It's a breath of fresh air for the city.
Mayor Bloomberg's Office says the city's air is the cleanest it has been in more than 50 years.
The city says greenhouse gas emissions have been reduced by 19 percent since 2005.
The Mayor's Office credits the decrease to expanded air quality programs, including carbon-reduction challenges, increased financing for clean energy and plans to use more natural gas.
The city is on track to reach it's goal of reducing greenhouse gas emissions by a total of 30 percent by 2030.