Apparently all the crud from the DC fireworks drifting southeast (air quality, not good). map.purpleair.com/air-quality-…
US EPA PM2.5 Air Quality Standards Interactive Map by PurpleAir
Watch: With two minute updates, The US EPA PM2.5 Air Quality Index (AQI) is a number used by US government agencies to communicate to the public how polluted the air currently is or how polluted it is forecast to become.PurpleAir
