The Spain forward has denied reports that suggested he did not want to play for Van Gaal because of the Manchester United manager's difficult relationship with former Barca goalkeeper Victor Valdes and Spain international David de Gea.
Valdes joined United in January but has barely featured for the first team while De Gea has not played for the Red Devils since 29 July after being heavily linked with a move to Real Madrid.
"It's true that I don't like that treatment for my colleagues, especially for Victor, who has been a reference as a team-mate and as a professional," Pedro told Marca. "I don't believe it's fair but it didn't influence my decision.
"I just saw that Manchester didn't take that move forward, that they were taking too long. Chelsea were more decisive."
Pedro did speak at length with former Barca team-mate Valdes before deciding to join Chelsea last month.
"Yes, a lot," he said. "He told me that United was very good and there was a great fan following, that his only problem was the situation with the coach."
When asked if Valdes recommended he not sign for United because of Van Gaal, Pedro said: "Absolutely not.
"He spoke very well of the club. It's a great club but I believe I have made the right choice to join Chelsea, I'm convinced.
"I had an important chat with (Chelsea coach Jose) Mourinho and he said many things that I liked to hear.
"That combined with the possibility to live in London was what made me decide."
Pedro moved to Chelsea on a $45.95 million transfer from Barca and signed a contract with the Blues outfit until June 2019.
"It was tough to leave Barca," he said. "It was a strange feeling as I had been many years at the club.
"At the start of pre-season I told the coach (Luis Enrique) that I had decided to leave. He understood and supported me.
"At Barca it's always difficult to play and I needed continuity.
"I believe I have made the right choice to move to Chelsea, I'm convinced. I have adapted very well. Since my arrival I have felt comfortable working with Mourinho."
Pedro, 28, has started in two Premier League games and scored on his debut in a 3-2 victory over West Bromwich Albion.
"I believe that this is a very good league for me because there are spaces, a lot of counter-attacks," he said. "I hope I can enjoy this marvellous league."
The Tenerife-born player is currently in Madrid training with Spain's squad ahead of EURO 2016 qualifiers against Slovakia and FYR Macedonia.
