Effect of industrial point-source air pollutants on fractional exhaled nitric oxide in healthy volunteers.

•Ambient NO2, SO2 and PM 2.5 concentrations were greater near a steel plant than on a college campus.•Proximity to a steel plant was associated with increased exhaled nitric oxide concentrations.•Exhaled nitric oxide was higher on days of higher NO2 concentrations.•The AQHI, a summary measure of pollutants was positively correlated with exhaled nitric oxide.