PubMed · 8747708
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
R A Etzel. 1995. Indoor air pollution.. https://doi.org/10.3928/0090-4481-19951201-09
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
BACKGROUND: Latency effects are an important factor in assessing the public health implications of an occupational or environmental exposure. Usually, however, latency results as described in the literature are insufficient to answer public health related questions. Alternative approaches to the analysis of latency effects are warranted. METHODS: A general statistical framework for modeling latency effects is described. We then propose bilinear and exponential decay latency models for analyzing latency effects as they have parameters that address questions of public health interest. Methods are described for fitting these models to cohort or case-control data; statistical inference is based on standard likelihood methods. APPLICATION: A latency analysis of radon exposure and lung cancer in the Colorado Plateau uranium miners cohort was performed. We first analyzed the entire cohort and found that the relative risk associated with exposure increases for about 8.5 years and thereafter decreases until it reaches background levels after about 34 years. The hypothesis that the relative risk remains at its peak level is strongly rejected (P < 0.001). Next, we investigated the variation in the latency effects over subsets of the cohort based on attained age, level and rate of exposure, and smoking. Age was the only factor for which effect modification was demonstrated (P = 0.014). We found that the decline in effect is much steeper at older ages (60+ years) than younger. CONCLUSION: The proposed methods can provide much more information about the exposure-disease latency effects than those generally used.
One of the immediate consequences of massive radioisotope release into the atmosphere is contamination of the biosphere. This contamination can affect plants either by direct deposition onto the leaves, or by contaminating the soil followed by absorption by the roots. Knowledge of the efficacy of the two routes of radionuclide incorporation into the food chain is fundamental to understanding the mechanisms by which radioactive contamination reaches man. The present work analyzes the incorporation of 134Cs and 85Sr via root and leaf uptake into the parts consumed by man, for two very different crops: turnip (Brassica napus) and broad bean (Vicia faba). The root uptake studies consider the available soil fraction for these two radionuclides, and indicate greater availability for 85Sr than for 134Cs which is fixed rapidly in the soil. For the study of leaf uptake, leaves were contaminated at three different stages of plant growth; the results indicate an inverse dependence of the transfer coefficients on the time elapsed from the moment of the contamination to harvesting of the edible parts.
GPS-indexed in-situ and car-borne survey of terrestrial gamma-ray dose rates were carried out in Brunei and adjacent areas using two portable NaI(Tl) counters. The mean and population weighted average dose rates for Brunei are 34 and 33 nGy/h, respectively. The car-borne data and the in-situ data when spectral analysed separately, were found to show fractal behaviour with D of 1.7 and 1.8, respectively. A contour map of the dose rates was also produced.