APP is mainly used in combination with the on-board air monitoring purifier HMS04, which can read the values of PM2.5 and carbon dioxide in the air in the car in real time, effectively guide drivers to carry out ventilation operation in the car in time, ensure the health of people in the car, and serve as a reference for replacing air-conditioning filter elements. It can remotely control the start and stop of negative ions and ozone, realize the timing control of ozone generator, and purify the air in the car.