The evaluation and observation of air quality trends in air pollution is crucial to understand the effectiveness and efficiency of air protection measures, to quantify emission factors, to determine standards and to support decision makers in their actions. Due to their reliability, cost effectiveness and power free and light weight installation passive samplers are an important and cost effective tool to identify and follow such air pollution trends.

LEFT: NO₂ pollution decrease in the city of Aarau in Switzerland over a 9 year period.

RIGHT: NO₂ pollution decrease in the city of Baden, located in a mountain valley. Therefore, stable weather patterns as well as traffic impacts are dominating the pollution levels.