Vol. 123, No. 2 * Pages 135–264 * April - June 2019

The fog not only makes the traffic more difficult, but it is frequently accompanied by increased air pollution. A research program has been started recently to improve our knowledge about fog both in macro and micro scales. In the first part of the research project, analysis of the data collected in the last 60 years has been performed. This database contains information about the visibility and the duration of the reduced visibility at 8 different cities in different regions of Hungary. The climatology of fog in Hungary has been studied in only few research programs, and no comprehensive analysis of the data has been performed. The first results of the data analysis show that the frequency and duration of the mist significantly reduced between the 1980s and 2000s, and the most dramatic reduction occurred in the northeast region of the country. Furthermore, the frequency of fog also dropped in this time period. The most dramatic reduction of the fog and mist events was found in northeastern Hungary, which was one of the most polluted regions in the country until the 90s of the last century. The coincidence of the significant reduction of duration of fog and that of the sulfate emission in NE Hungary supports the hypothesis that there is a strong correlation between the air pollution and the formation of the mist and fog.