I was at at major airport (Denver) very little impact on traffic. Your pay should not be affected any airport, you would have to see several years of declining traffic not to hold their pay grade. this is right off historical data. you will note a higher than normal cost of living raise, the gov is trying to stimulate the economy.
also in my opinion, a downgrade would probably be the best thing you could get involved in. pending your current pay is still in the new band.
your next upgrade or new facility would place you in a much higher pay status.
here is a real life example: Den, ATC 12 transfer to LAS, ATC 10 save pay, your pay is still in the band..no state income tax in Nevada, so really a pay raise..transfer back to DEN ATC 12.. two step increase, easy money! if you dont burn bridges you could do this a few times in your career.