Answer: D. Increased illnesses that result in a decrease in population
A decrease in air quality becomes very detrimental to health and as such can lead to a decrease in population. Poor air quality is capable of irritating the eyes, throat, and nose. It also causes shortness of breath and is known to provoke asthma together with other respiratory conditions. Breathing polluted air for long periods of time can cause more serious problems. Both short and long-term exposure to polluted air has been associated with very severe illnesses. Even more severe impacts affect people already ill. According to studies, people who live in industrial areas exposed constantly to polluted air are very likely to have shortened lifespans.