Asked July 13, 2016, 4:25 PM EDT
Wood County Ohio
My initial response would be fungus gnats, fruit or vinegar flies, or drain flies. Fungus gnats thrive in damp highly organic soils like those found in house plants and outdoors in mulch. Fruit flies and vinegar flies thrive on overly ripe fruit, and rotten trash stuck on bottom of waste trash cans. Finally drain flies thrive in drains and thrive in the gunk caught in drains,
However I do not think you are dealing with these types of small flies or gnats. When you mentioned several buildings in the area have same issue, it tends to rule out the above due to the hot dry conditions we are experiencing this summer.
The gnat you’re dealing with is most likely the Boxwood Psyllid Cacopsylla busi (Linnaeus).
Check out this web site from Maryland: https://extension.umd.edu/hgic/boxwood-psyllid-shrubs
The adult is making its presence now in Northern Ohio. The Boxwood Shrub Buxus spp. Is a common landscape plant installed around the foundations of buildings The adult is gaining entry via open doors and loose fitting window screens.
Hope this helps! Craig