Dear John,
I think air pollution is the most dangerous ecological problem. Air pollution affects people, nature and animals. To my mind, some small but important everyday actions can protect our nature. For example, you may plant trees as many as possible. Trees provide oxygen and clean the air. Also you can reduce waste by recycling it. As for me, I usually try to buy recyclable paper and sustainable products to protect forest. It is better to use a bicycle instead of taking out a car every time, so you'll reduce greenhouse gas emissions. It is really important to take participation in voluntary projects that protect nature. Have you ever participated in such project?
Best wishes,
Alex