Plants are the lungs of the earth: they produce the oxygen that makes life possible, add precious moisture, and filter toxins. Houseplants can perform these essential functions in your home or office with the same efficiency as a rainforest in our biosphere.In research designed to create a breathable environment for a NASA lunar habitat, noted scientist Bill Wolverton discovered that houseplants are the best filters of common pollutants, such as ammonia, formaldehyde and benzene - chemicals released by furniture, carpets, building materials and photocopiers and then trapped by closed ventilation, leading to a host of respiratory and allergic problems now called Sick Building Syndrome.Here Dr Wolverton shows you how to grow 50 plants as accessible and trouble-free as the tulip and Boston fern. He rates each plant for its effectiveness in removing various pollutants.Studies show we spend around 80% of our lives indoors which means good indoor air is vital for good health. How to Grow Fresh Air will show you how to purify the environment that has the most impact on you.