"Freebasing" is well known in the USA among those who use "crack cocaine" or heroin. They may or may not know that the word, "free base" comes from a chemical term for the neutral (uncharged) form of an amine. In freebasing of crack cocaine, for example, the positively charged "salt" form of cocaine, is heated with sodium bicarbonate or ammonia to convert the cocaine into a neutral amine form, the free base form of cocaine. This "free base" molecular form of cocaine is more volatile (vapourises more easily) and also is absorbed more rapidly into the bloodstream by the lining of the lungs, so it produces a rapid "kick" and enhances and perpetuates cocaine addiction and its concomitant dangerous health hazards.
Well, studies, including investigations of tobacco company records, indicate quite clearly that tobacco companies are well versed about freebasing. For decades, they have been adding ammonia to cigarettes. They claimed it was added to flavour cigarettes to give them a "chocolatey" taste, as well as for other reasons, but data indicates that they knew full well that ammonia can convert the "salt" form of nicotine to its free base. In other words, the addition of ammonia to cigarettes is really a way of making smokers "freebase" nicotine, just as crack cocaine addicts freebase cocaine, and so enhance the "kick" and addictiveness of cigarettes.
To summarise, tobacco companies add ammonia to cigarettes, knowing that it is a form of freebasing, increasing the nicotine dose that a smoker gets and enhancing its ability to be absorbed into the bloodstream and reach the brain, and so increasing the addictiveness of cigarettes, and so again of making sure that cigarette sales and their profits continue to do well.
So, if you are a smoker, the next time you smoke a cigarette, remember that you are "freebasing" nicotine, and the tobacco industry has known for years that you’ve been doing this, but never told you or anyone else.