Brooklyn residents felt the heat for the third day in a row Tuesday, with temperatures passing 90 degrees.

Construction workers, Postal Service workers and food vendors say it's not easy to work outside during a heat wave, but they have become accustomed to it. Experts, however, say the high heat index combined with soaring temperatures and humidity and the poor air quality can make working and spending too much time outdoors a health hazard.

To avoid heat-related illnesses, experts say residents and workers should keep hydrated, take breaks and try to go indoors, if possible.