U.S. Air Quality

Moderate PM2.5, record heat, and Fire Weather Watch over Northeast United States

Moderate PM2.5 AQI were recorded again today across the Mid-Atlantic and Northeast states as unabated southerly wind flow surged the region's high temperatures into the 80-90°F range, surpassing records for locations like Boston, Massachusetts which hosted its annual Boston Marathon (top left, courtesy AIRNow; top right, courtesy MesoWest). Elsewhere, Code Orange (Unhealthy for Sensitive Groups) PM2.5 AQI were observed over eastern Oregon and Tennessee. The HMS Fire and Smoke analysis indicates an area of what is likely remnant smoke (from wildfires burning in western Virginia) juxtaposed to the Mid-Atlantic and Northeast coastline, and suggests the most dense smoke is concentrated northeast of Massachusetts (bottom left). The mild and dry air mass over the northeast today also prompted the National Weather Service to issue a Red Flag Warning and Fire Weather Watch as the environment became favorable for fires to spread (bottom right).