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
Over time, once one quits smoking, the lungs are able to renew themselves and we cough out a lot of the crap. Probably the best thing you can do after breathing a lot of dust would be to get yourself to the cleanest air you can find, bearing in mind that air-conditioned air is usually cleaner than outside air. Stay there for as long as you can - sleep there, if possible! There's really not a lot else you CAN do.