How do plants primarily help improve air quality?

Plants play a crucial role in improving air quality primarily by absorbing carbon dioxide (CO2) from the atmosphere during the process of photosynthesis. This process not only helps reduce the concentration of carbon dioxide, which is a significant greenhouse gas, but it also facilitates the release of oxygen (O2) as a byproduct. The oxygen produced is essential for the survival of most living organisms on Earth, as it is required for cellular respiration.

This process vastly improves air quality by mitigating the impacts of excessive CO2 levels, which can contribute to climate change and poor air quality. Through their natural growth and metabolic processes, plants act as air purifiers, fostering a healthier environment in which other organisms can thrive.

In contrast, the other options do not accurately reflect the beneficial role of plants in improving air quality. Nitrogen is a major component of the atmosphere, but its release by plants does not contribute positively to air quality. Ozone is beneficial in the upper atmosphere but is a harmful pollutant when produced at ground level. Lastly, plants do not require high levels of pollution to thrive; in fact, many are adversely affected by pollution. Thus, the correct choice emphasizes the essential function of plants in balancing atmospheric gases and enhancing overall air quality.