Concentration gradient patterns of aerosol particles near interstate highways in the Greater Cincinnati airshed.

The objective of this study was to determine if there is an exposure gradient in particulate matter concentrations for people living near interstate highways, and to determine how far from the highway the gradient extends. Air samples were collected in a residential area of Greater Cincinnati in the vicinity of two major highways. The measurements were conducted at different distances from the highways by using ultrafine particle counters (measurement range: 0.

Dynamic monitoring of the dust pickup efficiency of vacuum cleaners.

This study evaluated a new method that uses an optical aerosol photometer for dynamically monitoring dust pickup efficiency during vacuuming. In the first stage of this study the new method was compared with built-in dirt sensors installed by vacuum cleaner manufacturers. Through parallel testing it has been shown that the widely available built-in dirt sensors are not sensitive enough to register small (< 53 microm) dust particles.

Comparison of filter bag, cyclonic, and wet dust collection methods in vacuum cleaners.

In this study, methods were developed for comparative evaluation of three primary dust collection methods employed in vacuum cleaners: filter bag, cyclonic, and wet primary dust collection. The dry collectors were evaluated with KCl test aerosols that are commonly used in filter testing. However, these aerosols cannot be used for evaluating wet collectors due to their hygroscopicity.

Particle emission characteristics of filter-equipped vacuum cleaners.

Industrial vacuum cleaners with final high-efficiency particulate air (HEPA) filters traditionally have been used for cleanup operations in which all of the nozzle-entrained dust must be collected with high efficiency, for example, after lead-based paint abatement in homes. In this study household vacuum cleaners ranging from $70 to $650 and an industrial vacuum cleaner costing more than $1400 were evaluated relative to their collection efficiency immediately after installing new primary dust collectors in them. Using newly developed testing technology, some of the low-cost household vacuum cleaners equipped with a final HEPA filter were found to have initial overall filtration efficiencies comparable to those of industrial vacuum cleaners equipped with a final HEPA filter.

Test methods for evaluating the filtration and particulate emission characteristics of vacuum cleaners.

The overall filtration efficiency of a vacuum cleaner traditionally has been tested by placing the vacuum cleaner in a test chamber and measuring aerosol concentrations at the chamber inlet and outlet. The chamber test method was refined and validated in this study. However, this chamber test method shows an overall filtration efficiency of close to 100% for most of the industrial vacuum cleaners and for most of the newly developed household vacuum cleaners of midprice range or higher because all these vacuum cleaners have a high-efficiency particulate air (HEPA) or other highly efficient filter installed at the exhaust.