Phytoremediation of indoor air: Mechanisms of pollutant translocation and biodegradation

The built indoor environment, including domestic housing and commercial offices, has significantly lower air quality relative to ambient outdoor air. Methods of air purification typically rely on traditional mechanical filtration methods such as heating, ventilation and air conditioning systems, which are energetically intensive and require routine maintenance to ensure adequate filtration. To reduce energy demands and to improve urban sustainability, phytoremediation technologies have emerged as a promising method for the remediation of indoor air quality. Due to the need to identify and optimize sustainable methods to improve air quality, we present a comprehensive review on the mechanisms for plant-driven and microbial-driven removal of gaseous contaminants (i.e. volatile organic compounds) is warranted. The literature indicates that indoor air phytoremediation systems rely on complex of both the biological aspects (plant parts, substrate, microbial community, substrate moisture) and abiotic factors (airflow and moisture content), however it is evident that the method for optimal application of these factors within systems is currently significantly understudied, especially in relation to research done in-situ. The authors recommend future research directions should be targeted at plant biochemical analysis of phytoremediation systems exposed to real world pollutants like petroleum vapor, vehicle emissions, and mixed synthetic furnishings of-gassing, as well as the dynamics of the substrate microbial community within root systems. The assessment and developed understanding of these key areas are not only essential for the progression of the field of research but also for continued wide spread adoption for these phytoremediation systems.