Air pollutants that are not greenhouse gases can still affect climate change. They may do this by directly reacting with greenhouse gases or by indirectly affecting greenhouse gas systems. Felzer et al. studied how ozone, a toxic gas produced in polluted air, is and will affect the ability of plants to store carbon and keep it from affecting the climate. While the researchers find increasingly negative effects in the future, they also predict that greenhouse gas reductions would also reduce the amount of ozone in the atmosphere, and its damaging effects.