Toxicity index and the time taken to incapacitate mice under combustion gases of burning wooden materials

The purpose of this study was to investigate the toxicity of combustion gases from burning wooden materials. The toxicant index and mice exposure experiment were used to evaluate the toxicity index. The time taken to incapacitate mice under the impact of burning 19 solid wood species and 7 kinds of plywood were investigated. The results showed that the toxicity index of burning solid wood ranged from 1.5 to 2.5, and its main toxicant was CO₂. The toxicant index of burning plywood was higher, ranging from 3.0 to 6.0, and its main toxicity was NO_x. A good correlation was observed between the time taken to incapacitate mice (Xs) and the weight loss rate of burning solid wood. When the concentration of CO was higher than 1% in the exposure chamber, the mice stopped their activity within 2min. The time taken to incapacitate mice (Xs) and the minimum concentration of O₂ in the exposure chamber could be represented by a positive linear regression formula. The concentrations of O₂ and CO₂ exhibited a positive effect and the concentration of CO had a negative effect on the Xs values of mice.Part of this paper was presented at the 52nd Annual Meeting of the Japan Wood Research Society, Gifu, April 2002