Acceptable indoor air quality is a concern for the comfort and health of humans, in which the 40?70% of relative humidity (RH) is comfortable for the human body and the existence of volatile organic compounds (VOCs) may be harmful for our health. Therefore, the development of wearable sensors that can monitor the RH and VOCs in real time is highly desired. In this work, a mixture of conductive carbon black and exfoliated graphene was dip-coated on fifilter paper to easily fabricate a paperbased flflexible sensor, which can detect RH in the range of 33?95% and VOCs including methanol (MeOH), ethanol (EtOH), toluene (PhMe), dichloromethane (DCM), acetone, and petroleum ether (PE) with relatively short response time. The device can be used to monitor the indoor RH and human breath under various conditions. It also can work as a sensitive and quick-response alarm for the VOC exposure. Furthermore, this flflexible sensor is disposable by ultrasonic treatment without producing hazardous residues, thus considered as an environment-friendly electronic. This versatile and green flflexible electronic device may fifind applications in wearable air monitoring devices and health care.