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.
Industrial smog occurs in foggy, cool weather typical of that experienced in the British Isles and the eastern seaboard of the United States. Photochemical smog, on the other hand, occurs in hot, dry climates, and particularly on sunny days. Cities noted for this type of smog, such as Los Angeles, Tokyo and Mexico City, are typically surrounded by mountains that prevent air circulation. While industrial smog is most intense in the early morning, photochemical smog peaks at midday.