Sniffles is mycoplasma, an omnipresent rat and mouse virus which they carry their entire lives. It flares up in times of stress, and can lead to fatal secondary infections. It is likely that respiratory irritants can increase the risk of these infections.
So, rats will sneeze on aspen, pine, or anything else you put them on. The trick is to try to minimize stress, keep things very clean, and avoid excessive fumes.
Frankly, the ammonia from their own urine is likely far more irritating than the volatile oils from pine, as long as the room is well-ventilated. So, changing the bedding frequently is going to make more of a difference than using aspen over pine.
Cedar, however, is viciously toxic.

ASFs aren't closely related to domestic rats and mice. It is not impossible that they either can't contract myco, or it doesn't affect them in the same way that it does Rattus and Mus genus animals.