>>800967Are you talking about sciaridae? (fungus gnats)
They're harmless to humans (their buccal pieces do not allow them to bite skin), and almost-harmless to plants. Some say they eat roots, but it's extremely rare : it happens only when your roots are already rotting (so in already bad shape). They are symptomatic of an excessive humid soil, but tend to persist a little once this problem is solved.
Try to space your waterings (so as the surface soil stay dry for several days), water by the bottom, and their number will decrease.
You can also lay some cups of yellow color with soapy water. Some have good results with cups of coffee, the thing is to encourage them to land on the water (by example by putting a light just above it)