( ( Since ( ( some water ) ( always ( exists ( ( ( ( ( in ( the ( sales ( gas composition ) ) ) ) , ) even ) ( if only ) ) ( at ( the ( ppm level ) ) ) ) ) ) ) ) ( , ( ( ( any change ) ( in ( the ( atmospheric ( ( temperature or ) pressure ) ) ) ) ) ( ( can ( ( cause ( the ( water vapor ) ) ) ( to ( condense ( in ( the pipelines ) ) ) ) ) ) . ) ) ) )
(ROOT (S (SBAR (IN Since) (S (NP (DT some) (NN water)) (ADVP (RB always)) (VP (VBZ exists) (PP (PP (PP (IN in) (NP (DT the) (NNS sales) (NN gas) (NN composition))) (, ,) (ADVP (RB even))) (CONJP (IN if) (RB only)) (PP (IN at) (NP (DT the) (NN ppm) (NN level))))))) (, ,) (NP (NP (DT any) (NN change)) (PP (IN in) (NP (DT the) (JJ atmospheric) (NN temperature) (CC or) (NN pressure)))) (VP (MD can) (VP (VB cause) (NP (DT the) (NN water) (NN vapor)) (S (VP (TO to) (VP (VB condense) (PP (IN in) (NP (DT the) (NNS pipelines)))))))) (. .)))
Since some water always exists in the sales gas composition, even if only at the ppm level, any change in the atmospheric temperature or pressure can cause the water vapor to condense in the pipelines.
(ROOT (S (NP (NNP Water) (NN vapor)) (VP (VBZ exists) (PP (IN in) (NP (NP (DT the) (NN atmosphere)) (PP (IN as) (NP (DT an) (JJ invisible) (NN gas))))))))
Water vapor exists in the atmosphere as an invisible gas