How often are they sneezing? It’s normal for birds to sneeze, sometimes a few times a day.
Are they acting normal otherwise? No labored breathing, brown discharge from the nose, lacking energy, etc?
If there isn't discharge I wouldn't be overly concerned but if you have an annual checkup anytime soon I'd bring it up. My Sun sneezed quite a bit when I first brought her home. It could be air particles, especially if they're molting there will be fluff and such in the air. Do you have an air purifier? And an air humidifier? It could be just general dry skin causing irritation. Make sure they get regular baths.