THE BRONX - Officials are beginning to crack down on the landlords with the most air quality violations. 

Mold and cockroach infestations are air quality violations that experts say can be harmful to human health.

State Sen. Jeff Klein describes the apartment complexes with the most air quality violations as "the dirty dozen." 

A third of the buildings on that list are within the Bronx. They include Stevenson Commons and Andrew Plaza Commons.

Klein says that cleaning up the worst buildings will also help reduce the threat of Legionnaires' disease in the borough.