Experimental investigation on the purification performance of particle and planktonic bacteria in the human body micro-environment using low-temperature plasma

Airborne infectious disease transmission in the built environment has caused casualty to people's life. To minimize the inhalation risk of bioaerosol in the human body micro-environment, a wearable low-temperature plasma (LTP) device was developed. The gas fractions produced by the device were studied by the optical emission spectroscopy. The sterilization performance on E. coli and S. albus at different treatment times was investigated. Meanwhile, the purification efficiency of particle and planktonic bacteria in a confined indoor space was also investigated by combining the wearable device with a thermal manikin. Results demonstrated that N₂(B³П_g→A³Σ_u ⁺) and ·OH were the main active species. The concentration of E. coli and S. albus could be reduced from 0.05 to 0.92 log units after treatment by LTP sterilized species. Besides, the particle removal efficiency of LTP on the thermal manikin ranges from 12.55% to 36.37%. By combination of the LTP device and the indoor air cleaners (ACs), the particle cleaning efficiency in the breathing zone of people can be significantly improved. Compared with the natural settlement scenario, the purification efficiency of the planktonic bacteria by the LTP device could reach 24.96%. This study shows that LTP technology can be used as a complementary tool to the current HVAC technology for protection of occupant's breathing air in the human body micro-environment.