Headache everyday

I wake up with headache everyday, i ain't sure the reason but according to my neighbor, the headache is caused by the tightness close of window which leads to poor ventilation. Actually i prefer to have window wide open during our rest time, however, the air outside is bad and even harmful to my kids' respiratory system.

I will get myself a dehumidifier if i still have persistent headache, and actually it is great to provide a clean and fresh air for my kids too!