Air quality has deteriorated across Hungary due to a high concentration of airborne particles, the National Public Health Centre (NNK) said on Thursday. NNK declared air quality to be “dangerous” in Nyíregyháza, Sajószentpéter, Kazincbarcika and Putnok. Air quality has deteriorated to unhealthy levels in Miskolc and Várpalota. Concentrations of particles are also considered to be too high in twelve other cities and towns, including Budapest, NNK said. Forecasts show air quality is expected to improve in most parts of the country over the weekend. NNK advised vulnerable groups such as people suffering from respiratory problems in those cities to spend less time outdoors as the effects of the air pollution level can be dangerous for them.