Houseplants & Indoor Air Quality

Houseplants & Indoor Air Quality
Houseplants can brighten a room and make it more inviting, but can they actually "clean" the air? As you'll see, the real story behind the connection between plants and air pollution is complicated. 
Most of the online speculation around this connection mentions a 1989 NASA study conducted to research ways to clean air in space stations. This NASA study showed that plants did clean the air in a closed, limited environment or chamber. Other studies have confirmed that plants can remove harmful gases, such as formaldehyde, volatile organic compounds, or VOCs, which have a long history of health impacts. So why don't we all use more green plants to remove pollution?
The problem is that our indoor environments are different from space stations. What works in a chamber study does not necessarily translate into real-life settings. 
One difference results from scaling up from a test chamber to real life. The sample sizes used in testing, such as in the NASA study, are often tiny, so their findings translate poorly into real-world experiences. As a reviewer from the U.S. Environmental Protection Agency explained in a 1992 memo on the NASA study, " achieving the same pollutant removal rate reached in the NASA chamber study" would require "680 plants in a typical house." The memo also said it was "hardly surprising that the attempt to validate the test chamber results by Associated Landscape Contractors of America did not provide measurable success." 
Different plant species, soil types, lighting, temperature, and size can all vary the impact of plants on air pollution. For example, the sunlight or temperature in a room can make some plants absorb more or less pollution.
What is more, plants may even contribute to unhealthy air conditions. Some plants may release VOCs into the air.4 The soil may have bacteria, pesticides, or other contaminants. 
While plants can be beneficial, the evidence does not show they are effective in reducing air pollution. A 2014 review of the research in scores of studies found mixed evidence in real-world studies for improved indoor air quality. Using plants to clean the air in complex places like homes and offices needs much more study.
The bottom line? Don't expect your fern to solve any indoor air problems you have. Scientists continue to study the connection between plants and air pollution, and sometimes, plants effectively reduce air pollution in laboratories. But even if they help, there are better solutions than adding plants to clean indoor air.