# A Comparative Study of SOx, NOx, PM2.5 and PM10 in the UK and Poland from 1970 to 2020
## 1 Introduction  
We encounter various pollutants on a daily basis, many of which are invisible to the naked eye, but pose threats to human health and the environment. Even a slight alteration in their presence in the atmosphere can lead to grave repercussions. The issue of air pollution stands as a significant public health concern, exerting a profound impact on the well-being and survival of human communities worldwide [1]. Both outdoor and indoor air pollutants contribute significantly to respiratory and other illnesses, serving as a notable cause of morbidity and mortality [2; 3; 4; 5; 6]. According to data from the World Health Organization (WHO), nearly the entire global population (99%) inhales air surpassing WHO guideline limits, containing elevated levels of pollutants. This predicament is particularly pronounced in low- and middle-income countries, where the highest levels of exposure are observed [1]. Before the modern era, natural processes such as volcanic eruptions, forest fires, lightning, and the decomposition of organic substances were the only sources of pollution [7]. These processes produced carbon monoxide, nitrogen oxides (NOx), methane, ash, and volcanic gases, including carbon dioxide [7; 8].  
The proliferation of motorised transport and industrialisation has heightened the demand for energy derived from fossil fuels, such as oil, natural gas, and coal [9; 10; 11; 12; 13; 14; 15; 16; 17; 18; 19; 20; 21; 22; 23; 24]. The combustion of these in air gives rise to the formation of oxides of carbon, sulphur, and nitrogen. The quality of the air we breathe is intricately connected to the Earth's climateand global ecosystems [25; 26; 27]. Many factors driving air pollution, notably, the combustion of fossil fuels, are also significant contributors to greenhouse gas emissions [28]. Consequently, initiatives aimed at mitigating air pollution present a mutually beneficial strategy addressing both climate concerns and public health [29; 30; 31]. By reducing the burden of diseases linked to air pollution, such policies contribute to both the immediate and long-term efforts to alleviate the impacts of climate change [1]. Therefore, in recent years, environmental economists have been relentless in their efforts to gain a more comprehensive understanding of the relationship between industrial activities and pollution [32].  
This paper focuses on the air pollution dynamics in the UK from 1970 and 2020, aiming to elucidate the factors driving these changes and establish correlations with industrial characteristics. Specifically focusing on sulphur dioxide, nitrogen dioxide, PM2.5, and PM10--key air pollutants--this paper delves into various factors influencing changes in pollutant concentrations. These factors include the intensity of industrial production, the utilisation of diverse energy sources, and the interplay between temperature and traffic intensity. In addition, regional and international regulations put in place by the authorities to prevent an increase in pollution are analysed. The analysis extends to a comparative study between the UK and Poland, the latter being a country grappling with significant air pollution in Europe, particularly due to its reliance on coal for energy. In contrast, the UK has been progressively transitioning to alternative energy sources. This shift is reflected in differing pollutant concentrations linked to the energy sources employed by these countries. Unlike many previous studies that often focused on individual pollutants or those overlooked in recent years, this article undertakes a comprehensive analysis considering recent data. Additionally, it draws comparisons with another European Union country, fostering discussions on the observed differences.