Acidic gases, NH(3) and secondary inorganic ions in PM(10) during summertime in Beijing, China and their relation to air mass history.

In the summers of 2002-2003, acidic gases, ammonia and water-soluble ions in PM(10) were measured in Beijing. The mean concentrations of HCl, HONO, HNO(3), SO(2) and NH(3) are 0.6, 3.