State air monitors in Roxbury, Dorchester, Chinatown and Chelsea are currently showing levels of pollutants in the area that are "unhealthy for sensitive groups:" carbon monoxide, nitrogen dioxide, ozone and "fine particles" in Roxbury; carbon monoxide, nitrogen dioxide and fine particles in Dorchester; fine particles in Chinatown and Chelsea.
If you're five to seven miles outside of downtown Boston, the city appears to be lost in haze.