), were aerosolized in the test chamber and collected by two identical "bubblers" that operated simultaneously for a duration of upto 5 min. A virus maintenance liquid, proven to be the optimum collecting environment for the test organisms, was used as a collection fluid. After sampling, the collecting fluid was analyzed and the viral recovery rate was determined. The overall recovery (affected not only by the sampling but also by the aerosolization and the aerosol transport) was 20% for Influenza virus and 89% for Vaccinia virus. The new sampling method was found feasible for the collection and enumeration of robust airborne viruses. ᭧
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.