Plants are known for their ability to convert carbon dioxide into oxygen in a process called photosynthesis, thus creating the basis of life on Earth. But did you know that plants can also help reduce air pollution? Recent studies have shown that plants can be used to purify the air and reduce the amount of toxins in the air. In this article, we'll explore the scientific evidence behind these claims and discuss why plants are an effective way to improve indoor air quality (IAQ).A well-known process carried out by plants is photosynthesis, in which they absorb carbon dioxide and release oxygen. This process is essential for life on Earth, as it helps create the oxygen we need to breathe.
But plants also have another process called respiration, in which they absorb oxygen and release carbon dioxide. According to a much-cited study conducted by NASA, it has been discovered that indoor plants can purify the air and eliminate “up to 87% of the amount of toxins in the air”. However, recent studies have cast doubt on these claims and have found that indoor plants don't actually have a significant effect on improving IAQ. So what is the real scientific evidence behind these claims? To answer this question, we need to look at how plants interact with their environment. Photosynthesis includes the capture of carbon dioxide (CO2) from the air, along with water (H2O) from air and soil, and light energy from the sun to create glucose (sugars) and oxygen (O2). However, it is less well known that plants also return CO2 to the atmosphere through respiration. Cellular respiration is the process by which plants combine O2 with food molecules, retaining the necessary substances and discarding CO2 and water as waste products.
Photosynthesis occurs in the presence of sunlight; in its absence, plants use cellular respiration to survive. The findings of recent studies indicate that the positive effects of plants on indoor air quality are controversial, and if they exist, the intensity of the effect is not so clear. In some cases, it is so small that a room would have to be filled with plants disproportionately to achieve a measurable reduction in certain pollutants. This is an obviously unrealistic and impractical scenario, and would create other problems, such as increasing humidity too much and introducing the danger of mold. For example, citing a study by Gubb et al., five plants would need almost two years to completely remove 40 ppm of NO2 from a room; at the same time, new nitrogen dioxide could enter through ventilation, thus nullifying the effect. There is still research to be done to learn more about how plants can improve IAQ, especially with regard to the ability of individual plant species to clean the air and the environmental conditions that favor or curb this effect. Based on these findings, new systems with significant air-cleaning capabilities could be designed.
According to this research, some scientists claim that indoor plants are effective natural air purifiers. And the bigger and leafier the plant, the better. In a review published on April 19 in Trends in Plant Science, Frederico Brilli, plant physiologist at the Institute for Sustainable Plant Protection of the Italian National Research Council, and his colleagues conclude that better knowledge of plant physiology, together with the integration of intelligent sensor-controlled air cleaning technologies, could improve IAQ in a cost-effective and sustainable way. Vegetation helps cities become better habitats for wildlife and people, and helps make the air in cities safer. And, of course, trees are just one way to filter pollution; it's best to reduce pollutant emissions in the first place. Brilli and her colleagues don't expect plants to replace modern heating, ventilation and air conditioning systems, but they argue that integrating plants with intelligent sensors, networks and other computerized technologies could make these air purifiers more cost-effective and sustainable. The selected plants can also be used as raw materials for the production of energy and bio-based chemicals. And since the direction of the wind and the structure of the landscape can affect how pollution moves, it is necessary to plant trees accordingly.
However, municipalities should be careful when selecting trees for planting; for example, McDonald et al. stopped planting hawthorn after iTree revealed that it was of little help to air quality. McDonald, who works with municipal governments to manage urban forests, says that as a general rule trees should be planted close to where people are (and sources of pollution). Plants that will be used for air phytoremediation have potential to reduce air pollutants and improve air quality; they also fix carbon dioxide through photosynthesis and help reduce greenhouse gases in atmosphere. Plants are often considered to be “the lungs” of an ecosystem because they absorb carbon dioxide and emit oxygen says Rita Baraldi, a plant physiologist at Institute of Bioeconomics of Italian National Research Council. In conclusion, recent studies have shown that planting certain types of plants can help reduce air pollution by absorbing toxins from indoor environments. Plants can also help reduce greenhouse gases in atmosphere by fixing carbon dioxide through photosynthesis.
However it is important to note that reducing pollutant emissions should always be prioritized over planting trees.
