The escalation in population has led to increased urban density owing to the readily available resources facilitated by globalisation. This urbanisation process has solidified the natural topography, displaced indigenous green spaces, and disrupted the equilibrium of the natural ecosystem—a pivotal source of air purification. Additionally, this urbanisation has contributed to a rise in temperature due to the heat-island effect. Despite urban cities encompassing a mere 3% of the Earth’s surface, they accommodate approximately 50% of the global population and are responsible for over 75% of annual worldwide greenhouse gas emissions. Notably, energy production alone contributes at least 55% to these emissions. Within the context of Milan, the prevailing climate change era, a pressing imperative exists to curtail energy consumption, thereby mitigating the adverse impacts of air pollution and carbon emissions on the environment. This research endeavours to devise a retrofitted passive ventilation system tailored for a conventional office building. The inclination for such an undertaking stems from energy consumption; office spaces’ universal thermal climate index is double that of residential spaces. Furthermore, the spaces surrounding office buildings are maximally utilised during office hours, which coincide with peak daytime conditions characterised by elevated humidity and solar radiation. Conversely, these spaces become dormant outside of office hours.

Consequently, this research focuses on developing a retrofitted passive ventilation system designed for a complex of office buildings in Milan, Italy. Milan was selected due to its designation as one of the most polluted cities, specifically in the summer months of each year, characterised by exceptionally high atmospheric pollutant levels (PM 2.5). The envisioned system aims to sequester carbon and passively ventilate the indoor office space by supplying fresh air passively to the existing building’s HVAC system, thereby ameliorating the universal thermal comfort index and reducing overall building energy consumption. This, in turn, contributes to decreasing greenhouse gas emissions from energy production. The system also enhances outdoor thermal comfort and fosters a cultural environment around the buildings, rendering the spaces functional throughout the day. The design of this system is informed by environmental factors and principles of biomimetics, drawing inspiration from termite mounds for the evolution of passive ventilation strategies. Additionally, an agro-based material composition has been formulated, promoting the growth of biofilm that can sequester carbon while emitting fewer carbon emissions compared to conventional building materials.