The ion smoke alarm is sensitive to the tiny smoke particles and can respond to various smokes in a balanced manner. The forward photoelectric smoke alarm is sensitive to the slightly larger smoke particles and has poor response to gray smoke and black smoke. some. When a blazing fire occurs, there are more tiny particles of smoke in the air. When smoldering, there will be more smoke particles in the air. If a large amount of tiny particles of smoke is produced after a fire occurs, the ion smoke alarm will alarm first than the photoelectric smoke alarm. The time interval between these two kinds of smoke alarms is not large, but such fires are spreading rapidly. It is recommended to install ion smoke alarms in such places. After the occurrence of another kind of smoldering fire, a large number of slightly larger smoke particles are produced. The photoelectric smoke alarm will alarm first than the ion smoke alarm. Such places are recommended to install photoelectric smoke alarms. If you want to combine the strengths of both, you can install both types of smoke alarms where smoke alarms are required.