Low-cost air pollution sensors could greatly expand monitoring, but their readings are often affected by environmental conditions. We studied how to improve their accuracy by comparing them with high-quality instruments and using machine learning methods to correct the data. We found that reliable results can be achieved while reducing the time needed for calibration from about 70 % to 80 % of measurements to about 22 % percent, lowering costs while maintaining data quality.

A small fraction of aerosols acts as cloud nuclei and influences climate, yet their transformation remains unclear. Field measurements in Cyprus show that nanometer-sized particles rapidly shrink without prior new particle formation. The shrinkage was linked to changing air masses and possibly evaporation of organic vapours. This newly identified nanoparticle sink improves understanding of particle survival and may affect climate predictions.

We evaluate the ability of the Vaisala AQT530 (Air Quality Transmitter) monitors, comprising of low-cost sensors, to detect spatial and temporal differences. Collocated with reference instruments over 19 months in Nicosia, results showed that CO and PM (particulate matter) sensors captured daily, hourly, and monthly spatial trends. NO₂, NO, and O₃ sensors were less reliable due to environmental effects. Still, all sensors tracked monthly temporal variations at the same location, with PM_2.5 showing the strongest agreement with reference data.

A novel charge transfer ionization orthogonal Time-of-Flight Mass Spectrometer (oToF-MS) was field evaluated for the first time during a field campaign at the suburban DEM station in Athens, Greece from May to August 2023 focusing on key ambient Volatile Organic Compounds (VOCs). The results demonstrate the strengths of the new instrument in performing online, real time measurements of ambient VOCs.

In this paper, we investigate the performance of low-cost electrochemical gas sensors. We carried out yearlong measurements at a traffic air quality monitoring station, where the low-cost sensors were collocated with reference instruments and exposed to highly variable environmental conditions with extremely high temperatures and low relative humidity (RH). Sensors provide measurements that exhibit increasing errors and decreasing correlations as temperature increases and RH decreases.