Beyond Filters: Evaluating Biotechnological Indoor Air Purification with Microalgae Systems

¹ Department of Architecture, Dokuz Eylül University, 35390, İzmir, Türkiye
² Energy Research and Application Center (EUAM), Dokuz Eylül University, 35390, İzmir, Türkiye
³ Department of Bioengineering, Manisa Celal Bayar University, 45140, Manisa, Türkiye
⁴ Department of Environmental Engineering, Dokuz Eylül University, 35390, İzmir, Türkiye
⁵ Electric and Energy Department, İzmir Vocational School, Dokuz Eylül University, 35360, İzmir, Türkiye
⁶ Department of Mechanical Engineering, Dokuz Eylül University, 35390, İzmir, Türkiye

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Abstract

Abstract. Managing indoor air quality is crucial to prevent harmful health impacts on building occupants. Prominent strategies are controlling the source of emissions and pollutants, effective design of ventilation systems, and active reduction technologies. The various air purification methods range from conventional physicochemical techniques to sustainable biological treatments. Among these, biofiltration technologies stand out due to their environmental, economic, and social benefits. Additionally, emerging systems such as microalgae technologies offer carbon capture potential, while also retaining other pollutants, and contribute to improved quality of life, human health, and productivity of occupants. In recent years, while the potential benefits of microalgae on indoor air quality have attracted significant attention. However, the limited scope of existing literature and the need for deeper research into the potential effects of microalgae systems are the motivations of this study. This study evaluates biological air purification systems, particularly microalgae-based technologies, comparing them with conventional mechanical and plant-based approaches. The method is an Excel-based mass balance simulation to model pollutant removal performance for CO₂, VOCs and PM_2.5. The representative environment is an office with 96 m³ air and 15 occupants working over an 8-hour period. The simulation compares four system configurations; 1. Microalgal air purification with Chlorella vulgaris, a green wall, a HEPA filter, and a hybrid system with microalgal air purification and green wall. Results show that microalgal systems achieve superior performance in VOC removal and CO₂ mitigation, reaching steady-state concentrations of ~745 ppm compared to ~834 ppm without treatment. HEPA filters excelled at particulate matter removal (>99.97%) but provided no CO₂ reduction. Results indicate that biological air purification systems offer superior environmental sustainability compared to conventional mechanical approaches, with lower operating costs and multiple co-benefits including oxygen production and biomass generation. Although microalgal air purifiers are not widely used on the market, they stand out as a promising alternative for future air purification technologies due to their lower environmental impact, higher efficiency, and effectiveness across a broader range of pollutants, particularly in sustainable building design. However, pilot-scale studies and standardized evaluations are essential to advance and validate these technologies for widespread adoption.