What type of transportation is Greyhound to Seattle airport?

I take a bus to Seattle, Washington, I'm in the greyhound. There any type of transport to the airport bus station? As a bus or something? And there's a phone number so you can get calendar? Really do not want have to take a taxi, that's out of my pay scale.

Be sure to check your arrival time. The bus tunnel is not mentioned above open weekends or evenings. It is not open at night. If you need to take the bus during off hours (evening or weekend), walk four blocks and take Bus No. 174, 4th and Stewart. The Greyhound bus station is at 8th and Stewart.

10 minutes of Seattle bus/train rush hour

Construction strategy and schedule: (tunnel supplement) : technical report …