As Nikisa said this morning, it is very hot and hazy. As you can see on the MODIS IDEA image, there is a plume of aerosols along the East coast extending from Maine to Georgia. This increased AOD is also confirmed by ground-based measurements. PM2.5 monitoring sites registered PM levels ranging from about 15 ug/m3 to 40 ug/m3. Ozone levels in Baltimore county were 100 ppb at 3:00pm. PM2.5 concentrations in Baltimore reached 39 ug/m3, which is very close to being characterized as “unhealthy for sensitive groups”. On the MODIS Direct image below, the haze is circled in red. For comparison, one of the locations with minimal haziness is circled in yellow.
MODIS IDEA and MODIS Direct images