( ( An ( air ( pollutant ( concentrations inventory ) ) ) ) ( ( summarizes ( ( the results ) ( of ( monitoring ( ambient ( air pollutants ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT An) (NN air) (NN pollutant) (NNS concentrations) (NN inventory)) (VP (VBZ summarizes) (NP (NP (DT the) (NNS results)) (PP (IN of) (S (VP (VBG monitoring) (NP (JJ ambient) (NN air) (NNS pollutants))))))) (. .)))
An air pollutant concentrations inventory summarizes the results of monitoring ambient air pollutants.
(ROOT (S (NP (NP (NNP Ash)) (SBAR (WHNP (WDT that)) (S (VP (VBZ enters) (NP (DT the) (NN air)) (PP (ADVP (RB naturally)) (IN as) (NP (NP (DT a) (NN result)) (PP (IN of) (NP (DT a) (NN volcano) (NN eruption))))))))) (VP (VBZ is) (VP (VBN classified) (PP (IN as) (NP (DT a) (JJ primary) (NN pollutant))))) (. .)))