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
According to the dictionary, air pollution is the contamination of air by smoke and harmful gases, mainly oxides of carbon, sulfur, and nitrogen. (And maybe by that smelly uncle.) Some examples of air pollution include: Air pollution is linked to asthma, allergies and other respiratory illnesses.