Unsure how many sensors they have in other metros, but here in the Salt Lake Valley, the Purple network does a great job of this. https://www.purpleair.com/map

Unsure how many sensors they have in other metros, but here in the Salt Lake Valley, the Purple network does a great job of this. https://www.purpleair.com/map?opt=1/i/mAQI/a10/cC0#11.37/40.6634/-111.7754 https://www.purpleair.com/map?opt=1/i/mAQI/a10/cC0#11.37/40....