16. Quantitative CO2 emissions from in closed room with and without air conditioner

Abstract

Indoor CO₂ is produced by the respiration of humans, animals, and plants living in those places. Over time, CO₂ accumulates in the room, increasing its concentration. To study CO2 accumulation in closed living rooms in urban areas today, the study measured CO2 fluxes in three closed rooms. The measured results showed that the highest CO₂ concentration measured was 1,870 ppm (5 am, PN2), which is higher than the recommended threshold according to TCVN 13521:2022 (1,000 ppm). The rate of CO₂ increase depends on room characteristics, sleep duration, and the number of people in the room, with the average CO₂ emission rate being 15.74 ± 3,31 %/hour. The largest volume of CO₂ emitted by a person during an 8-night stay was 66.59 L, which is equivalent to 78.34 L of O₂ required for respiration (~374 L of fresh air). The study showed that with and without using air conditioning, there are no differences in CO₂ emission concentration (P = 0.237). The study results also showed that ventilation is a very important factor that needs to be considered when designing and using air conditioning in buildings.