Phytoremediation as a nature-based solution for air pollution mitigation: a review

Air pollution, intensified by industrialization, urbanization, and deforestation, causes over 8 million premature deaths annually, with over 99% of the global population exposed to unsafe pollutant levels. Conventional mitigation technologies, though effective, are limited by high costs, energy demand, and secondary waste generation, highlighting the need for sustainable alternatives. Phytoremediation, a nature-based solution (NbS), leverages plant physiology and plant-microbe interactions to mitigate airborne pollutants including PM, NOx, SOx, VOCs, CO, heavy metals and GHGs. This review synthesizes findings from 156 peer-reviewed studies (2020-2025), integrating mechanisms, functional traits, innovations, and socio-economic perspectives. Tree species such as Platanus orientalis, Tilia cordata, and Ficus benjamina reduce PM_2.5 loads by up to 25%, while indoor plants like Chlorophytum comosum and Spathiphyllum wallisii lower VOCs by 30-44%. Hyperaccumulators (Brassica juncea, Pteris vittata) achieve over 90% heavy metals in aqueous systems, and engineered green walls cut VOCs by 72.5% and PM_2.5 by 17-25%. Nanoparticle-assisted systems, also aqueous, achieve up to 99.58% cadmium removal. Despite challenges of pollutant specificity, seasonal variability, and biomass management, phytoremediation remains a scalable, low-cost NbS. The novelty of this review lies in integrating recent biological, technological, and policy advances, positioning phytoremediation as a viable pathway for sustainable air quality management.