The results of a large scale (N=1001) cross-sectional (Years 6, 8 and 10) study of students' ideas about the composition of unpolluted air, the nature of air pollution, the biological consequences of air pollution, and about acid rain and the Greenhouse Effect are reported. A range of persistent alternative conceptions were identified, in some instances with increasing frequency across grades. Students' attitudes towards education, obligation, legislation or taxation as a way of reducing air pollution were determined; the first two were the most favoured. Increased attention to particular gas and air pollution concepts is recommended; other pedagogical implications are discussed.