Characterization of the aerosol release from spray cleaning and disinfection products - Spray scenarios in a climate chamber.

Cleaning work using spray products has been associated with adverse respiratory effects but little is known of the exposure concentrations. The purpose of this study was to characterize aerosol generation at spray scenarios in a controlled climate chamber. Spraying on vertically and horizontally oriented surfaces, as well as spraying on a cloth, was investigated. Furthermore, the effect of nozzle geometry was tested. The average mass generation rates of six pressurized spray cans and 13 trigger sprays were about 1.7 g/s and did not differ significantly, but the average values of the individual sprays had large variations (0.5-3.1 g/s). The time required to halve the air concentration of aerosol particles, the half-life time, was determined for all spray products. The average half-life time of the total particle mass concentration (TPMC) of the pressurized spray cans was 0.5 h versus 0.25 h for trigger sprays. Gravimetrically determined airborne fractions of pressurized spray cans tended to be higher than those of trigger sprays. However, airborne fractions based on the measured peak TPMC were up to three orders of magnitude smaller. A comparison of different trigger spray nozzles when spraying the same product showed that the TPMC can be up to 18 times higher for the largest emitting nozzle. The distance of the nozzle to a cloth should be 1 cm to significantly reduce the concentration of the generated aerosols. ConsExpo modeling predicted the measured peak TPMC well but less well the decay.

Historical Asbestos Measurements in Denmark-A National Database.

OBJECTIVES: Due to the long lag-time for health outcomes, historical asbestos exposure measurements are valuable to support assessments of associated occupational health effects, and also to assess time trends and effects of preventive measures. METHODS: Different sources of stored data were collated, assessed and refined to create a harmonized database on historical asbestos fibre concentrations measured in specific work tasks and different industries. The final database contains 9236 asbestos measurements from Danish workplaces collected from 1971 to 1997. RESULTS: The geometric mean of asbestos concentrations in different occupations and tasks ranged from 0.003 to 35 fibres cm-3. Highest concentrations were registered during handling of asbestos products in the construction services during the period 1981-1997. Although all the measured asbestos exposures without the use of respiratory equipment by the worker in the period of 1971-1997 exceeded the current 8-h time-weighted average exposure limit of 0.1 fibres cm-3, the majority of samples collected in the earlier period of 1971 to 1980 did not exceed the exposure limit of 2 fibres cm-3, which was in place at the time. All exposure data obtained from 1980 and onwards were found to be one seventh of the mean fibre concentrations in the previous measurement period. The impact of time shows a clear exponentially decreasing trend-line. CONCLUSIONS: Despite limitations in coverage of different occupations and tasks associated with the inventoried historical asbestos measurements, the data are helpful to identify specific work scenarios within an industry, where relatively high asbestos exposure levels may still occur or have occurred from 1971 to 1997.