Sneezing is a reaction of the body to inflammation or debris inside the nose and respiratory tract. Sometimes the causes of this need to be investigated medically. Talking to your partner's primary care doctor
would be a good way to start.
The most common cause of frequent sneezing is exposure to small particles in the air that provoke the body's natural defense against such things getting into the lungs. If there is a lot of smoke, dust, or other debris in the air then this may be the cause.
The other very common cause of frequent sneezing is allergies. Allergies are an inappropriate reaction of the body to common environmental exposures, such as pets, pollen, and mold. The nasal passages become swollen and irritated and sneezing results. Some minor cases of allergies can be managed with over the counter antihistamines or with irrigation of the nose with saline spray. Occasionally, however, these agents do not work and a stronger medication is required; there are several options available which your doctor can prescribe.
As always, the diagnosis and the management of your particular condition will require a physical examination by your partner's personal physician. Scheduling an office visit with a primary care doctor is advisable.