WHAT IS THE MAIN IDEA OF THIS PASSAGE? Acid rain is a result of air pollution. It is formed when gases are released and combine with water in the atmosphere to form an acid. The airborne acids eventually fall to earth in the form of acid rain. Acid rain damages the soil by making it acidic, causing tree growth to slow. Acid rain can pollute water and poison plants. In addition, it can burn holes in the waxy coating on tree leaves and needles, causing photosynthesis to slow. The trees become more vulnerable to disease and insect damage