Performance assessment of TVOC sensors used in consumer-grade air quality monitors

Indoor Air Quality (IAQ) has a direct impact on overall occupant health, especially respiratory and neural health. To ensure adequate indoor air quality, we must monitor the air by regularly sampling for pollutants of concern. One important category of air pollutants is VOCs: Volatile Organic Compounds. Some VOCs may be toxic at low concentrations while others require prolonged exposure at high concentrations to become a concern. Traditionally, measuring VOCs accurately has been prohibitively expensive and/or complicated. Recently, consumer-grade air quality monitors have been advertised as affordable counter parts to the expensive and complicated research-grade monitors and sensors. We studied the performance of a unique category of Total Volatile Organic Compounds sensor called a CMOS sensor. We assessed the performance of two brands of TVOC sensors used in three consumer-grade air quality monitors. We conducted a total of 5 experiments, 3 in a real home environment and 2 in a laboratory setting using a state-of-the-art air quality sampling device called the Vocus PTR-Tof. The consumer grade devices tend to exhibit some degree of uniformity in their patterns in response to pollution events, however, they can often deviate from one another in measuring actual concentration levels. The CMOS sensors studied suffer from a range of persistent challenges inherent to the CMOS technology, such as sensitivity and selectivity limitations. While improvements continue, more research is required to determine the extent to which these sensors may be useful and whether they can reliably and reasonably be used to assess indoor air quality