Carbon dioxide(CO2) is acidic gases. It cause irritation to our respiratory system and eyes. It also dissolves in rain water and produce acid rain. Then it kills trees and makes soil and water in lakes and rivers acidic. Habitats of many organisms are then destoryed. Some aquatic lifes many also be killed. this affects their populations and upsets the ecosystems. Beside, acid rain attacks and damage the man-made materials such as stoneworks and bulidings.