“…For measurements of the concentration of gaseous air pollutants, low-cost sensors often are used [22], such as the Waveshare MQ-135 [12,20,23] and other sensors of the Waveshare MQ family [23,24], the Bosch BME680 [21,24], the Bosch BME688 [11], and the Sensirion SGP30 [11]. In the case of particulate matter, the PM2.5 is usually measured [18,19,21,[25][26][27], although some systems also measure PM10 [18,19,27,28] and PM1 [27]. For particulate matter measurements, such low-cost sensors as the Alphasense OPC-N2 [27], the Alphasense OPC-N3 [21], and the PMS7003 [28] are used.…”