Assessing the Spatial Distribution of NO2 and Influencing Factors in Urban Areas—Passive Sampling in a Citizen Science Project in Berlin, Germany

Nitrogen dioxide (NO2) is a major air pollutant with diverse impacts on human health and the environment. In urban areas, road traffic main emission source for NO2. Berlin, Germany, network of measurement stations operated by state, fulfilling monitoring requirements set European Union. To get more detailed overview spatial distribution NO2 concentrations in citizen science project allowed collection additional data an increase number sampling sites. Passive samplers (modified Palmes tubes) were distributed to participants collect at site their choice. When returned, analyzed based Griess–Ilosvay reaction spectrophotometric detection. The results confirmed seasonal trend higher winter lower during summer period. Furthermore, spatially monthly averaged observed study period from March 2019 October 2020 good agreement average background concentration. At small scales, tendency decreasing increasing distance roads was observed. Overall, this shows added benefit extensive low-cost measurements across environments complement stationary pollution networks.