To reduce the exposure to air pollution, indoor and outdoor one can check the quality of air at his location. To reduce inside or indoor one should clean the house frequently to avoid the growth of mold or prevent dust in the house.
For outdoor, using cars, bikes, and other fuel-based transport vehicles can lead to an increase in air pollution so one should use walking or mechanical transport means. Industrialized chimneys produce harmful carbon and nitrogen gases which should be limited to reduce.
A peer is someone who is the same age as you, and they do not have to even know you. You might be friends, you might not. They might be a student that's in the same grade as you.
basically, a peer is a student that is around your age.