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<p>I would not be surprised if the percentage of smokers in NYC is now much lower than when you were growing up (or in 1978, when the paper linked was published). Of course, air pollution from other sources was also generally much worse back then.</p>
<p>This is not to say that secondhand smoke is not an annoyance that has some health hazard. But it is somewhat more avoidable today than decades ago.</p>