In 1989, NASA launched a Clean Air study to determine which household plants are best at purifying the air. As the research has shown, indoor air contains a large number of harmful chemicals, like benzene, trichloroethylene, ammonia and more. But NASA scientists claim that common indoor plants may provide a valuable weapon in the fight against rising levels of indoor air pollution. Some of them can absorb up to 85% of potentially harmful gases, cleaning the air inside our homes, indoor public spaces and office buildings.