Living in proximity to a subway line doesn't necessarily mean you spend more time on the subway than people who live further away, nor does it mean that you use

Living in proximity to a subway line doesn't necessarily mean you spend more time on the subway than people who live further away, nor does it mean that you use the subway more. Subway commuters who can't afford to live close to a subway line probably live further from their workplaces, too, which would mean they spend more time on the subway and have more transfers between lines. Those people may then carry germs back to their neighborhoods. The subway is a shared space with poor air quality and many hard surfaces that are touched by many people every hour. The blog post you are "citing" tries to draw conclusions by zip code in a map that is not granular enough to support the claims. You yourself acknowledge this so I'm not sure why you use that blog post as evidence. Also, Jeff Harris (the MIT professor who wrote the paper with which the blogger disagrees) is a doctor as well as being an economist. That doesn't mean he is infallible, but I wouldn't be so quick to dismiss his thoughts.