"Exertion or emotional stress can bring on angina, obliging the victim to rest until the pain subsides. If rest does not help, drugs can dilate the blood vessels. As heart disease worsens, angina recurs with less exertion. "
The WHO warns that asairqualityworsenstheriskincreasesfor manydiseases. Theseincludestroke, heartdisease, lung cancer, andbreathingdiseasessuch asasthma.