The purpose of this research paper is to investigate and identify the factors which can support the development of one characteristic of smart cities, namely, the smart environment. More specifically, the main goal is to measure the extent to which air pollution may be reduced, taking as determinants several circular economy, fiscal, and environmental factors. The Ordinary Least Squares, the Fixed Effects, and Random Effects regression models using balanced panel data were employed, over the 2011–2019 period, for 28 European states. After rigorously studying the literature, 11 indicators with a predictable impact on the exposure to air pollution were kept. According to current analysis, the most effective methods of reducing air pollution are the use of renewable energy, the investments in educating the population to reduce pollution, the proper implementation of the circular economy, and the adoption of the most suitable policies by the European Union governments. Particular attention needs to be paid to factors such as carbon dioxide-generating activities, which are significantly increasing the air pollution. Another strong value is that of providing information on the assessment of ambient air quality, and on the promotion of appropriate policies to achieve two major objectives: well-being, and sustainable cities.

The Schengen project is one of Europe’s most important accomplishments as it facilitates the free movement of goods and people. Currently, Romania and Bulgaria are on the verge of obtaining their Schengen membership and, to our knowledge, not enough emphasis has been placed on the emigration and labour market implications for aspiring candidates. This research aims to empirically evaluate the liaison between Schengen Area and labour migration. To achieve this objective, we construct a difference-in-differences research design using data from the European Labour Force Survey. The treatment is represented by the Schengen enlargement of 2007 with Latvia, Lithuania and Estonia constructing the treatment group and Romania and Bulgaria the control group. The main results show that Schengen Membership led to an increased probability of working abroad one year after treatment occurred, as well as three years after treatment occurred. Also, we can identify the demographic category most likely to emigrate as young males in search of seasonal full-time jobs