Observed air pollution specifics of the valley-based towns in Hungary
There are 21 valley-based towns in the 100 most populated ones of Hungary. This topographical feature may be advantageous due to mezoscale circulation between the valley or basin, containing these settlements and the surrounding hills. On the other hand, the hills form a mechanical obstacle that may limit the vertical mixing of pollution. Final result of these counteracting features are analysed by comparing air pollution characteristics of these settlements with those in two control groups, also counting 21-21 non-valley towns of the country. One control-group is selected in accordance with the equal distribution of these valley-based towns, whereas the second group of 21 towns does not consider their location within the country, but they include the most populated towns that do not belong to the previous two groups. Each group represents slightly over 1 million inhabitants. Five air pollution data of eight years (2006-2013), i.e. nitrogen-dioxide (NO2), sulphur-dioxide (SO2), ozone (O3), carbon-monoxide (CO) and large particulate matter (PM10) concentrations are compared. Annual mean, maxima and median values are analysed. The investigation is still in process. The results will also be compared to several economical and communal parameters obtained for three years of the investigated period (2007, 2010 and 2013) to explain the results also with industrial and traffic characteristics, in turn also partly related to the complex conditions of towns located in a valley. The paper is terminated by a collection of valley-based towns in Central Europe counting more than 50,000 inhabitants.