While air pollutants have negative effects on plants, such as causing leaf browning and slowing growth, plants can have a positive effect on air pollution. Plants breathe in carbon dioxide, which is a big pollutant, and emit oxygen. They also absorb other air pollutants, such as ozone, carbon monoxide, sulfur dioxide and nitrogen oxides, according to the Colorado State University at Boulder.
Trees and other plants cool buildings and people during the hot months of summer by providing protection from the sun. They also cool the air by evapotranspiration, which reduces the need for air conditioning in some areas. Plants also prevent urban areas from becoming heat islands--areas that hold heat in the atmosphere and increase smog--by cooling the air.
Absorb Carbon Dioxide
Humans exhale carbon dioxide and trees absorb it, releasing more oxygen for us to breathe. This helps keep the air clean. On average, a tree can absorb about 141 lbs. of carbon dioxide a year, according to Colorado State University at Boulder.
Besides carbon dioxide, plants also absorb other pollutants, like ozone and carbon monoxide, both of which make up smog. While too much exposure to these air pollutants can damage a tree's health, it also reduces the amount of pollutants in the air.