I'll second the California Air (8gal?). I had one for a while before I stepped up to a 60 gallon. The CA was surprisingly quiet. I believe from the factory it was advertised as around 75db? Which is probably quieter than most air guns at 100psi.
You may want to regulate the pressure down to like 40 or 60psi for air blowing, if noise is a consideration. And get one of those cone-shaped OSHA blowers, they are reasonably quiet (probably still louder than 75db though, at 90-100psi?)
I replace the air filter with a better muffler and removed the plastic guards, and it got quieter.
I bet building a box around it with 120mm computer fans for venting hot air and bringing fresh air in, and it would be VERY quiet.
I don't know if a 1gallon compressor would give you much air time, I bet it would start to noticeably loose pressure pretty much as soon as you start cleaning up. At least with the 8 gallon you'll get a minute or two of decent pressure before clicking on. Depends on how much air you need.
If there is no DB rating on the compressor, I would probably just go ahead and assume it's loud
