Dry cough might be due to numerous causes like it might be due to the infection leading to bronchitis,sinus infection or it might be due to asthma, allergies and chronic exposure to certain factors like cigarette smoking, dust, pollens or due to occupational hazard like inhaling polluted air on regular basis due to air contamination in the place they work. If its a infection, antibiotics and cough suppressants will itself cure it, generally patient will also have sore throat, fever, headaches, generalised weakness etc if that's the case kindly consult a physician for further management. Sometimes People on early stages of asthma can present with this so get it checked. If its allergic, you will see improvement just by avoiding coming in contact with such things, so get a allergic test done to know about things you are allergic. Get the place of your work inspected to know about the pollutants and their acceptable levels and get it corrected. Wear a mask to avoid exposure to dust. Clean the AC, sometimes the it might contain micro-organisms which might cause infection in people with low immunity. Do daily yoga and meditation and go for morning jogging for 30-40mins and brisk walking for 15-20mins to develop stamina. If you are still not satisfied consult a physician.