What dirties solar panels in St. Petersburg
Salt aerosol from three sides
Tampa Bay to the east, Boca Ciega and the Gulf to the west. Very few St. Pete homes are more than a mile from salt water, and salt film re-establishes within weeks of every clean.
Bird activity
Gulls, pelicans and pigeons are constant, especially near the waterfront parks and downtown. Droppings are acidic and fully opaque.
Traffic and downtown grit
I-275, 4th Street and the downtown core add a fine carbon film that binds to the salt already on your glass.