The Boston Zoning Commission has approved several amendments to the city’s zoning code that require all new and rehabilitated buildings, exceeding 50,000 sq ft, to qualify for the lowest level of LEED, a green-building rating system of the U.S. Green Building Council. The regulations do not  require property owners to apply for certification. Instead, a LEED-accredited professional on the building team must ensure that the project could achieve certification.