A predictive correlation between hard cosmic ray flux (HCRF) near the Earth's surface and sudden increases in the number of cases of cardiovascular disease (CVD) was studied in Vilnius city. Gamma spectrometers were used to measure HCRF. Changes in the total number of impulses registered by these devices were taken as the physical parameter for prediction of an increase in the number of CVD cases. For quantitative assessment of CVD dynamics two empirical criteria for HCRF were proposed: (1) a consistent fall in the HCRF by 200 or more impulses for 4 or more hours per day; (2) the difference (no less than 15 impulses per hour) between the average number of impulses registered in 2 (subsequent and previous) days. The periods analyzed were those when the number of CVD cases exceeded the average monthly level by 10% and 15%. HCRF fluctuations were used as an indirect indicator of variations in the geomagnetic field, and a leap in CVD cases was predicted 1-3 days following a change in the HCRF according to the two criteria mentioned above. The predictive reliability of an increase in CVD cases within 2-3 days exceeded 80%, and within 1-2 days 70%. No essential difference in predictive reliability was observed when the number of CVD cases exceeded the average monthly level by 10% or 15%. Geomagnetic field variations contribute only insignificantly to leaps in the number of CVD cases, which are evoked by the sum effects of other factors. The results of the present study should be regarded as preliminary.

The prognostic relationship between a decrease of hard cosmic ray flux (HCRF) and subsequent leaps in cardiovascular disease (CVD) occurrence within 1-3 days is well known. The influence of meteorological situations on human health is also known. However, no correlation was found between a simultaneous decrease of HCRF and atmospheric pressure and the leaps of CVD on some days. For the analysis of a prognostic connection between these parameters, empirical criteria have been put forward. To achieve effective results from analysis, the criteria of a continuous decrease of HCRF to 200 impulses or more within 4 h and of atmospheric pressure by 2 mmHg or more were used. CVD leaps were considered real when their number increased by 10% or more in comparison with the average monthly value. The highest prognostic correlation between HCRF decrease and CVD leaps within 1-2 days was from 64 to 76%. The correlation within 2-3 days was lower. The correlation between atmospheric pressure decrease and leaps of CVD in 1-2 days and on the same day was 25-44%. It means that, while studying the meteorological effects on human organisms, other parameters such as temperature, humidity, wind velocity, etc. should also be taken into account. An essential role in reducing the prognostic accuracy of CVD leaps by a decrease of HCRF relates to the human factor.

Journal of Environmental Engineering and Landscape ManagementPublication details, including instructions for authors and subscription information:Abstract. Analysis of hard cosmic ray flux (HCRF) variation at an energy interval 1.2-1.6 MeV was carried out in Vilnius. Connection between HCRF decrease at the mentioned energy interval and the minimum atmospheric pressure in 3-6 days is defined. This phenomenon is registered from 8 up to 13 hours. According to the time interval of HCRF decrease, for instance 8-9 and 9-10 hours, the minimum pressure in Vilnius takes place in 3-4 days, and at time intervals 11-12, and 12-13 hours -in 5-6 days. Realization of this prognosis at one of the presented time intervals was 56-67% in 2002-2003. The same investigation results, with the assumption of atmospheric pressure decrease from 1005 hPa and less, showed a high efficiency of prognosis of the minimum pressure in Vilnius at all the time intervals during 6 days - 92%, and 82% in 2002 and 2003, correspondingly.

The mechanism of primary cosmic particle transformation into secondary radiation near the ground surface is analysed. It is known that the main part of secondary cosmic radiation consists of muons. They are formed after nuclear reactions between primary protons and the nuclei of atmospheric gases. Maximum muon concentrations are formed at an altitude of 15 km from the ground surface. Because of a short existence time of muons (2 μs), the amount of these particles near the ground surface depends on variations in the altitude of the above‐mentioned atmospheric layer. Therefore, an unstable flux of muons is registered near the ground surface. Their variations are connected with the Sun's radiation instability, geomagnetic field variations, meteorological process changes, etc. Measurements of the hard cosmic radiation component only near the ground surface are carried out. To this purpose protection of the detector of gamma‐spectrometer was improved. Small gaps between lead plates were made to abolish the shower phenomenon caused by cosmic radiation and the effect of weak‐energy particles and as a result to improve the measurement accuracy. It is defined that lead protection of the thickness of 9 cm of the detector fully absorbs muons with 1,6 MeV energy. It is registered that the gamma‐quanta of 1,6 MeV energy of radionuclide 232Th lose 70 % of the initial energy only in the same lead protection. In 2001–2002 a study was made of the course of the hard cosmic ray flux (HCRF) near the ground surface in four energy intervals: 1 ‐ 0,3–1,2 MeV, 2 ‐ 1,2–1,6 MeV, 3 ‐ 1,6—4 MeV, 4–4 MeV and more. Various course of the HCRF in the mentioned intervals is obtained.

Monitoring of the volumetric activity of a radionuclide 137Cs in the coastal waters of the Baltic Sea was carried out near the settlement of Juodkrante in the summer – autumn of 2004. Three measurement stages of the VA of this radionuclide were carried out and hydrometeorological situations were considered simultaneously. 137Cs VA change cyclicity was found out near the seacoast. Extreme data for the whole period of observation were 48 and 94 Bq/m3. Maximal values exceeded minimal data approximately two times, which practically coincided with the radioactive “background”. The method of mathematical modeling was used to find out possible reasons of 137Cs VA change near the sea‐coast. Because of lack of information about the location and power of a possible “source” of radioactive pollution, repeated calculations were carried out, assuming its various places of formation and various power, i e search of optimum coincidence of calculation and measurement data was selected. Optimum coincidence of theoretic and measurement results was found at the location of a radioactive “source” in the southern part of the Lithuanian sea area at a distance of 25–35 km from Juodkrante. The VA of the radioactive “source” was 5000 Bq/m3 in the summertime and 15000 Bq/m3 in October of 2004. Agreement of measurement and calculation results was satisfactory for all the observation stages.