Some Chelsea residents are fighting plans for a new luxury 20-story condominium-hotel project on 15th Street, between Fifth and Sixth avenues, saying it would shift the composition of the neighborhood to commercial from residential, increase traffic and noise, and reduce air quality.

The developer, Tishman Realty Corporation, acquired the additional air rights for the project from neighboring Xavier High School, and Community Board 5 passed a resolution last month approving the deal, but some neighbors say they were never consulted.

“We are seriously concerned that our community board has recommended this project for approval without a full and thorough environmental assessment,” the management of a neighboring cooperative apartment building, Chelsea Lane, said in a letter distributed to residents.

The Chelsea Lane letter was first reported by a real estate Web log, Curbed.

Complicating matters for residents who oppose the project is the development’s “as of right” status, which exempts it from the city’s land use review process. Community Board 5 had no oversight on the project because it was “as of right,” the board’s district manager, Wally Rubin, said.

According to a permit filed with the Department of Buildings, the architectural firm Acheson Doyle Partners is attached to design the project. A spokesman for Acheson Doyle was unavailable for comment yesterday.

The vice president for advancement and alumni relations at Xavier High School, Joseph Gorski, confirmed that an air rights deal had been reached but declined further comment.

A spokesman for Tishman Realty Corporation, Richard Kielar, confirmed the company’s involvement in the project but declined to provide any details.