Photo date: October 26, 2016. Photographer: Mark Mahin.
The photo below (taken on a dry night) shows a huge swarm of orbs above a
building in New York City. My eyes could not notice anything unusual
in the air, and there was no unusual smell. A photo taken about 20 seconds later from the same angle showed not a single orb.
There was no fog, mist, rain or precipitation on this night. The air quality listed on airnow.gov was "good," with a level of 27 (anything below 50 is good). The pollen level listed on pollen.com was low, with a level of 1.1.
An orb in the top right corner of the photo has a thick stripe, although you will only notice it if you click on the photo and view it in a separate browser tab.