Emission of ozone and organic volatiles from a selection of laser printers and photocopiers.

To estimate the impact of office equipment on the quality of indoor air, the emission of ozone and organic volatiles was measured from one photocopier and four laser printers, three of which operated according to traditional corona discharge technology. The laser printers equipped with traditional technology emitted significant amounts of ozone and formaldehyde. Lesser amounts of other volatile aldehydes were emitted during printing. The photocopier emitted mainly ozone. In a well-ventilated office environment, the amounts encountered here for individual volatiles were within recommended maximum exposure limits for a reasonable density of printers. Because it is not known whether the concentration of irritating volatiles, such as formaldehyde, should be kept lower in an ozone rich environment or not, and because emissions in the immediate vicinity of the printers exceeded recommendations, the authors recommend that laser printers equipped with the traditional corona rods not be placed beside or immediately at the working site of office personnel. This way, ozone concentrations can be kept below recommended maximum exposure limits, provided that the ventilation rate is adequate. Further, it seems that if a reliable quantitative comparison of total organic volatiles prior to and during printing is to be made, the inertness of the sorbent toward ozone should be confirmed.

Measurement and analysis of nicotine and other VOCs in indoor air as an indicator of passive smoking.

In Finland the Tobacco Act was amended in 1994 to include workplaces. The developed method for estimating passive smoking, or environmental tobacco smoke utilised the widely used measurement of volatile organic compounds in indoor air quality surveys. The method is based on active sorbent sampling, thermal desorption and gas chromatography/mass selective detection (GC/MS) analysis and it has been tested in a chamber and in field conditions. The method can be used simultaneously to measure volatile organic compounds and exposure to tobacco smoke. We recommend nicotine, collected by active sampling, as an indicator for the evaluation of the exposure to environmental tobacco smoke spreading from smoking areas.

Biological monitoring of exposure to benzene in the production of benzene and in a cokery.

The purpose of this study was to compare different biological methods in current use to assess benzene exposure. The methods involved in the study were: benzene in blood, urine and exhaled air, and the urinary metabolites t,t-muconic acid (MA) and S-phenylmercapturic acid (S-PMA). Blood, urine and exhaled air samples were collected from workers in a benzene plant (pure benzene exposure) and cokery (mixed exposure, e.g. polycyclic aromatic hydrocarbons--PAHs) in an Estonian shale oil petrochemical plant. The benzene in these samples was analysed with a head-space gas chromatograph, and the metabolites MA and S-PMA with a liquid chromatograph using methods developed from published procedures. Some of the values measured in the Estonian shale oil area were high in comparison with those published during the last few years, whereas the values measured in the control group did not show any exposure to benzene except in the smokers group. The highest median exposure was in the benzene factory, 0.9 cm3/m3 TWA (2.9 mg/m3) and the highest individual value was 15 cm3/m3 TWA (49 mg/m3). All biological measurements in this study gave the same assessment about exposure to benzene and correlated highly significantly with each other and with the air measurements (r = 0.8 or more). In the benzene factory the correlation was good even when calculated from samples with air concentration < 1 cm3/m3 (3.2 mg/m3) in the case of blood benzene and urinary MA. However, for S-PMA it was weak (r = 0.4) and for benzene in urine and exhaled air it did not exist any more. In the cokery, with mixed exposure, the correlation at low levels was weaker even for blood benzene and urinary MA (r = 0.6). According to the results in the benzene factory the exposure to pure benzene at the level 1 cm3/m3 (3.25 mg/m3) TWA gave: the blood benzene value about 110 nmol/l (8.6 micrograms/l), MA 23 mumol/l (3.3 micrograms/l) or 2.0 mg/g creatinine, S-PMA 58 micrograms/g creatinine or 0.4 mumol/l (95.7 micrograms/l), benzene in urine 499 nmol/l (39 micrograms/l), and benzene in the exhaled air 2.8 nmol/l (0.2 microgram/l). In general, the measurement of benzene in blood and in exhaled air, as well as benzene and its metabolites MA and S-PMA in urine, all gave similar results. However, at low exposure level (< 1 cm3/m3) the most reliable analyses were MA in urine and benzene in blood.