Are greenhouses gasses bad? Is oxygen a pollutant? We know that oxygen is essential for life. So, if the answer to: "Is oxygen a pollutant?" is no, then carbon dioxide is not and cannot be a pollutant as well. Oxygen is produced by plants. To thrive plants need water, soil nutrients, sunlight and carbon dioxide. Some would suggest we need to reduce the carbon dioxide (plant food) in the air. Some say greenhouse gasses are bad.