The pollutant index can be measured of indoors or outdoors by the detector, it could guarantee accuracy 95% or more, give you a healthy living environment. Air pollution, mainly from the haze, dust particles, smoke, car exhaust, second-hand smoke, soot, etc. Air pollution is extremely harmful to the body, this product can detect the air pollution index for you. This item uses laser dust sensor with fast response, high accuracy and good stability. Multi-layer filter anti-interference, anti-false alarm, to prevent other gas interference, PM 2.5 measurement accuracy greatly improved.