Is the marginal benefit of an organic/chemical free lifestyle offset by environmental pollution in a metropolitan city.

I was having an argument with my sister, who avoids chemicals (ie. she won't use Lamisil for athletes foot but uses oregano oil) and buys organic produce. I maintain that any benefit (perceived or otherwise) is completely offset by the harm provided by the environmental impact of living in NYC (ie. car fumes, subway dust, pollution).

That is to say, living in a metropolitan city is so much more detrimental than any benefit of an organic lifestyle the effort is futile. Am I right?