SEATAC, Wash. -

Passengers at Seattle-Tacoma International Airport could be breathing a little easier thanks to a new network that reduces fuel use by planes waiting at the gate.

The Seattle Times reports that to cool or heat passenger cabins, planes have historically used their own auxiliary power, which burns jet fuel, or relied on diesel generators.

But last month Sea-Tac launched a new "preconditioned air" network, which cools or heats air at a central plant and then pumps it through hoses onto the plane. That means less exhaust hovering over the tarmac.

Fifteen miles of pipes connect the chillers and heaters at Sea-Tac to the gates.

So far, 29 gates are using it, and all 73 gates will supply preconditioned air by the end of this year.

United Airlines' station manager at Sea-Tac, Jonna McGrath, says the system reduces fuel consumption by 40 to 100 gallons each layover because the planes don't have to supply their own energy.