Formaldehyde is a common indoor air pollutant that can cause various health problems, such as eye, nose, and throat irritation, asthma, and even cancer. However, most existing sensors for formaldehyde are not sensitive or selective enough to detect low levels of the gas or to distinguish it from other volatile organic compounds (VOCs).
Researchers from the University of Cambridge and Warwick University have developed a novel sensor that can overcome these limitations. The sensor is made from aerogels, ultra-light materials that are sometimes called ‘frozen smoke’ because of their porous structure. By precisely engineering the shape and composition of the pores, the researchers were able to create sensors that can recognize the unique ‘fingerprint’ of formaldehyde at concentrations as low as eight parts per billion (ppb), far below the recommended limit of 100 ppb by the World Health Organization (WHO).
The sensor uses a graphene-based paste to 3D print the aerogel structure, which is then freeze-dried to achieve the desired porosity. The aerogel contains quantum dots, tiny semiconductors that enhance the sensitivity to formaldehyde. The sensor also employs artificial intelligence techniques to analyze the signals from the quantum dots and to identify formaldehyde among other VOCs.
The sensor has several advantages over conventional sensors, such as low power consumption, room temperature operation, and high selectivity. The sensor can also be miniaturized and integrated into wearable devices or smart home systems for real-time, personalized monitoring of indoor air quality.
The following table summarizes the main features and benefits of the ‘frozen smoke’ sensor for formaldehyde detection:
| Feature | Benefit |
|---|---|
| Aerogel structure | Allows gas molecules to easily diffuse and interact with the sensing material |
| Quantum dots | Enhance the sensitivity and produce a distinct signal for formaldehyde |
| Artificial intelligence | Analyzes the signal and distinguishes formaldehyde from other VOCs |
| Low power consumption | Reduces the energy demand and extends the battery life |
| Room temperature operation | Eliminates the need for heating and cooling elements |
| High selectivity | Avoids false alarms and provides accurate information |
| Miniaturization | Enables portable and wearable applications |
The researchers hope that their sensor can help improve the indoor air quality and health of millions of people who are exposed to formaldehyde and other VOCs on a daily basis. They also plan to adapt their sensor to detect other hazardous gases, such as carbon monoxide, nitrogen dioxide, and ozone.
