Charakterisierung von low-cost Messsensoren zur Untersuchung von Luftschadstoffen und meteorologischen Parametern

Kurzfassung

The increasing commercial availability of micro-sensor technology is radically transforming air quality monitoring. Due to their low cost, real-time monitoring of pollutants can be implemented in new spatiotemporal scales. This could help reduce health risks caused by air pollution. The aim of this thesis is to characterize the accuracy of four low-cost sensor models (MS8607, PMSA003I, MICS6814, MQ131) and hence to identify potential application areas. For this purpose, data from two identical sensor sets (so-called MessBoxen) in Limassol, Cyprus were analysed for the period from 15.11.2023 to 21.12.2023. The monitored parameters included PM, NO2, CO, NH3, O3, as well as meteorological parameters (temperature, relative humidity, air pressure). With its generally poor air quality and regular Saharan dust events, Cyprus represents an interesting study area. Using correlation and regression methods, statements were made regarding the relative measurement accuracy of the sensors. Especially the meteorological parameters and PM showed good results. Additionally, for parameters PM, NO2, CO, and O3 the absolute measurement precision was assessed by comparison with a reference station operated by the Department of Labour and Social Insurance Cyprus. An evaluation of each sensor was then conducted based on five quality criteria: long-term stability and repeatability, accuracy and measurement resolution, cross-sensitivity and user-friendliness. A central challenge for all pollutant sensors was their susceptibility to humidity. Cross-sensitivities could be well corrected by applying multiple linear regression, eventually achieving adjustments of R2 > 0.79 for O3 and R2 > 0.60 for NO2 compared to the reference station. PM also reliably reflected concentration minima and maxima with an R2 > 0.44. The sensors appear capable of reliably indicating local pollution hotspots, therefore contributing to environmental medicine. During the observation period, a Saharan dust event was recorded, furthermore the influence of low-pressure systems was evident in several parameters. The transport of sea salt aerosols by land-sea wind circulation and the semi-circadian (12 h) cycle of air pressure were also observed. A particular finding of the thesis are gravity wave signatures, which were regularly detected in the PM and to some extent in the temperature and air pressure data. They were then further investigated in terms of their energy propagation and orientation of wavefronts through additional wind data. It could be demonstrated that smallscale wave signatures could be recorded with PMSA003I (PM) and MS8607 (meteorological parameters) even with minimal modulation. Besides air quality research, this opens up new possibilities for investigating atmospheric dynamics.