Brenda Knight (coauthor of Random Acts of Kindness) knows the way to lessen pollution, raise oxygen levels, and provide shade on a sunny day.

Plant a fruit tree. We know trees clean air by absorbing odors and pollutants while also providing oxygen and shade. And if you want to be generous, go ahead and plant a fruit tree near the fence or street. Put up a little sign that says “Help yourself!”
Random Acts of Kindness
365 Days of Good Deeds, Inspired Ideas and Acts of Goodness
The change you want to see in the world. This good-humored guide to being the change you want to see in the world is filled with suggestions for making a real difference, in ways both large and small. From improving someone’s life with just one penny to ensuring all children are well fed, the day-by-day positive proposals of Random Acts of Kindness combine inspiration with action. Despite the hurly-burly of our busy lives, we can all make a beneficial impact on the environment, throughout out local community, and within our own hearts. This book of inspired ideas and good deeds conveys how “the power of one”―that is, you―can make a better world, starting today!