The AirNow image above shows a good level of Ozone and Particulate Matter above Baltimore. The lack of color above the Baltimore region shows that the Air Quality was between 0-50.
The AirNow Tech image above supports this claim as the Particulate matter levels in ceilometers was well below 50 throughout the whole day.
The Copernicus Global Forcast Image above shows that on May 30th there was a high concentration of biomass aerosols being released from Central Africa. Within the regions of Angola and Democratic Republic of Congo there is a bright red spot that shows a high level of Biomass Aersols being released.
The NRL/Monterey Aersol image above supports this claim as the smoke surface concentration reaches between 128-256 ug/m3 (light purple).
The Global Fire Watch image above shows an increased concentration of Hotspots in the Central Africa region. The increased concentration of smoke may be due to crop fires that are often started during this time. NASA reported that a similar pattern of fires was seen in 2020 and these fires are started to clear the fields before planting a new crop.