RESUMEN
OBJECTIVES: To assess the distribution of personal exposures to nitrogen dioxide (NO2) in school children, and to investigate factors that might influence personal exposure. METHODS: NO2 exposures were assessed by use of passive diffusion tubes for 46 children aged 9-11 years, selected from two Southampton schools. The tubes were worn for seven days, and parallel measurements were made with static samplers in the child's kitchen, living room, classroom, and playground. Information about potential exposures was collected by questionnaire. RESULTS: Personal exposures to NO2, averaged over seven days, ranged from 11 to 257 micrograms/m3 (6 to 137 ppb) with a geometric mean of 36 micrograms/m3 (19 ppb). Exposures correlated with concentrations of NO2 recorded in the home, but the relation was far from exact. Factors associated with increased personal exposure included the use of gas appliances in the home, living with one or more smokers, and travel to school by means other than a car. However, together these variables only explained a small part of the variation in personal exposures. CONCLUSIONS: These findings reinforce the need for personal monitoring of exposure in studies investigating potential health effects of NO2 in children.
Asunto(s)
Exposición a Riesgos Ambientales/análisis , Dióxido de Nitrógeno/análisis , Niño , Inglaterra , Monitoreo del Ambiente/métodos , HumanosRESUMEN
An investigation was undertaken to determine whether permanent damage to the central nervous system (CNS) is associated with transient decompression sickness in the goat. Twelve goats were compressed in air at 100 fsw for one hour. After decompression over a period of 2.5 min, seven animals showed signs of decompression sickness and four of these were treated by recompression in oxygen. Residual clinical signs after 12 h were present in one animal only. The seven affected goats were killed 48 h after decompression. Lesions in the CNS (other than hemorrhage) were confined to the spinal cord of three animals that had shown paralysis, and consisted of infarction of white matter with occasional microthrombi and perivascular proteinaceous edema of the gray matter. In all seven animals, there was hemorrhage in the spinal cord and in four, hemorrhage in the brain. Infarction of the spinal cord was not present in the four animals that had shown only slight clinical signs (limping); one of these goats had been treated by recompression in oxygen.