The air cyclists breathe

Bicyclists in lanes separated from active traffic by a row of parked cars breathe in less pollution

On weekdays, Darby Jack bicycles the 15 miles from his home in Clinton Hill, Brooklyn, to his office at Columbia University’s Mailman School of Public Health in Washington Heights. Unlike most people who bike to work, the 42-year-old assistant professor of environmental health wears sensors that monitor how much air he breathes in during the trip along with air pollution levels along his route.

This elaborate gadgetry is part of a five-year study that aims to find out at what point the harm done by pollution to cyclists might outweigh the health benefits accrued from the exercise.

The strapped-on sensors measure levels