The United States Postal Service announced today it will conduct a study of its Portsmouth, N.H.-based mail processing facility to determine if its customers would be better served by consolidating some of its operations with facilities in Scarborough or Manchester, N.H.

The area mail processing study comes at a time when the Postal Service faces one of the most difficult challenges in its history. The current economic downturn and the Internet has led to a 20 percent decline in mail volume since 2007, a situation that has resulted in large deficits.

“As a result of the volume loss, we have more facilities, equipment and people than we need to process a declining volume of mail,” said Deborah C. Essler, district manager for the Northern New England District. “Nationally, we have to reduce the size of our network because we are no longer receiving enough revenue to sustain its cost.”

Essler said one way to handle the problem is to consolidate operations where it makes sense to do so.

Tom Rizzo, a spokesman for the Postal Service in Portland, said the study should be completed by June. It may conclude that mail processed in New Hampshire could be more efficiently handled at the Southern Maine Processing and Distribution Center in Scarborough.

Postal officials say that any changes made in the future will appear seamless to customers.