Greenhouse gases emitted by commercial airplanes contribute to global warming and endanger public health and the environment, US officials concluded Monday, opening the path for regulation of passenger planes.

The final assessment by the US Environmental Protection Agency supports the goals of President Barack Obama's plan to reduce emissions from large sources of carbon pollution.

US aircraft are "the single-largest greenhouse gas (GHG)-emitting transportation source not yet subject to GHG standards in the US," said the EPA.

Aircraft are responsible for about three percent of total US GHG emissions.

And US airplanes make up 29 percent of these emissions from all aircraft globally, said the EPA.

"Addressing pollution from aircraft is an important element of US efforts to address climate change," said Janet McCabe, EPA's acting assistant administrator for air and radiation.

"Aircraft are the third-largest contributor to GHG emissions in the US transportation sector, and these emissions are expected to increase in the future," she added.

"EPA has already set effective GHG standards for cars and trucks and any future aircraft engine standards will also provide important climate and public health benefits."

It was necessary for the EPA to make a final determination that risks are posed to the environment in order to begin the regulatory process.

However, Monday's announcement neither proposes nor finalizes any such regulations.

The EPA said the emissions of concern are carbon dioxide (CO2), methane, nitrous oxide, hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6).

The regulations would exclude small tourist aircraft and military airplanes.