I run cool mist humidifier and air purifier at night but i wake up every morning with a headache. do you have any ideas why? thank you

A few ideas: 1) make sure your body is adequately hydrated -- eating salty snacks or drinking alcohol incrases your body's water requirements, which, if they aren't met, can cause morning headaches 2) use HEPA filter in your bedroom and dustmite covers on your mattress and pillow 3) see neurologist if these headaches increase in frequency and/or severity

As an allergist,: I cringe a little when I hear about humidifiers because they are ripe for biofilms (colonization by bacteria and fungi). If it helps you, please clean it thoroughly and regularly with bleach. Sensitivities to fungus can be a cause of chronic rhinitis and it may be your trigger. Other benign causes of morning headaches include snoring/sleep apnea, migraine, grinding teeth/TMJ pain, poor sleep etc