( ( ( A summary ) ( of ( the ( primary criteria ) ) ) ) ( ( air ( pollutants ( follows ( for reference ) ) ) ) . ) )
(ROOT (S (NP (NP (DT A) (NN summary)) (PP (IN of) (NP (DT the) (JJ primary) (NNS criteria)))) (VP (NN air) (SBAR (S (NP (NNS pollutants)) (VP (VBZ follows) (PP (IN for) (NP (NN reference))))))) (. .)))
A summary of the primary criteria air pollutants follows for reference.
(ROOT (S (NP (JJ Primary) (NNS pollutants)) (VP (VBP enter) (NP (DT the) (NN air)) (ADVP (RB directly))) (. .)))