Which of the following groups of people are most likely at risk for health problems resulting from air pollution?
a.
athletes
b.
young professionals who commute to the city each day
c.
people who live in apartments
d.
people with asthma or other respiratory illnesses

D. People with asthma or other respiratory illnesses.

This is correct because people with these issues struggle a bit more with their immune systems more than others. Their lungs and other respiratory organs can become irritated faster than those of non-asthmatic people and such in that area.