Influence of calcination process on the formation of selected air pollutants Jacek Wydrych, Bolesław Dobrowolski, Grzegorz Borsuk and Sławomir Pochwała E3S Web Conf., 19 (2017) 02002 Published online: 23 October 2017 DOI: 10.1051/e3sconf/20171902002