A low-cost particle counter and signal processing method for indoor air pollution

Indoor air quality is closely linked with respiratory and cardiovascular health, prompting a need for affordable home air quality monitors. The newly- developed Speck is a very-low-cost indoor monitor for measuring fine particulate matter using optical sensors and a unique data processing algorithm. In this paper, we examine the performance of the Speck alongside two professional handheld particle counters (one HHPC-6 and one HHPC-6+) in household environments during cooking events and incense burning events. We demonstrate r(2) correlation values during the cooking event of greater than 0.98 between each pair of Specks and greater than 0.92 between each Speckand 2 mu mparticlecounts fromthe HHPC6/6+ monitors. The error between the Specks and the HHPC-6+2 mu m channel is less than the error between the HHPC-6 and HHPC-6+2 mu m channels. The incense test yielded weaker correlation values, possibly due to uneven distribution of the smoke across the test setup. The distribution of particle sizes appears to be approximately the same as that generated from cooking. We conclude from these experiments that the Speck exhibits a strong correlation with professional particle counters, and that the error between the Speck and one professional unit is comparable to or less than the error between two very similar professional units.