The authors followed occurrence and formation of the national hygienic regulation of chemicals in workplace air, since 1920s in historical aspect. Now there is 90th anniversary of the regulation.
Quantitative analysis of threshold limit levels of UV-irradiation in the workroom environment established in USA, Netherlands and Russia was made. Comparison of its results with modern information about effective doses and action spectra of UV-radiation biological action allowed to reveal essential differences in the approach to rate setting and in some cases presence of internal contradictions and exceeding of threshold limit levels of UV irradiation above biologically effective values. The possibility of workroom UV standards utilisation for regulation of nature UV-radiation exposures was considered.
It will be clear from the aforegoing that occupational standards have varied over the past 30-40 years since the beginnings of the nuclear industry. Our perception of risk rates for cancer mortality and genetic effects has changed, such that the rates have been constantly revised upwards. Logically, dose limits should have been reduced in proportion, but this assumes a constant approach to the "tolerability" or "acceptability" of risk and this has not been demonstrated. Dose limits are not seen by management in the nuclear industry as the only plank in the structure of radiation protection; emphasis is also being given to the "optimization" ethic. In these circumstances a good test of the efficacy of the system of radiation control in limiting health effects is needed. As can be seen, no such study is available and, given the doses received and the numbers of workers involved, it is unlikely that any epidemiologic study, apart from studies on miners, will have sufficient statistical power to be totally unequivocal. However, some studies have shown cancer mortality associations with radiation exposure that are significant. Probably the best way to mitigate the inherent drawbacks in these studies is to pool data-sets, and this is being done. Other improvements will include estimates of cancer incidence in countries with cancer registries (e.g., U.K., Canada, and Sweden) and to perhaps go beyond epidemiologic data to consider sensitive biologic markers as indices of exposure. Overall the conclusion must be that the radiation industry cannot be complacent and for some tasks in the processes involved (e.g., uranium mining) there is strong evidence of a history of unacceptable health effects occurring.
OBJECTIVE: The principal aim of the study was to estimate the level of exposure to organic solvents of graffiti removers, and to identify the chemicals used in different cleaning agents. A secondary objective was to inform about the toxicity of various products and to optimise working procedures. METHODS: Exposure to organic solvents was determined by active air sampling and biological monitoring among 38 graffiti removers during an 8-h work shift in the Stockholm underground system. The air samples and biological samples were analysed by gas chromatography. Exposure to organic solvents was also assessed by a questionnaire and interviews. RESULTS: Solvents identified were N-methylpyrrolidone (NMP), dipropylene glycol monomethyl ether (DPGME), propylene glycol monomethyl ether (PGME), diethylene glycol monoethyl ether (DEGEE), toluene, xylene, pseudocumene, hemimellitine, mesitylene, ethylbenzene, limonene, nonane, decane, undecane, hexandecane and gamma-butyrolactone. The 8-h average exposures [time-weighted average (TWA)] were below 20% of the Swedish permissible exposure limit value (PEL) for all solvents identified. In poorly ventilated spaces, e.g. in elevators etc., the short-term exposures exceeded occasionally the Swedish short-term exposure limit values (STEL). The blood and urine concentrations of NMP and its metabolites were low. Glycol ethers and their metabolites (2-methoxypropionic acid (MPA), ethoxy acetic acid (EAA), butoxy acetic acid (BAA), and 2-(2-methoxyethoxy) acetic acid (MEAA)) were found in low concentrations in urine. There were significant correlation between the concentrations of NMP in air and levels of NMP and its metabolites in blood and urine. The use of personal protective equipment, i.e. gloves and respirators, was generally high. CONCLUSIONS: Many different cleaning agents were used. The average exposure to solvents was low, but some working tasks included relatively high short-term exposure. To prevent adverse health effects, it is important to inform workers about the health risks and to restrict the use of the most toxic chemicals. Furthermore, it is important to develop good working procedures and to encourage the use of personal protection equipment.
Over 90% of 91 day care centers in greater Montréal, Québec exceeded 1000 ppm of CO2 during January through April 1989. Four variables were independent positive predictors of CO2 levels: the density of children in the center; presence of electric heating; absence of a ventilation system; and building age. High levels of CO2 are associated with respiratory tract and other symptoms. Clear standards and inspection policies should be established for day care center air quality.
Notes
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