(HCHO<0.08mg/m³ and TVOC<0.262mg/m³ refers to good air quality（Good). HCHO is between 0.08-0.2mg/m³, TVOC is between 0.262- 0.650mg/m³, refers to slight air pollution. (Unhealthy). (Hazardous). TVOC detection principle: thick film semiconductor gas sensor.
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