( ( Primary pollution ) ( ( is ( ( emitted directly ) ( into ( the atmosphere ) ) ) ) ; ) )
(ROOT (S (NP (JJ Primary) (NN pollution)) (VP (VBZ is) (VP (VBN emitted) (ADVP (RB directly)) (PP (IN into) (NP (DT the) (NN atmosphere))))) (: ;)))
Primary pollution is emitted directly into the atmosphere;
(ROOT (S (NP (JJ Primary) (NNS pollutants)) (VP (VBP enter) (NP (DT the) (NN air)) (ADVP (RB directly))) (. .)))