Tropospheric Ozone
Tropospheric Ozone
Measurements were commenced early this year at Nyírjés, in April at Hortobágy, in June at Farkasfa, while at K-puszta, they were begun in 1990. The annual ozone variation, with a summer maximum and a winter minimum, is shown by the figure. According to the results of the trend analysis performed on the data, the concentration of ground ozone exhibits a slightly declining trend, on average, per annum.
Figure 3 shows the annual figures for each station, which were calculated on the basis of monthly averages. It can be seen in the table that the monthly averages of ozone concentration were quite similar in K-puszta and Hortobágy. Slightly higher values were measured in Farkasfa than at the other stations, which correlates with the fact that the highest tropospheric ozone concentration in Europe – under background conditions – was measured at a nearby monitoring station in Austria (Illmitz). The amplitude of the Nyírjés plot was lower than those of the other three stations. The summer maximum in Nyírjés was somewhat lower, while the winter minimum was higher than at the other stations.
Exceeded limits for daily averages and 30minute averages were also examined at all four stations. The limits ware 50 ppb and 75 ppb for daily and half-hour averages, respectively. The daily averages exceeded the 50 ppb limit most often in Farkasfa (in 26% of the cases, on 54 days). For the other three stations, this proportion is a much lower 6-8%. According to the analysis performed on the basis of 30-minute averages, the ozone concentration exceeded the 75 ppb limit quite often in the summer months, though there were days in the winter months, too, when limits were exceeded. It is interesting that the
30minute average concentration exceeded the
75 ppb limit in 33 instances in K-puszta in February 1996. The number of times the 100 ppb limit was exceeded by the 30-minute averages was also examined. No values exceeding
100 ppb were recorded in Hortobágy. Such was the case in Farkasfa and K-puszta. Thirty-minute concentration values exceeding 100 ppb were recorded on sixteen occasions in K-puszta in June, while in Farkasfa, 30-minute values over 100 ppb occurred even in June, July and August. Such high concentrations were measured in 78 instances in June, seven instances in July, and on one occasion in August.
30minute average concentration exceeded the
75 ppb limit in 33 instances in K-puszta in February 1996. The number of times the 100 ppb limit was exceeded by the 30-minute averages was also examined. No values exceeding
100 ppb were recorded in Hortobágy. Such was the case in Farkasfa and K-puszta. Thirty-minute concentration values exceeding 100 ppb were recorded on sixteen occasions in K-puszta in June, while in Farkasfa, 30-minute values over 100 ppb occurred even in June, July and August. Such high concentrations were measured in 78 instances in June, seven instances in July, and on one occasion in August.
