Sensory irritation evoked by the thermal decomposition products of plasticized poly(vinyl chloride)

Abstract

AbstractA decrease in respiratory rate in mice during exposure to irritating airborne chemicals has been utilized as a response parameter to characterize the degree of upper respiratory tract irritation (sensory irritation) to the thermal decomposition products of plasticized poly(vinyl chloride). The plasticized poly(vinyl chloride) was placed in a low mass vertical furnace and thermally decomposed in an air atmosphere at a programmed heating rate of 20°C min−1. The thermogravimetric study of the plasticized poly(vinyl chloride) demonstrated that two distinct weight loss fractions occurred during the decomposition process. Groups of four male swiss‐webster mice were exposed to the thermal decomposition products of the first weight loss fraction in the range 0.03–0.77 mg l−1 and to the second weight loss fraction in the range 0.03–0.38 mg l−1. Dose‐response curves were plotted by utilizing the maximum percent decrease in respiratory rate during each exposure as the response parameter. Comparison of these curves to a dose‐response curve for hydrogen chloride showed that both the first and second weight loss fraction of plasticized poly(vinyl chloride) were more potent than hydrogen chloride in terms of sensory irritation. From these dose‐response relationships qualitative and quantitative predictions of human responses to the thermal decomposition products of plasticized.