ODHAD HLUKOVÉHO UKAZATELE Ldvn NA ZÁKLADĚ UKAZATELE Ldn PRO HLUK ZE SILNIČNÍ DOPRAVY V PODMÍNKÁCH ČESKÉ REPUBLIKY.

Objective: Noise indicator Lden is used in Health Risk Assessment (HRA) to estimate noise effects using dose-effect relationships. Determination of its value is often impossible due to the unavailability of noise data in the evening. The aim of this paper is to propose estimation methods for noise indicator Lden based on Ldn indicator for road traffic in the conditions of the Czech Republic and to determine the uncertainties of this estimation.Methodology: A total of 217 individual 24-hour road traffic noise measurements were analysed. They were obtained within the framework of the activities of Czech National Institute of Public Health and Public Health Institute Ostrava. The median of calculated values of the difference between noise indicators Lden and Ldn for individual measuring (the coefficient k) is used to estimate indicator Lden according to the formula: Lden ≅ Ldn + k.Results: The coefficient for the whole data set k = 0.6 and subcoefficients k1, k2 and k3 depending on the difference LAeq,16h - LAeq,8h were calculated. The uncertainties of the estimates are expressed by 95% confidence intervals.Conclusion: It is recommended to estimate noise indicator Lden for road traffic by adding coefficient k = 0.6 to the values of indicator Ldn, or alternatively coefficients k1 = 0.5 (for LAeq,16h - LAeq,8h < 5 dB), or k3 = 0.7 (for LAeq,16h - LAeq,8h ≥ 8 dB) can also be used. Coefficient k2 (for LAeq,16h - LAeq,8h between 5 and 7,9 dB) is identical to coefficient k for the whole data set. The estimate can only be used after an evaluation of the local situation if a smooth pattern of sound pressure levels is expected during 24 hours with the decrease of daytime values towards night-time values and without fluctuations due to local impacts. [ABSTRACT FROM AUTHOR]