Does the burning of moxa (Artemisia vulgaris) in traditional Chinese medicine constitute a health hazard?

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1 1 Seretary, British Aupunture Counil (BAC), London, UK; 2 Member of BAC exeutive ommittee and safe pratie ommittee, London, UK; 3 Member of BAC exeutive ommittee and hair of safe pratie ommittee, London, UK Correspondene to: Mr J Wheeler, Seretary, British Aupunture Counil, 63 Jeddo Road, London W12 9HQ, UK; john@aupunture.org.uk Does the burning of moxa (Artemisia vulgaris) in traditional Chinese mediine onstitute a health hazard? John Wheeler, 1 Belinda Coppok, 2 Ceil Chen 3 ABSTRACT Bakground: Conerns have been expressed about potential toxiity of the smoke produed by the burning of moxa in traditional Chinese mediine. With the advent of strit anti-smoking legislation in the UK, it was deided to test the volatiles produed by moxibustion and ompare them with urrent agreed safe exposure levels. Method: Moxa, in the form of igar shaped moxa stiks or rolls, was tested under International Organization for Standardization onditions in a tobao testing laboratory, and the quantities of a number of predetermined volatiles measured. The smoke tested was sidestream smoke, the smoke whih arises from the burning tip of the moxa. The test results were then saled up to reflet normal use and to provide diret omparisons with agreed national safety standards for both short- and long-term exposure levels. Results: Levels of only two volatiles produed were equivalent or greater than the safe exposure levels, as was the arbon monoxide level reported, both as a onsequene of using worst ase assumptions for omparison. Under normal operating onditions neither volatile nor arbon monoxide would present a safety hazard. One group of hemials tested, the aromati amines, with known arinogeni properties have no agreed safety levels. Results for these in the study ompared favourably with bakground levels reported in urban environments. Conlusion: There are no immediate onerns arising from the ontinued use of moxa as a therapeuti modality in traditional Chinese mediine. Further testing may be required to establish whether urrent reommendations for ventilation and leansing of treatment room surfaes may need to be revised. Stronger reommendations may also be neessary on the inadvisability of using moxa on broken skin. The introdution of new igarette smoking legislation in the UK has raised safety onerns about the smoke generated by other, mainly non-industrial, proesses. Industrial proesses are relatively tightly ontrolled, with emissions subjet to learly defined safe or permissible oupational exposure limits suh as those outlined in the UK Health and Safety Exeutive s publiation EH40 Oupational exposure limits The same testing has not usually extended to soial smoke produts. However, although the legislation was primarily aimed at tobao smoking, usually defined as the transitive at of smoking a tobao or tobaosubstitute produt, questions have been raised about hurh inense and other soial or nonindustrial smoke-generating ativities. The British Aupunture Counil (BAC) has been aware from patient feedbak that some members of the publi are onerned about the levels of smoke produed by the burning of moxa, a Chinese herb (Artemisia vulgaris) similar to mugwort. This is extensively used in Chinese mediine, where it is applied diretly onto the skin, heaped on speial needles or passed in igar-shaped stik form over the skin. The burning of moxa generates heat whih is used as a form of treatment. Although other heat devies are oasionally substituted (for example, infrared devies), moxa is widely believed within Chinese mediine to have speifi energeti harateristis whih make its use preferable. With over pratitioners in the UK potentially using moxa on a regular basis, it was onsidered important to establish what byproduts arose from its use and whether these fell within safe exposure limits. There is no urrently available evidene to suggest that there are adverse effets from moxa smoke. Anedotal evidene exists that pratitioners and patients with respiratory disorders find its use problemati, but there is nothing to suggest that this is from the unique harateristis of moxa over and above the prodution of smoke as an irritant. Evidene does exist from several Japanese studies that moxa has possible ytotoxi effets. 1 4 The benhmark levels for igarette smoke ingredients were established by the use of standard equipment and protools. It was deided to submit moxa to the idential testing regime at a laboratory whih met these standards. Cigarette smoking generates two kinds of smoke: mainstream smoke and sidestream smoke. Mainstream smoke desribes the smoke inhaled and then exhaled by the smoker, sidestream smoke is smoke generated at the burning tip of the igarette in between puffs or while resting in an ashtray. An initial trial run established that testing mainstream smoke was not possible, sine the moxa was paked too tightly within the roll to allow suffiient smoke to permeate the length of the stik for testing purposes. This sampling was also rejeted on the grounds that moxa is never inhaled in this way. However, it did establish that only minute quantities of smoke were lost by being absorbed or filtered within the stik. The groups seleted for testing were the most ommonly found volatile organi ompounds routinely assessed in igarette analyses and/or hemials: Tar Tar, niotine, arbon monoxide Polyyli aromati hydroarbons Benzo[a]pyrene, benzo[a]anthraene Aupunt Med: first published as /aim on 1 Marh Downloaded from on 8 Otober 2018 by guest. Proteted by opyright. 16 Aupunt Med 2009;27: doi: /aim

2 Ammonia Hydrogen yanide Poly aromati amines 1 & 2-Aminonaphthalene, and 3 & 4-aminobiphenyl Volatile organi ompounds 1,3-Butadiene, benzene, arylonitrile, toluene and styrene Semi volatile ompounds Pyridine and quinoline Phenols Catehol, phenol, hydroquinone, resorinol o- and m- & p-resol Carbonyls Formaldehyde, aetaldehyde, aetone, arolein propionaldehyde, rotonaldehyde, butyraldehyde and methyl ethyl ketone. There are a number of other hemials and ompounds assessed in igarette testing suh as the oxides of nitrogen, nitrosamines and metals suh as merury, nikel, lead, admium, hromium, arseni and selenium. At this stage, however, it was deided to restrit the testing to those groups whih represent the greatest known arinogeni risk in igarette smoke. 5 6 In the UK there are two types of oupational exposure limits set by the Health and Safety Exeutive s (HSE) regulations: maximum exposure limits () and oupational exposure standards. The main differene between the two limits is that an oupational exposure standard is set at a level at whih there is no indiation of a risk to health whereas for an, a residual risk may exist and the level set takes soio-eonomi fators into aount. Exposure limits of both kinds are set as the result of deliberation of expert ommittees and publi onsultation. s were hosen as the basis for omparison with the test results beause most of the analytes for whih the tests were onduted fall within this ategory by virtue of their potential toxiity. For the purposes of analysing the signifiane of the results obtained from the testing of moxa, it was deided to use the s from table 1 of the Health and Safety Exeutive s publiation EH40 Oupational exposure limits Where there was no relevant information from the UK publiation use was made of the USA Oupational Health and Safety Administration s (OSHA) permissible exposure limits (PEL) data, Standard Z-1 limits for air ontaminants. Other soures were identified and used. These inluded the Amerian Congress of Government Industrial Hygienists, the US National Institute for Oupational Safety and Health and the Amerian Industrial Hygiene Assoiation. Where a non-regulatory limit has been applied this usually means that the regulatory body has not yet set a limit, not that it does not regard a limit as neessary. METHOD Moxa is used in many different forms and with many other ingredients added to the basi material. It was important to selet a form whih would generate lear results. Only pure moxa was used; moxa prodution remains a ottage industry in China, and many varieties are adulterated, either intentionally or aidentally, with other herbal produts. Of the pure forms available, it was deided to use the stik form or moxa roll. This is a tightly rolled ylinder of moxa with a paper asing, the size and shape of whih were ompatible with the standard igar testing equipment. The brand seleted, atalogue referene MX-09 from Oxford Medial Supplies in California, was hosen speifially beause the paper oating had no ink printing, so there would be no hydroarbon residues from the inks to skew the results. Certifiates of authentiity were sought and reeived from the manufaturer in China whih established that the produt was 100% pure wild grown Folium Artemisiae Argyi with no hemial treatments used in its proessing. The sidestream smoke was generated under onditions speified by the International Organization for Standardization smoking regime for igars. The moxa roll was held in horizontal position in a smoking mahine port and the sidestream smoke generated by burning the stik for five minutes was olleted on a 44 mm Cambridge filter pad using a fish-tail himney mounted above the burning stik end. Eah test was repeated three times. The tests for eah of the groups of volatiles listed above required speifi variations on this general proedure. Eah is outlined in the full laboratory report available on the British Aupunture Counil website ( In order to draw omparison with, it was deided to adjust the results as follows: (a) Short-term exposure limits are usually alulated in mg/ m 3 per 15 minute exposure. It was deided to allow for the unlikely irumstane that the patient and pratitioner oupied a ube with 1.5 m sides (3.375 m 3 ) into whih moxa was burned without any ventilation or diffusion of smoking by-produts. Aordingly, the figures from the laboratory reports for ompounds generated by moxa burned in one minute were saled up to produe a diret omparison with agreed s and PELs. (b) Long-term exposure limits, generally referred to as a timeweighted average, are also usually expressed in mg/m 3. Again, it was deided to make an assumption of a signifiant but possible ase of the burning of moxa for 15 minutes per hour in an eight hour day in an average-size treatment room of 3m62.5 m62 m, or 15m 3, with equal diffusion throughout the day and no effetive means of ventilation. The figures have also in some ases been re-alulated and shown in parts per million (ppm) for omparisons, where the safety data are only available in this form. The data were assembled primarily from the HSE and OSHA douments mentioned previously, but also made use of other industry soures in whih limits were variously expressed in mg/m 3 and ppm. The other soure most frequently ited was the Amerian Congress of Government Industrial Hygienists but there are also figures from the US National Institute for Oupational Safety and Health and the Amerian Industrial Hygiene Assoiation. Tables 1 and 2 show the soure for eah figure /PEL quoted in both short- and long-term exposure limits, respetively. RESULTS Tables 1 and 2 show the results produed for the duration of the International Standards Organisation test yle in the form of quantities of analyte generated per minute, and then show omparisons with existing oupational exposure limits and permissible exposure limits. Even with onentrations of an order of magnitude greater than would normally be ahieved with normal dispersal and ventilation, few of the analytes reahed levels at whih there would be signifiant onerns. Table 3 shows a omparison between the amounts of aromati amines generated by the tests and figures from the Tobao Manufaturers Assoiation UK Benhmark Report Study 2003: Smoke onstituents study annex part 12. This study shows the amounts of the same four aromati amines produed by burning a igarette. The Tobao Manufaturers Assoiation tests were based on average weights per igarette of between 0.6 Aupunt Med: first published as /aim on 1 Marh Downloaded from on 8 Otober 2018 by guest. Proteted by opyright. 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3 Table 1 A omparison of moxa smoke onstituents with short-term oupational exposure limits set by the HSE and OHSA Short term exposure Constituent Measure Test results amount and 0.8 mg oven dry weight of tobao. This ontrasts with the amount of weight lost through ombustion of moxa over a fiveminute period reported at 663 mg. DISCUSSION Of the various groups of volatiles tested, only two (arolein and hydroquinone) generated results whih exeeded the urrent long-term set by the HSE (although test results for hydroquinone fall within the set by OSHA, whih is four times greater than the HSE level). Given that the test figures were extrapolated to levels of onentrations unlikely to be found with normal rates of dispersal and diffusion in a treatment setting, the results were not onsidered to be signifiant. The same may be stated for the arbon monoxide figures whih are over 12 times higher for s (420 mg/m 3 against 35 mg/m 3 ) for long-term exposure. As well as the unlikely high extrapolations used for omparison, it is also suspeted that the testing method, whih allows the moxa stik to smoulder without movement, might well have aused mg/m 3 /15 mins per m 3 ppm Soure Short term mg/m 3 Tar mg/min 11.6 Carbon monoxide mg/min HSE Carbonyls Formaldehyde mg/min HSE Aetaldehyde mg/min HSE Aetone mg/min HSE Arolein mg/min HSE Propionaldehyde mg/min Crotonaldehyde mg/min Methylethylketone mg/min HSE Butyraldehyde mg/min Phenolis Hydroquinone mg/min Resorinol mg/min ND HSE Catehol mg/min Phenol mg/min mp-cresol mg/min o-cresol mg/min Volatiles 1,3-Butadiene mg/min HSE Isoprene mg/min Arylonitrile mg/min OSHA 10 Benzene mg/min OSHA 5 Toluene mg/min HSE Styrene mg/min HSE Semivolatiles Pyridine mg/min HSE Quinoline mg/min not established Ammonia mg/min HSE Poly aromati hydroarbons Benzo(a)anthraene ng/min Benzo(a)pyrene ng/min Hydrogen yanide mg/min HSE Aromati amines 1-Naphthyl Amine ng/min Naphthyl Amine ng/min Amino Biphenyl ng/min Amino Biphenyl ng/min HSE, Health and Safety Exeutive (UK);, maximum exposure limits; OHSA, Oupational Health and Safety Administration (USA); ppm, parts per million Short term ppm inomplete ombustion around the tip produing more arbon monoxide than arbon dioxide. However, sine the onentrations would ertainly fall below the with normal dispersal and ventilation, this was not onsidered worthy of further examination. The one group of hemials of potential onern are the aromati amines. The test results show these only to have been present at minute levels, but there are no agreed safety limits for any of the four analytes. These all appear on the OSHA s list of 13 known arinogens, OSHA Standard No , for whih the only urrent reommendations are that exposure should be maintained at the lowest possible levels. Their use in industrial proesses has been largely superseded by the use of alternatives, there being a strongly suggested ausal onnetion between aromati amines and bladder aner. 8 However, two studies undertaken in Italy appear to show that the levels of aromati amines in indoor air and outdoor air are signifiantly higher than the levels reorded in our testing of moxa. Lueri et al found that a group of 16 suh hemials Aupunt Med: first published as /aim on 1 Marh Downloaded from on 8 Otober 2018 by guest. Proteted by opyright. 18 Aupunt Med 2009;27: doi: /aim

4 Table 2 A omparison of moxa smoke onstituents with long-term oupational exposure limits set by the HSE and OSHA Long term exposure Constituent Measure Test results amount appeared at levels of between and ng per igarette in sidestream smoke, and were present at signifiant levels in rooms adjaent to where smoke had first been produed. 9 Palmiotto et al demonstrated that for a range of ten aromati amines levels of 3 ng/m 3 (in Siena) and 104 ng/m 3 (Brindisi) mg/m 3 /TWA 8615 min rolls/15 m 3 ppm Soure long term mg/m 3 Tar mg/min 11.6 Carbon monoxide mg/min HSE Carbonyls Formaldehyde mg/min HSE Aetaldehyde mg/min HSE Aetone mg/min HSE Arolein mg/min HSE Propionaldehyde mg/min ACGIH 20 Crotonaldehyde mg/min OSHA 6 2 Methylethylketone mg/min HSE Butyraldehyde mg/min AIHA 25 Phenolis Hydroquinone mg/min HSE 0.5 Resorinol mg/min ND HSE Catehol mg/min NIOSH 20 5 Phenol mg/min HSE 2 mp-cresol mg/min OSHA 22 5 o-cresol mg/min OSHA 22 5 Volatiles 1,3-Butadiene mg/min OSHA 2 1 Isoprene mg/min ACGIH ArylonItrile mg/min HSE Benzene mg/min HSE 1 Toluene mg/min HSE Styrene mg/min HSE Semivolatiles Pyridine mg/min HSE 16 5 Quinoline mg/min not established Ammonia mg/min Poly aromati hydroarbons Benzo(a)anthraene ng/min OSHA 0.2 Benzo(a)pyrene ng/min OSHA 0.2 Hydrogen yanide mg/min OSHA Aromati amines 1-Naphthyl Amine ng/min Naphthyl Amine ng/min Amino Biphenyl ng/min Amino Biphenyl ng/min long term ppm ACGIH, Amerian Congress of Government Industrial Hygienists; AIHA, Amerian Industrial Hygiene Assoiation; HSE, Health and Safety Exeutive (UK);, maximum exposure limits; NIOSH, National Institute for Oupational Safety and Health (USA); OHSA, Oupational Health and Safety Administration (USA); ppm, parts per million; TWA, time-weighted average Table 3 Tobao Manufaturers Assoiation benhmark values for onentration of aromati amines in sidestream tobao smoke in ng (from National Institute for Oupational Safety and Health Poket guide to hemial hazards) 7 Aromati amines Benhmark mean/ igarette (n = 144) Standard deviation 1-aminonaphthalene aminonaphthalene aminobiphenyl aminobiphenyl Current test results/moxa stik were found, with most samples of outdoor air showing aromati amine levels lower than 40 ng/m Although these readings are for a wider range of aromati amines, they provide useful omparison with the figures deteted in the tests of moxa, where the highest figure reorded expressed as a longterm time-weighted average was only 0.8 ng/m 3. Two fators arose in the preparation of the analysis whih warrant further study. First, although moxa was tested in stik form and the volatile by-produts of ombustion tested and quantified, moxa is also used diretly on the skin by some pratitioners and when used in this way leaves a slight oily residue. Korinth et al report a number of ases where dermal absorption of aromati amines has been linked to aners. 11 The exposure of most patients to aromati amines through diret moxa use will be infinitesimal in omparison to some of the industrial proesses for whih these trials were arried out, but the report did indiate that a damaged epidermal barrier signifiantly inreased the existing risk of absorption. Aupunt Med: first published as /aim on 1 Marh Downloaded from on 8 Otober 2018 by guest. Proteted by opyright. Aupunt Med 2009;27: doi: /aim

5 Summary points Smoke from mouldering moxa may be hazardous to health This study analysed moxa smoke for onentrations of known harmful onstituents Conentrations of three substanes ould ause onern under abnormal operating onditions Pratitioners should onsider ventilation of lini rooms, and the use of moxa on broken skin Professional aupunture bodies may have to assess whether their guidelines on moxa use may have to be adjusted to take this into aount, and several already forbid the use of moxa on broken skin. Wider researh into the dispersal of potentially harmful onentrations of volatiles by improved ventilation may need to take into aount the onlusions of Kotzias et al into the effet of ventilation on the redution of air pollution from environmental tobao smoke. 12 It has been argued that potential risks ould be redued by better ventilation. Kotzias et al found, however, that many of the more dangerous volatiles stuk to internal surfaes rather than remaining in suspension in the air, aounting for the smell of smoke lingering in a room for many days after it has first been produed. The authors onlude that diffusion of the emitted ompounds (sidestream smoke and burning produts) is relatively slow, so dilution via mixing with new inoming fresh air is not very effetive as a ontrol measure. 12 Furthermore, Kotzias et al onlude that wind-tunnel like rates of dilution ventilation would be neessary to ahieve the kinds of redution in pollutants to equivalent levels in ambient air. 12 This may also have to be fatored into any new reommendations to pratitioners, sine it may be more important to lean or over surfaes in the room regularly than to insist on investment in air onditioning or ventilation plant. A great deal depends, however, on the rate of oxidation of some of the volatiles involved, many of whih have a relatively short life span in their more dangerous forms. This in turn may be affeted by the nitrogen ontent and ombustion temperature of the moxa; one study in Ameria pointed to a diret orrelation of both of these fators to the amount of aromati amines produed by igarette smoke. 13 CONCLUSION In summary, the results of testing moxa for safe use are enouraging, and the by-produts of ombustion do not appear to be generated in suffiient quantities to ause onerns about exeeding the agreed industrial safety standards. Where some analytes approah urrent safe exposure limits in the tests and extrapolated results, this an be explained by the assumptions in the extrapolations from the test results whih reflet highly improbable onentrations of smoke. Aknowledgements: The authors would like to thank Ulrike Wirth (BAC Safe Pratie Offier), Mark Bovey (Aupunture Researh Resoure Centre), Dr Mike Cummings (BMAS), and Dr Helen Taylor and Dr Tatiana Humphreys (Arista Laboratories) for their help and advie in the preparation of this paper. The British Aupunture Counil, whih funded the study, would also like to thank Arista Laboratories, Rihmond, Virginia for their help and advie. Competing interests: The study was funded by the Exeutive Committee of the British Aupunture Counil in response to questions posed by patients. The analyses were onduted by an independent laboratory. The authors, two of whom (BC and CC) are members of the Exeutive Committee, onverted the data, loated the published maximum exposure limits for omparison and interpreted the findings. The BAC Exeutive Committee itself played no role in the interpretation of data or preparation of this report. REFERENCES 1. Sakagami H, Matsumoto H, Satoh K, et al. 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