## 4 Conclusions  
Low-frequency noise is ubiquitous in modern society, yet existing legislation in this area is insufficient. Not only is this noise expressed in units of dB(A), which does not reflect the assessment of LFN, but also, no specific measures are prescribed in cases of the identification of excessive LFN. Responses to complaints about LFN at workplaces have not been extensively documented in the literature [20; 31; 43]. Multiple factors, such as noise characteristics, health effects, and employee perceptions, need to be considered when assessing health concerns related to LFN. The aim of this article was to propose the CMARA method (complex method for assessing acoustic risk at low frequencies) for assessing acoustic risk at low frequencies.  
The CMARA method was developed by modifying the risk assessment methods in accordance with Directive 89/391/EEC. Specifically, a Z-weighting method is applied to evaluate the noise levels at low frequencies. These risks draw attention to the need to address the issue of evaluation and measurement of LFN when working indoors. Measurements are necessary to assess the negative effects of noise and to establish permissible values (criteria) that negatively affect health, comfort, and performance. Quantitative measurement of workers' exposure to noise during work are carried out for the purpose of assessing the health risk of exposure to noise and assigning the work to a category.  
An important part of any acoustic risk management is the introduction of appropriate criteria to determine a favorable solution to noise problems. The results indicate that the proposed method can estimate the acoustic risk for these tasks with a long LFN exposure time. For example, it can be seen on the graph (Figure 5) that the impact of the acoustic energy measured for WA2 and WA3 activities using the \(L_{\mathrm{Z}}\) measurement is higher at low frequencies. Such measurements take into account not only the frequency of the sound but also its energy or acoustic pressure, which propagates from the sound source via acoustic waves. Using the CMARA risk assessment, a high risk of adverse non-auditory effects was identified. However, research in this area is also ongoing, and the method used to measure noise is evolving.  
The authors' measurements have already taken place, where non-auditory effects were detected based on heart rate. Currently, further measurements are taking place with the help of medical personnel based on objective medical results. The aim of this study is to highlight the issue of LFN at workplaces based on its assessment using the CMARA method proposed by the authors.  
Management and methodology, writing and final review, M.B.; statistical application and validation, M.B. and H.P.; development of methodology, M.B. and M.T.; data collection and final review of the paper, M.B.; research, data collection, M.B., H.P. and M.T. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
Data Availability Statement: Data are contained within the article.  
This contribution is the result of the project implementation: APVV No. 19-0367 \"Framework of the Integrated Process Safety Management Approach for the Intelligent Enterprise\".  
The authors declare no conflict of interest.