Definition: Sibilance is a sound characterized by pronouncing words with the letter 's'. In audio reproduction the letter 's' should sound clear and distinct, not smeared or distorted as in 'sh'.
High air pollution levels can cause immediate health problems including: Aggravated cardiovascular and respiratory illness; Added stress to heart and lungs, which must work harder to supply the body with oxygen; Damaged cells in the respiratory system
1 Unfortunately, they're also a form of air pollution: they're believed to have long-term (chronic) effects on people's health and they also play a role in the formation of ozone and smog. 2  Particulates: These are the sooty deposits in air pollution that blacken buildings and cause breathing difficulties.hoto: Air pollution is obvious when it pours from a smokestack (chimney), but it's not always so easy to spot.