A headache at work may result from a "sick building" Poor ventilation, mold, finishing materials and polluted air can cause fatigue, breathing problems and worsening of allergies, doctor Marit Mohina told the section. According to her, such situations are especially difficult for people with asthma, chronic runny nose and a tendency to allergic reactions. The expert advises to check ventilation, humidity levels, condition of furniture and decoration, and install an air purifier if necessary.