A-Over time, even with good teeth cleaning, plaque and tartar can attach to the teeth similar to lime build-up in a kettle or iron. The saliva fluids in our mouths contain calcium and bacteria.-According to oral hygiene standards, it is recommended that patients visit the dentist every six months for an oral health check-up, to discuss any medical changes such as new medications that can affect oral wellbeing, and to have teeth cleaned with scaling and polishing where necessary.
Industrial smog occurs when the smoke and sulfur dioxide produced from burning coal merges with fog and creates a yellowish-brown-colored haze close to ground level. Photoch â¦ emical smog forms as the result of increased usage of all fossil fuels, including gasoline and the burning of trees and organic waste.
Found this at a smog check center: In my experience, it was engine oil caused by a defective head gasket. The oil was leaking out and burning off from the heat of the engine. The oil dripping onto the floor was clear and slightly brown, and the smoke was white (as Al says, probably to my untrained eye). Views Â· View Upvotes.