Several Hungarian towns and cities are plagued by poor air quality due to a high concentration of PM2.5 airborne particles, the National Public Health Centre (NNK) has said. The air quality in Kazincbarcika, Putnok, Sajószentpéter and Várpalota has deteriorated to unhealthy levels, NNK said. Concentrations of particulate matter are also considered to be too high in Budapest, Esztergom, Győr, Miskolc, Nyíregyháza, Sopron, Szeged, Székesfehérvár and Vác.