The urban activities within areas characterised as densely populated and by high traffic intensity can lead to a situation of air pollution in cities with important harmful effects on human health and the environment. The EU establishes, in this sense, a regulatory framework to control and improve air quality levels in cities (Directive 2008/50/EC). The aim of this work is to evaluate the air quality reported by the official fixed stations with the installation of complementary mobile network of air quality based on passive dosimetry of NO2 measurement during the period 2017-2019. The methodology is applied in Valencia (Spain) as case study, being a representative European middle-size city. The results obtained show that 43.7% of mobile sensors in Valencia exceeded the limit value established by the EU Directive as well as by the World Health Organization (WHO) during the assessment period. Specifically, the results show that 34.6% of citizens live in areas with an average annual value above the limit recommended for the protection of human health. 

Edgar Lorenzo-Sáez, Jose-Vicente Oliver-Villanueva, Lenin-Guillermo Lemus-Zúñiga, Eloina Coll-Aliaga, Carolina Perpiñá Castillo and Carlo Lavalle