Duration of Ground Ozone Anomalies in Crimea

Abstract

The purpose of the work is to analyze episodes of exceeding the current World Health Organization criterion for ground-level ozone (MPC 100 μg•m–3 for 8 hours) at the background environmental monitoring station (BSEM) Karadag (Republic of Crimea). Materials and methods. The research area is the Karadag Nature Reserve on the southeastern coast of the Crimean Peninsula on the slope of Mount Svyataya. Information base: average hourly values of ozone concentrations measured using an automatic gas analyzer APOA 370 (HORIBA) at a height of 2 m from the earth's surface, and meteorological data obtained by the weather station "WS – 600" and "TROPOSPHERE – N". The research methodology included summariz- ing and analyzing data for three years (2019-2022). Results and discussion. During the period 2019-2022 98 cases of increase in ground-level ozone concentration (SOC) above 100 μg•m–3 were detected, 30 % of them had a duration of more than 8 hours. The background conditions for the formation of such episodes are considered. The values of meteorological parameters contributing to the prolongation of episodes are assessed. Local and global factors leading to SOC anomalies are studied. Conclusions. Almost all episodes were accompanied by low atmospheric pressure and wind from the Black Sea. It is shown that an increase in SOC is associated with the passage of the cyclones rear parts. Local factors contributing to ozone generation and influencing the duration of ozone episodes may include diffusion of volatile organic compounds from the volcanic surface of the Karadag mountain range, as well as synthesis of hydrocarbons by plant communities of the reserve. Among the global factors, one can note the influence of stratospheric ozone changes and the beginning of solar activity twenty-fifth cycle leading to an increase in periods of SOC anomalies and manifestations of spring maxima over a three-year period.