( ( ( This effect ) ( on ( plume concentration ) ) ) ( ( ( could best ) ( be ( ( ( modeled ( with ( a ( particle ( trajectory model ) ) ) ) ) , ) ( since ( ( these models ) ( ( estimate ( ( the concentration ) ( at ( a receptor ) ) ) ) ( by ( counting ( ( the number ) ( of ( times ( ( a particle ) ( is ( seen ( in ( the ( receptor volume ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT This) (NN effect)) (PP (IN on) (NP (NN plume) (NN concentration)))) (VP (MD could) (ADVP (RBS best)) (VP (VB be) (VP (VBN modeled) (PP (IN with) (NP (DT a) (NN particle) (NN trajectory) (NN model))) (, ,) (SBAR (IN since) (S (NP (DT these) (NNS models)) (VP (VBP estimate) (NP (NP (DT the) (NN concentration)) (PP (IN at) (NP (DT a) (NN receptor)))) (PP (IN by) (S (VP (VBG counting) (NP (NP (DT the) (NN number)) (PP (IN of) (NP (NP (NNS times)) (SBAR (S (NP (DT a) (NN particle)) (VP (VBZ is) (VP (VBN seen) (PP (IN in) (NP (DT the) (NN receptor) (NN volume))))))))))))))))))) (. .)))
This effect on plume concentration could best be modeled with a particle trajectory model, since these models estimate the concentration at a receptor by counting the number of times a particle is seen in the receptor volume.
(ROOT (S (NP (NP (DT The) (NN number)) (PP (IN of) (NP (NP (NNS particles)) (PP (IN of) (NP (NP (DT a) (NN substance)) (PP (IN in) (NP (DT a) (VBN given) (NN volume)))))))) (VP (VBZ is) (VP (VBN known) (PP (IN as) (NP (DT the) (NN concentration))))) (. .)))