Thousands of residents across a part of west-central Florida —including areas surrounding St. Petersburg—have been advised to stay inside as of Monday at 5.30 a.m. ET, because a pocket of fine particle pollution (PM2.5) has reached a level that is considered, by the Environmental Protection Agency ( EPA ), to be “ unhealthy for sensitive groups ,” according to the EPA’s AirNow map, which records and monitors the air quality across America in near-real time. Although the EPA has not established