With help of my colleague Dagmawi Matewos, I have installed two measurement boxes filled with instruments in the university campus kitchen. In my courses and research I use low-cost measurement instruments, for which the lower costs usually comes at a cost of quality. Validation is therefore important. We installed the instruments in this kitchen to validate the instruments under high and variable concentration circumstances. In this kitchen, food is prepared for students at various fire pits.
The following instruments are installed across two boxes:
- Four self-developed PM2.5 sensor systems (ASPM);
- Six UCB-PATS+ PM2.5 sampling instruments;
- Ten IQAir Airvisual Pro instruments (measuring PM2.5 and CO2);
- Ten Lascar EL-USB_CO carbon monoxide sensors;
- Three UPAS gravimetric PM2.5 sampling instruments.
All PM2.5 measurements will be compared with each other. The ASPM, PATS and IQAV measure continuously (at a frequency of <20 seconds). The UPAS instrument is used to collect filters for gravimetric analysis, and can be considered as golden standard for PM2.5 measurements. Hence, instruments can be evaluated based on intra-correlation (how well do they compare to their own type), inter-correlation amongst low-cost sensor types (comparing ASPM with PATS and IQAV, and vice versa), and correlation to the reference (UPAS).
For CO2 and CO I only have one instrument, so for those there is only intra-comparison possible. We have installed an additional six IQAV instruments in a student dormitory, to specifically test the instrument under varying CO2 concentrations.