Gaseous fluorine and ammonia emissions from two pulverized-coal power plants were measured over a 6-month period. In one unit, emissions contained a median 1.5 mg/scm (standard cubic meter) NH3 and 1.9 mg/scm F (86% of available F in coal). For the other unit lower levels were found: 0.042 mg/scm NH3 and 0.22 mg/scm F (4.2% of available F in coal). Ammonia varied by more than 10 times in each unit and was enhanced in Unit I by addition of ammonium carbonate to improve precipitator efficiency. Fluorine varied less than 50% in each unit. The difference in F between units was related circumstantially to ash content. Daily variation of F and NH3 was less than 20%. Neither gas was in sufficient quantity relative to SO2 to influence net acidity. Levels of F were comparable to those of other combustion sources and the aluminum industry. On a global scale, coal combustion is not a major source of either F or NH3. Among anthropogenic sources, however, it is a significant contributor and may be important locally. In contrast, NH3 emissions are negligible.