According to tests from a portable PM2.5 detector, the indoor PM2.5 level in a laboratory was 57.1, while outdoor PM2.5 was 62. The experiment was conducted in a 13-square-meter closed bedroom. Three types of mosquito coils—coil-based, electric mat, and electric liquid—were tested to see if burning a mosquito coil overnight with doors closed would push PM2.5 levels above 500.

Experiment 1: Coil-based mosquito coil. At 9:00, the mosquito coil was lit in a closed room, with the PM2.5 sensor placed 30cm away. From 9:00 to 10:05, PM2.5 was 154.4. Between 11:10 and 11:15, PM2.5 rose slowly to 258.7. At 12:00, one-quarter of the mosquito coil had burned. From 12:00 to 12:05, PM2.5 was 308.7. By 14:30, two-thirds had burned, and PM2.5 reached 417.4. At 16:00, PM2.5 hit 475. At 17:00, the mosquito coil burned out, and indoor PM2.5 was 564.6. This suggests that burning a coil overnight without ventilation can pollute indoor air to severe levels.

Experiment 2: Electric mat mosquito coils and electric liquid mosquito coils. Using the same method and space, both electric mosquito coil products produced far less PM2.5 than the traditional coil. At 16:00, the room with the electric mat recorded PM2.5 at 156.3, while the electric liquid room was 110.9. However, with windows closed, both produced a pungent odor.

Conclusion: Electric mat and liquid mosquito coils produce less PM2.5 than traditional coils, but still generate significant amounts.

PM2.5 is harmful to humans, referring to particles with a diameter up to 2.5 micrometers. These particles can damage lungs and tracheas, affecting overall health.

To mitigate the harm caused by indoor PM2.5, air purifiers can be used. The PM2.5 sensors they use include laser and infrared PM2.5 dust sensors developed by Luftmy.