Safety recommendations for moxa use based on the concentration of noxious substances produced during commercial indirect moxibustion

BACKGROUND: Moxibustion therapy has been used historically for thousands of years and there are many clinical trials supporting its efficacy and effectiveness for various conditions. Moxa smoke has been a major reason for avoiding moxibustion due to its smell and potential risks to the human body. METHODS: 10 units of commercial indirect moxa (CIM) from six manufacturers (A–F) were burnt in a 2.5×2.5×2.5 m chamber without ventilation, and concentrations of carbon oxides (CO and CO(2)), nitrogen oxides (NOx), and volatile organic compounds (VOCs) from the indoor air samples were measured. RESULTS: For brands A, B, C, D, E, and F, respectively, relative to baseline values, we observed an increase in CO (from 0.002 to 0.007, 0.006, 0.005, 0.006, 0.005, and 0.006 parts per billion (ppb)), NOx (from 0.009 to 0.051, 0.025, 0.015, 0.050, 0.019, and 0.020 ppb), and total VOCs (TVOC; from 48.06 to 288.83, 227.93, 140.82, 223.22, 260.15, and 161.35 μg/m(3)), while the concentration of CO(2) was not elevated. Each CIM brand demonstrated different VOC emission characteristics, which could be divided into three groups. On average, we estimated that 20 units of CIM or 2.41 g moxa floss would need to be combusted in order to exceed the safe levels set by Korean environmental law. This limit is likely to be greater in the case of a larger room or use of ventilation. CONCLUSIONS: Despite increased CO/NOx/VOC concentrations, overall levels remained within safe limits. These findings may help clinicians to maintain safe moxibustion treatment conditions to help keep both patients and clinicians safe from the pollutants generated by moxa combustion.