cause of smoking cigarettes Smoking's Disease Burden: Worse than Previously Thought? 9 Health Effects of Smoking
Description
Some people prefer gum to the patch because they can control the nicotine dosage, and chewing satisfies the oral urge associated with smoking

#4 is specifically related to space travel

If you are a smoker, there are resources available to help you quit
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How much nicotine is really in a cigarette
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This loss causes some air to remain in the lungs after exhaling
