If you are having some symptoms, you can change your HVAC filter or get an air purifier. However, sometimes your allergy symptoms just do not go away. I usually take an 24 hour antihistamine at night if I am having severe symptoms. The pill usually makes me sleepy so I end up having a good night's sleep. If my symptoms are not that bad, I just keep tissues with me. I also drink honey and lemon tea or honey and lemon in hot water. That usually seems to alleviate minor symptoms.