# Noise Annoyance in Physical Sciences: Perspective 2015-2024
## 4 Discussion  
Taking into account the results of the analyses presented above, it should first be noted that there are no statistically significant differences in the distribution of publications between the periods 2015-2019 and 2020-2024. Despite quantitative variations, the calculation of the chi-square coefficient clearly indicated a lack of such relationships. It is also worth noting that, regardless of the time period, the largest proportion of the analyzed publications were scientific articles published in journals, accounting for 65.18% of all works examined. This may be related to the faster publication process offered by scientific journals--such as through special issues--which is particularly important given the time-sensitivity (e.g., potential obsolescence) of research findings, especially in the context of experimental methods and survey-based studies. A similar explanation would apply to the decline in the publication of chapters in books (Figure 3). A total of 90% of them were theoretical (10% were survey-based articles). As the interest in experimentation and practical research increases, the interest in conceptual works drops down. This is a natural trend of research, where theoretical preparation precedes practical research. The necessity of relatively quick publication may also explain the full convergence of the percentage of publications using the experimental method (65.18%) with the number of scientific articles (65.18%), especially since the experimental method was used in a wide range of topics of the analyzed publications. The most works used an experiment in research on Road Transport with 30.36% of all publications. They concerned both the inconvenience of road noise [20] and the direct impact on people's health [65]. This shows the possibilities of a wide application of the indicated research method. It served both as a tool for drawing theoretical conclusions [17], as well as studying perception [67], or modeling aircraft engineering [110]. Therefore, it is not related to the specificity of any research category or subcategory. It is also worth noting that the number of publications in the engineering area increased by 66.67% compared to the years 2015-2019 while the other categories decreased (Figure 4). The recorded increase can be connected to an increase in the use of the experimental method and a decrease in the conceptual method. Engineering, as an applied science, naturally uses the tools of experimental methods. Additionally, an experiment was considered as an issue in articles in which researchers independently measured noise. Measurements are most often made as part of engineering. Additionally, the largest number of publications was recorded in Road Transport--57 (50.89% of all publications in the years 2015-2024), Urban Noise--45 (40.18%), and Air Transport--38 (33.93%). Considering that engineering mainly concerns Air Transport (47.91% of publications in this category) and Urban Noise (31.25% of this category), the findings may indicate the current demand for articles from the engineering area, primarily in the field of Road Transport. This conclusion corresponds to the finding of a high level of saturation of the Environmental Science category indicated by the topics Road Transport--45 (40.17% of all) and Urban Noise--31 (27.69%). It therefore seems that the revealed trend indicates the potential development of engineering in the Road Transport area. In the Energy category, there were no publications in the scope of Rail Transport. Similarly, zero publications appeared in the Earth and Planetary Sciences category in the areas of Rail Transport and Renewable Energy. This again highlights research gaps in these specific areas, particularly related to noise generated by Rail Transport. This is notable, especially considering that the primary research focus within Rail Transport has been on noise nuisance and vibrations affecting pedestrians [25; 82]. It should also be noted that the content review revealed interesting, detailed research problems.