Humans are affected most by water pollution because everyone needs to drink water but some of the untreated water carries diseases that can kill someone or make them really sick
Humans are affected most by air pollution because smog causes us to breathe bad air, acid rain pollutes water, and causes damage to agriculture so our food supply would be low.
Humans are affected most by Land pollution because the soil is contaminated with pollutants and this affects the plants grown for food. It can make humans sick or some of the toxins can cause cancer.