Eficiencia germicida (%) de los AE

There has been extensive research on the effects of tobacco smoke and its biological effects. According to Hall et al. (1999:101) and Iversen (2000:191 &193), marijuana smoke has similar components to tobacco smoke and can

therefore make useful predictions about the effects of marijuana smoke on individuals. More than 6000 chemical constituents have been identified in tobacco smoke. These can be dependent on the wrapping paper, which can alter the burning characteristics, which, in turn, can alter the chemical components of the smoke.

Although significant links between long-term cannabis use and chronic obstructive lung disease are yet to be established, Zimmer and Morgan (1997 cited in Iversen, 2000:200) argue that marijuana smoking has only recently become increasingly widespread. Insufficient numbers of people have therefore had long-term exposure to marijuana smoking for a clear link between marijuana and lung disease and cancer to be established. Iversen (2000:200) argues that links between marijuana smoking and lung diseases should be considered given the relatively long period of time that elapsed before links were made between tobacco smoking and lung cancer.7

In 1987 Professor Tashkin from the Department of Medicine at the University of California conducted a study that examined the effects of marijuana and tobacco on the lungs of consumers. Tashkin (1987) compared 144 marijuana-only smokers with 135 people who smoked both tobacco and marijuana. He also studied 70 tobacco-only smokers and 97 non-smokers. Tashkin (1987) found that 20 per cent of both tobacco and marijuana smokers who consumed three to four joints and more than 20 cigarettes a day developed symptoms of chronic bronchitis. Those who smoked both tobacco and marijuana did not present any

7 _{Tobacco smoking became commonplace among men early in the 19}t_{th century and it was not}

until the 1950s that a link was made between tobacco smoking and cancer of the lungs, mouth, throat, larynx and pancreas. It took a good forty to fifty years for these diseases to be linked to long-term tobacco smoking and it is perhaps a matter of time before such links are made to long-term marijuana smoking (Iversen, 2000:198–199; Hall & Pacula, 2003:37).

dependency effects (Tashkin 1987 cited in Tashkin, 1999:320—321; Tashkin 1987 cited in Iversen, 2000:195; Tashkin 1987 cited in Hall & Pacula, 2003:62).

In a follow-up study conducted in 1997, Tashkin found that over a ten-year period, tobacco smokers’ lung function had worsened, making them more likely to develop chronic obstructive lung disease (Tashkin 1997 cited in Tashkin, 1999:323; Tashkin 1997 cited in Iversen, 2000:195; Tashkin 1997 cited in Hall et al., 1999:102). There were no such changes observed in marijuana smokers. Tashkin therefore suggested that they are less likely to develop such lung problems than tobacco smokers (Tashkin 1997 cited in Tashkin, 1999:323; Tashkin 1997 cited in Iversen, 2000:195; Tashkin 1997 cited in Hall et al., 1999:102).

Wu et al. (1988 cited in Hall & Pacula, 2003:63) conducted a study that compared the toxicity of cannabis smoke to that of tobacco smoke. The study found that because cannabis smokers inhale more deeply than tobacco smokers, cannabis smokers are likely to inhale 40 to 54 per cent more smoke than tobacco smokers (Wu et al. 1988 cited in Hall & Pacula, 2003:63). Their study further compared the level of tar and carbon monoxide absorbed by regular tobacco and marijuana users. When comparing a single filtered tobacco cigarette with a marijuana cigarette, marijuana smoke resulted in four to five times the amount of carbon monoxide and tar absorbed (Wu et al. 1988 cited in Iversen, 2000:193).

The toxicity of cannabis smoke as opposed to tobacco smoke is supported by Hall et al. (1999:101), Iversen’s (2000:193) and Goldberg (2009:248) who argue that reports show that carcinogens and other chemicals, such as

benzanthracene, benzpyrene ammonia and hydrogen cyanide, are more prevalent in marijuana smoke than tobacco smoke. This coupled with the way in which some users smoke cannabis is said to potentially enhance the dangers of its use. Cannabis smokers generally inhale more deeply than tobacco smokers, therefore increasing the absorption of tetrahydrocannabinol (THC) and carbon monoxide in the lungs (Upfall, 2002:104). It has not yet been proven that cannabis causes lung cancer, however studies according to Goldberg (2009:248) have shown damage to the wall lining of the airways in humans. It has been reported that cannabis smokers exhibit pathological changes in their lungs, 20 years before tobacco smokers (Goldberg, 2009:248).

Given the health effects that can be attributed to both tobacco and cannabis and others that can be attributed to one but not the other (Hall & Pacula, 2003:136), there appears to be little logic in prohibiting a drug that has been legal for decades and legalising a drug that has been illegal for decades. According to Hall and Pacula (2003:135), chronic tobacco and cannabis smoking can cause the same respiratory diseases and cancer of the aerodigestive tract. Although there have been chronic health problems associated with tobacco smoking, such as cancer of the cervix, stomach and bladder, these have yet to be attributed to cannabis smoking. Psychological diseases such as schizophrenia have been associated with cannabis but not with tobacco (Hall & Pacula, 2003:136–137). This is particularly significant given the accelerating social acceptance of cannabis use and the subsequent increase in the demonisation of tobacco use.

With pressure mounting on the government to outlaw the use of tobacco and legalise the use of cannabis particularly for medical purposes, research on the health effects of cannabis use does little to support the argument for cannabis

legalisation. The anti-tobacco campaign, particularly in Victoria, has focused on banning tobacco smoking in restaurants, enclosed workplaces and pubs, with significant success (Victorian Department of Human Services, 2007:1). In 2010 smoking in cars where children are present was banned and a move to ban tobacco smoking in private residences is under debate (Department of Health, 2010).