Design of a small personal air monitor and its application in aircraft

A small air sampling system using standard air filter sampling technology has been used to monitor the air in aircraft. The device is a small ABS constructed cylinder 5 cm in diameter and 9 cm tall and can be operated by non technical individuals at an instant notice. It is completely self contained with a 4 AAA cell power supply, DC motor, a centrifugal fan, and accommodates standard 37 mm filters and backup pads. The monitor is totally enclosed and pre assembled in the laboratory. A 45 degrees twist of the cap switches on the motor and simultaneously opens up the intake ports and exhaust ports allowing air to pass through the filter. A reverse 45 degrees twist of the cap switches off the motor and closes all intake and exhaust ports, completely enclosing the filter. The whole monitor is returned to the laboratory by standard mail for analysis and reassembly for future use. The sampler has been tested for electromagnetic interference and has been approved for use in aircraft during all phases of flight. A set of samples taken by a BAe-146-300 crew member during two flights in the same aircraft and analyzed by GC-MS, indicated exposure to tricresyl phosphate (TCP) levels ranging from 31 to 83 nanograms/m(3) (detection limit <4.5 nanograms/m(3)). The latter elevated level was associated with the use of the auxiliary power unit (APU) in the aircraft. It was concluded that the air sampler was capable of monitoring air concentrations of TCP isomers in aircraft above 4.5 nanogram/m(3).

Effects of theatrical smokes and fogs on respiratory health in the entertainment industry

BACKGROUND

Theatrical fogs (glycol or mineral oil aerosols) are widely used in the entertainment industry to create special effects and make lighting visible.

METHODS

We studied 101 employees at 19 sites using fogs and measured personal fog exposures, across work shift lung function, and acute and chronic symptoms. Results were also compared to an external control population, studied previously.

RESULTS

Chronic work-related wheezing and chest tightness were significantly associated with increased cumulative exposure to fogs (mineral oil and glycols) over the previous 2 years. Acute cough and dry throat were associated with acute exposure to glycol-based fogs; increased acute upper airway symptoms were associated with increased fog aerosol overall. Lung function was significantly lower among those working closest to the fog source.

CONCLUSIONS

Mineral oil- and glycol-based fogs are associated with acute and chronic adverse effects on respiratory health among employees. Reducing exposure, through controls, substitution, and elimination where possible, is likely to reduce these effects.

Exposures to atmospheric effects in the entertainment industry

Theatrical fogs are commonly used in the entertainment industry to create special atmospheric effects during filming and live productions. We examined exposures to mineral oil-and glycol-based theatrical fogs to determine what fluids and effects were commonly used, to measure the size distributions of the aerosols, and to identify factors associated with personal exposure levels. In nonperformance jobs in a range of production types (television, film, live theater, and concerts),we measured airborne concentrations of inhalable aerosol,aldehydes, and polycyclic aromatic hydrocarbons, and collected observations about the sites and tasks performed. Both mineral oil and glycols were observed in use on about one-half the production days in the study. The most common effect produced was a generalized haze over the entire set. Mean personal inhalable aerosol concentrations were 0.70 mg/m3(range 0.02 to 4.1). The mean proportion of total aerosol mass less than 3.5 microns in aerodynamic diameter was 61%. Exposures were higher when mineral oils, rather than glycols, were used to generate fogs. Higher exposures were also associated with movie and television productions, with using more than one fog machine, with increased time spent in visible fog, and for those employed as "grips." Decreased exposures were associated with increasing room temperature, with increasing distance from fog machines, and for those employed as "sound technicians." Exposures to theatrical fogs are just beginning to be measured. It is important to consider these exposures in light of any health effects observed, since existing occupational exposure limits were developed in other industries where the aerosol composition differs from that of theatrical fogs.

Evaluation and determinants of airborne bacterial concentrations in school classrooms

A survey of 39 elementary schools was undertaken to determine indoor air concentrations of bioaerosols within a coastal, temperate climatic zone in British Columbia, Canada. This article reports the results for airborne bacteria. Determinants of exposure were grouped into environmental (outdoor temperature, relative humidity, season, weather), ventilation and comfort parameter (indoor relative humidity, temperature, indoor CO2 concentration, indoor fungal concentration), and occupancy (number of occupants, activity levels, occupancy patterns) variables. Regression modeling was used to evaluate the association between these factors and measured concentrations of indoor mesophilic bacteria. Naturally ventilated rooms (47% of the total rooms surveyed) had higher bacterial counts than mechanically ventilated rooms (geometric mean 325 vs. 166 CFU/m3, respectively, p < 0.001). In univariate analyses, bacterial counts were negatively correlated with supply and exhaust flow rates, air exchange rates, and the percentage of the day that occupants spent quietly sitting at their desks. Analysis of bacterial groups indicated various sources of the bacterial aerosol, with micrococci and staphylococci closely associated with occupancy variables, Bacillus with site and occupancy, and coryneform bacteria with site variables only. Approximately 60% of the variance in the outcome measurement of total bacteria was accountedfor by indoor CO2, lower air exchange rate, the age of the building, signs of current or old moisture stains, room volume, indoor relative humidity, and occupant activity level in a multiple linear regression model, with ventilation factors accounting for 40% of the variance.