Air pollution situation in small towns, including winter resorts: a comparative study of three cases in Northern Europe

In Europe, emissions of many air pollutants have decreased in recent decades, but there exist sites where concentrations of pollutants are still high and have become a public health problem. The air quality monitoring networks include urban stations in big cities and rural background stations. Main pollutants (SO₂, NO_x, CO, particulate matter) are measured automatically and reported on hourly basis, but there is very few research about air quality in small towns. The small towns are important transport nodes between cities and nowadays they are growing bigger, often being focused on seasonal tourism. In this paper, we try to understand the level of pollution in three small towns in Northern Europe, namely Otepää (Estonia), Lillehammer (Norway) and Saldus (Latvia) This research we point at seasonality of air pollution in towns related with winter sport activities, where the traffic flow increases in cold time simultaneously with heating season and higher prevalence of thermal inversions in atmospheric surface layer. Concentration peak of PM₁₀ in Northern Europe appears in early spring, in snow thawing season and shortly after that. Even higher episodic concentrations may occur near unpaved streets in dry season. High seasonal variation of measured nitrogen dioxide concentrations was found in Lillehammer and Otepää, with remarkable contributions of traffic hotspots. This paper confirms that it is worth to study the air quality in small towns, furthermore, because air pollution levels and related public health concerns in small towns are not negligible.