As the temperature climbs this week, air quality is expected to deteriorate to conditions unhealthy for many people, according to forecasts.
"Code Orange" level air quality is expected Thursday and Friday, according to data reported by the Maryland Department of the Environment to Washington-based Clean Air Partners.
Forecasts call for sunny skies with temperatures in the upper 80s on Thursday, the National Weather Service said. Overnight temperatures will drop to the mid-60s and low-70s in the region, but will rise again under sunny skies on Friday to the lower 90s.
As of 4:54 p.m., it was 88 at BWI. Temperatures appeared to peak at 91 around 2 p.m.
Temperatures are expected to remain high through the weekend.
Code Orange air quality levels are considered unhealthy for sensitive groups, which include children, the elderly and people with respiratory conditions.
It is the first "Code Orange" day so far this year in the Baltimore area, according to AirNow.gov.
The Air Quality Index takes into account concentrations of five pollutants in the air -- sulfur dioxide, carbon monoxide, nitrogen dioxide and ozone.
Ozone is a key concern during summer months because heat and sunlight cause the pollutant to proliferate more rapidly.
Abundant sunshine and highs in the 90s are forecast Thursday through Sunday in the Baltimore area.