The removal efficiency of high efficiency air filters against microbe-carrying particles (MCPs) in the air supply of occupied rooms, such as cleanrooms, was determined. Knowing the size distribution of MCPs in the air to be filtered, and the removal efficiency of a filter against individual particle diameters, the overall removal efficiency was ascertained. A variety of filters were investigate...

A fundamental problem with measurements of alpha activity on air filters from the nuclear workplace is that the calibration sources used with radioactivity-in-air monitors are not in the same physical form as actual samples. The samples suffer from alpha absorption due to effects such as self-attenuation within the radioactive particle, entrapment of the particle within the filter, and the accu...

The Ames assays strains TA98 and TA100 have been useful in characterizing complex mixtures from organic solvent extracts of particles from diesel-powered vehicles, ambient air, and other sources. In this paper we report preliminary experiments using TA102, a bacterial strain that detects compounds that can oxidize DNA, to characterize the mutagenicity of an ambient air sample collected in Ann A...

Higher-efficiency HVAC filters generally have a higher pressure drop and are widely assumed to increase energy consumption in smaller air conditioning systems. To explore the effects of filters in real buildings, we monitored 17 residential and light-commercial forced air cooling systems in Austin, TX. Measurements were made once per month for one year at each site with filters from three diffe...

The goal of this study was to investigate the effectiveness of stand-alone modular air purification systems in improving air quality in dental practices, hospital and laboratory environments. As air pollutant make-up and concentration may vary significantly in different indoor environments, the air cleaning technologies utilised should be optimised for the pollutants targeted in a particular en...

The air in hospital wards with patients at high risk (Surgeries, Intensive Care Units and Bone Marrow Transplant Centers) has been surveyed less than the one in Operating Rooms. Therefore in this study we considered useful to verify the microbic contamination of the air of those wards evaluating the consistency of ventilation systems in relation also to the presence and location of HEPA absolut...

conclusions the mssrhs could be considered as a more suitable packing material for long-term biofilter operation to remove h2s pollution. results in this study, after 53 days of operating time and 54 g/m3h mass loading, the ph values in the ss and mssrhs packed filters were reduced from 6.8 to 1.8 and from 6.9 to 3.4, respectively. the mssrhs packed filter showed more buffering capacity to resi...

METHODS. This was a randomized, controlled trial in which the children were assigned to 1 of 2 groups. For 12 months, 1 group was exposed to HEPA air cleaners that were placed in the living room and bedroom, and the other group was exposed to paper sham filters. Filters were on for 50% of the time. Pulmonary function testing and cold-air challenges were performed at baseline, 6 months, and 12 m...

INTRODUCTION In March 2010, more than 213 countries worldwide reported laboratory confirmed cases of influenza H1N1 infections with at least 16,813 deaths. In some countries, roughly 10 to 30% of the hospitalized patients were admitted to the ICU and up to 70% of those required mechanical ventilation. The question now arises whether breathing system filters can prevent virus particles from an i...

Micropore filters are used during extracorporeal circulation to prevent gaseous and solid particles from entering the patient's systemic circulation. Although these devices improve patient safety, limitations in current designs have prompted the development of a new concept in micropore filtration. A prototype of the new design was made using 40-μm filter screens and compared against four comme...