How much can dirt reduce solar panel output?
Estimates of global airborne particle deposition (Seinfeld and Pandis: "Atmospheric Chemistry and Physics") show average rates of over 26 kg/m²/yr.
We have found 53 studies from around the world on the effects of dust on solar panel efficiency. We created the full list for those who have an interest in this research - click here.
At right is a map that depicts the locations and results of some of the studies.
The studies also showed that to keep losses below 3%, weekly cleaning was essential.
Our paper, "Cleaning Solar Panels" covers this topic in full details: it's a 3MB download - click here.