( in ( ( ( ( the air ) & ) that ) ( ( makes ( it ( difficult ( to breathe ) ) ) ) . ) ) )
(ROOT (S (ADVP (RB in)) (NP (NP (DT the) (NN air)) (CC &) (NP (DT that))) (VP (VBZ makes) (S (NP (PRP it)) (ADJP (JJ difficult) (S (VP (TO to) (VP (VB breathe))))))) (. .)))
in the air & that makes it difficult to breathe.
(ROOT (S (NP (NNP Narrow) (NN air) (NNS passages)) (VP (VBP make) (S (VP (VBG breathing) (ADJP (JJ difficult) (RB due) (S (VP (TO to) (VP (VB respiratory) (NP (NN system) (NN disease))))))))) (. .)))