Unlike many older aircraft models that derive cabin air from engine compressors, the 787 utilizes electric compressors. This not only reduces the aircraft’s overall fuel consumption but also minimizes potential contamination from engine oils.
At the heart of the 787’s air conditioning system are two packs that are situated beneath the aircraft’s fuselage. The air first enters the packs where it’s cooled down, and then it is pushed through a series of ducts and distribution points to reach different sections of the aircraft.
Temperature and air quality onboard are paramount for passenger comfort and the 787 allows the passengers to experience a lower cabin altitude compared to other aircraft. This results in higher atmospheric pressure, which can lead to increased oxygen absorption, reducing fatigue and some of the other common discomforts of flying.
The aircraft also boasts of an advanced filtration system. As the air gets circulated, it passes through HEPA (High-Efficiency Particulate Air) filters, which effectively capture a vast majority of airborne particles, including bacteria and viruses. This ensures that the air passengers and crew breathe is of the highest quality. i read about this a while back