Pm2.5 and ash residue from combustion of moxa floss

Abstract

Background Moxibustion, a Traditional Chinese Medicine technique, involves burning moxa floss to apply heat to certain points or areas of the body surface to treat disease. Moxibustion releases a considerable amount of smoke into the environment. There remains controversy over the safety of moxa smoke and its potential effects on human health. Methods We measured the PM2.5 (particulate matter with aerodynamic diameter <2.5 μm) mass concentration in moxa smoke and the oxidative capacity of PM2.5 and moxa ash (using a plasmid scission assay in whole and water-soluble fractions) in the by-products of moxibustion produced from burning moxa floss of different ratios (3:1 or 15:1) and duration of storage (3 or 10 years) in three simulated moxibustion clinics. Results PM2.5 mass concentration was 224.28, 226.39  and 210.56 μg/m3 for samples A (3 years and 3:1 ratio), B (3 years and 15:1 ratio), and C (10 years and 3:1 ratio), respectively. Average D500 oxidative damage of PM2.5 was 29.42%, 29.16% and 27.01% and that of moxa ash was 22.78%, 20.60% and 21.42% for samples A, B and C, respectively. PM2.5 demonstrated a significantly greater oxidative capacity than moxa ash (p<0.05). Conclusions The oxidative DNA damage induced by individual PM2.5 following moxibustion was lower than that reported in other environments. However, PM2.5 mass concentration after moxibustion is still relatively high. We would recommend ensuring adequate ventilation during moxibustion to reduce any possible risks. Further studies are needed to better define the potential impact of particles in moxibustion by-products on human health.