( ( ( 2 ( Ground ( Level ( Ozone Concentrations ) ) ) ) ( in ( ( North ( Carolina ( Ambient levels ) ) ) ( of ozone ) ) ) ) ( ( vary ( by ( ( ( ( ( ( ( region , ) ( time ( of day ) ) ) , ) ( ( the presence ) ( of ( ozone-forming compounds ) ) ) ) , ) and ) ( weather conditions ) ) ) ) . ) )
(ROOT (S (NP (NP (CD 2) (NNP Ground) (NNP Level) (NN Ozone) (NNS Concentrations)) (PP (IN in) (NP (NP (NNP North) (NNP Carolina) (NNP Ambient) (NNS levels)) (PP (IN of) (NP (NN ozone)))))) (VP (VBP vary) (PP (IN by) (NP (NP (NN region)) (, ,) (NP (NP (NN time)) (PP (IN of) (NP (NN day)))) (, ,) (NP (NP (DT the) (NN presence)) (PP (IN of) (NP (JJ ozone-forming) (NNS compounds)))) (, ,) (CC and) (NP (NN weather) (NNS conditions))))) (. .)))
2 Ground Level Ozone Concentrations in North Carolina Ambient levels of ozone vary by region, time of day, the presence of ozone-forming compounds, and weather conditions.
(ROOT (S (NP (NN Ozone)) (VP (VBZ is) (NP (NP (DT a) (NN compound)) (VP (VBN formed) (SBAR (WHADVP (WRB when)) (S (NP (EX there)) (VP (VBZ is) (VP (VBG sparking) (NP (JJ electrical) (NN equipment))))))))) (. .)))