The respiratory system (mouth, nose, throat, branching airways and lungs) plays a vital role in maintaining a healthy body in that it provides air (oxygen) to every living cell and at the same time removes carbon dioxide (a waste product).

The circulatory system (heart and blood vessels) carries oxygen in the bloodstream to cells and takes carbon dioxide away back to the lungs where it is expelled.
The upper respiratory system (nose and throat) can be affected by a variety of disorders such as nosebleeds and laryngitis.

The lower part of the respiratory system (trachea, bronchi and the lungs) can be affected by dust, infections and smoke, which can cause coughs and asthma. Lung cancer is one of the most common types of cancer in Ireland and indeed the world and is almost always caused by smoking.

Some people find city living or working conditions aggravates their respiratory system and, once removed from the pollutants they feel much better. Similarly with smokers, once they have given up the habit they notice their breathing is much easier and they generally feel healthier.
If you have a persistent cough or are having difficulty breathing see your Doctor as soon as possible.