Apparently all the crud from the DC fireworks drifting southeast (air quality, not good). https://map.purpleair.com/air-quality-standards-us-epa-aqi?opt=%2F1%2Flp%2Fa10%2Fp604800%2FcC0#10.69/38.8328/-77.1285
ALT
Replying to @ai6yr@m.ai6yr.org
@ai6yr My sensor plots from about 16km from the mall. Lots of fireworks in my vicinity, even during the height of the thunder storm.
ALT