( ( primary ( pollutants Chemicals ) ) ( ( ( released directly ) ( into ( ( the air ) ( in ( a ( harmful form ) ) ) ) ) ) . ) )
(ROOT (S (NP (JJ primary) (NNS pollutants) (NNS Chemicals)) (VP (VBD released) (ADVP (RB directly)) (PP (IN into) (NP (NP (DT the) (NN air)) (PP (IN in) (NP (DT a) (JJ harmful) (NN form)))))) (. .)))
primary pollutants Chemicals released directly into the air in a harmful form.
(ROOT (S (NP (JJ Primary) (NNS pollutants)) (VP (VBP enter) (NP (DT the) (NN air)) (ADVP (RB directly))) (. .)))