( nitrogen ( ( oxides ( ( ( Highly reactive ) gases ) ( formed ( ( ( when ( ( nitrogen ( in ( fuel ( or ( combustion air ) ) ) ) ) ( is ( ( heated ( to ( ( over 650C ) ( -LRB- ( ( 1200 F ) -RRB- ) ) ) ) ) ( in ( ( the presence ) ( of oxygen ) ) ) ) ) ) ) or ) ( when ( ( bacteria ( in ( ( soil or ) water ) ) ) ( oxidize ( nitrogen-containing compounds ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NN nitrogen)) (VP (VBZ oxides) (SBAR (S (NP (ADJP (NNP Highly) (JJ reactive)) (NNS gases)) (VP (VBD formed) (SBAR (SBAR (WHADVP (WRB when)) (S (NP (NP (NN nitrogen)) (PP (IN in) (NP (NN fuel) (CC or) (NN combustion) (NN air)))) (VP (VBZ is) (VP (VBN heated) (PP (TO to) (NP (NP (QP (IN over) (CD 650C))) (PRN (-LRB- -LRB-) (NP (QP (CD 1200) (CD F))) (-RRB- -RRB-)))) (PP (IN in) (NP (NP (DT the) (NN presence)) (PP (IN of) (NP (NN oxygen))))))))) (CC or) (SBAR (WHADVP (WRB when)) (S (NP (NP (NNS bacteria)) (PP (IN in) (NP (NN soil) (CC or) (NN water)))) (VP (VBP oxidize) (NP (JJ nitrogen-containing) (NNS compounds)))))))))) (. .)))
nitrogen oxides Highly reactive gases formed when nitrogen in fuel or combustion air is heated to over 650C (1200 F) in the presence of oxygen or when bacteria in soil or water oxidize nitrogen-containing compounds.
(ROOT (S (NP (NNP Nitrogen)) (VP (VBZ oxide) (NP (NP (NN form)) (PRN (-LRB- -LRB-) (PRP s) (-RRB- -RRB-)) (SBAR (WHADVP (WRB when)) (S (NP (NN nitrogen) (CC and) (NN oxygen)) (VP (VBP combine) (PP (IN at) (NP (JJ high) (NNS temperatures)))))))) (. .)))