A toxicological investigation of the air quality in a moxibustion treatment room as measured through particulate concentration and oxidative capacity

Abstract

Background: Moxibustion is a traditional Chinese medicine (TCM) therapy in which mugwort (Artemisia vulgaris) floss is burned to warm and stimulate acupoints. The modality has been used traditionally for thousands of years. However, smoke-related safety issues have recently been of concern, and little is known about moxa smoke and air quality in the clinical moxibustion environment. Objective: To assess the air quality in a typical moxibustion treatment room using particulate matter (PM) concentration and DNA oxidative damage at PM10. Methods: The study was conducted in August and November to December, 2011, at a TCM clinic in Beijing, China, in a moxibustion treatment room. A moxa-free treatment room and the outdoor area adjacent to the clinic were used as controls. PM10 concentrations were monitored with a portable digital dust indicator. The oxidative capacity of whole and water-soluble fractions of PM10 were detected using plasmid DNA assay. The results were shown as TD40 values; that is, the amount of PM10 that causes plasmid DNA damage of 40%. Results: Average PM10 concentrations in the moxibustion room were 2.56 mg m−3 in summer and 2.78 mg m−3 in winter, much higher than at control sites. For whole and water-soluble fractional PM10, the average summer TD40 values collected in the moxibustion room were 791.67 μg ml−1 and 876.33 μg ml−1 respectively, and the winter values were 779.86 μg ml−1 and 879.57 μg ml−1. These results of winter samples were significantly higher (p < 0.001) than the corresponding results from control sites. However, there was no statistical difference (p = 0.06) between the TD40 values of both the whole and water−soluble fractional PM10 from the moxibustion treatment room, while differences were significant in the general treatment room (p = 0.025) and at the outdoor site (P < 0.001). Conclusion: Our study shows that moxa smoke increases PM10 concentration. However, the oxidative capacity of PM10 in the moxibustion room was much lower than that at control sites with the same particulate burden, and the bioactivity at that site was mainly from the watersoluble fraction, another difference from the controls. This unexpected bioactivity is assumed to relate to the low toxicity of moxa smoke or to its proven antioxidant activity. Overall, further research is needed.