## 1 Introduction
A study by [PERSON] and [PERSON] [9] estimated that the average cost of air pollution in Europe is EUR 1250 per person annually, representing 3.9% of the average urban income. The same analysis projects that air pollution costs in Romania could reach EUR 3000 per person, accounting for 8-10% of average urban income. In 2018, Bucharest ranked second among 432 cities analyzed for air pollution-related economic losses, with an estimated annual cost of EUR 6.35 billion, just below London's losses. The study by [PERSON] and [PERSON] [9] covered cities with a combined population exceeding 130 million and total losses of EUR 166 billion. In Romania, Bucharest bears the highest welfare-related financial losses due to air pollution, estimated at EUR 6.35 billion annually, followed by Timisoara at EUR 542 million and Brasov at EUR 496 million. Given the significant increase in health costs and the future economic implications of air pollution, it is crucial to explore its profound health impacts. Clinical observations and research studies provide compelling evidence of the detrimental effects of air pollution on human health. In high-population healthcare facilities, an increase in cardiovascular and respiratory conditions has been observed in recent years, with seasonal fluctuations likely linked to air pollution levels [10; 11; 12]. Specifically, studies have established a strong correlation between the incidence of asthma and chronic obstructive pulmonary disease (COPD) and prolonged exposure to pollutants [13]. In Romania, research has confirmed a direct relationship between hospital admissions and rising levels of air pollution, underscoring the urgency of addressing this public health crisis. For instance, in a recent study, [PERSON] [14] used PM\({}_{2.5}\) and PM\({}_{10}\) data from the Airly [15] platform in Bucharest and correlated these with hospitalization data for chronic diseases (respiratory, cardiovascular, cerebrovascular, and metabolic) obtained from the Romanian National Institute of Public Health (RNIPH) [16]. The study, covering the period from 20 August 2018 to 1 June 2022, revealed a significant statistical association: for every 10 \(\mu\)g m\({}^{-3}\) increase in PM\({}_{2.5}\) and PM\({}_{10}\) levels, hospital admissions for respiratory and cardiovascular conditions surged by 40-60%, cumulatively resulting in nearly 2000 additional admissions per disease over the study period. This research highlights the direct, proportional impact of air pollution on health, demonstrating that elevated levels of particulate matter significantly increase hospital admissions for a range of chronic diseases, including respiratory and cardiovascular conditions, strokes, and diabetes. Notably, an 85% reduction in such hospitalizations was observed in Bucharest between April and May 2020, likely due to the COVID-19 pandemic restrictions [14]. The lockdown periods in Europe during the COVID-19 pandemic presented a unique opportunity to study air pollution in highly populated urban areas [17]. The significant reduction in human activity and transportation during these lockdowns led to a notable decrease in emissions, enabling researchers to investigate the impact of reduced anthropogenic activities on air quality in unprecedented ways [18; 19]. This exceptional situation offered valuable data for analyzing the relationship between human actions and air pollution levels, providing critical insights for future environmental policies and urban planning strategies [20]. Studies conducted during the lockdown periods revealed substantial improvements in air quality, with marked decreased levels of nitrogen dioxide (NO\({}_{2}\)), particulate matter (PM\({}_{2.5}\) and PM\({}_{10}\)), and other pollutants [21; 22; 23]. However, these studies also indicated that while NO\({}_{2}\) concentrations significantly decreased due to the lockdown measures, there was a concurrent increase in ozone (O\({}_{3}\)) pollution in urban areas.