( ( ( ( ( to ( air pollution ) ) ( , ( ( ( such ( as ( air ( quality monitoring ) ) ) ) and ) ( impacts ( of air ) ) ) ) ) pollutants ) ( on ( natural systems ) ) ) ; )
(ROOT (NP (NP (NP (UCP (PP (TO to) (NP (NN air) (NN pollution))) (, ,) (PP (JJ such) (IN as) (NP (NN air) (NN quality) (NN monitoring))) (CC and) (NP (NP (NNS impacts)) (PP (IN of) (NP (NN air))))) (NNS pollutants)) (PP (IN on) (NP (JJ natural) (NNS systems)))) (: ;)))
to air pollution, such as air quality monitoring and impacts of air pollutants on natural systems;
(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))))) (. .)))