Spatial Assessment of Nitrogen Dioxide (NO2) in Lithuania’s Coastal Zones: A Remote Sensing Approach for Sustainable Urban Planning

Nitrogen dioxide (NO2) is a short-lived atmospheric pollutant primarily emitted by road traffic, maritime shipping, and industrial combustion. It is a key indicator of anthropogenic air pollution due to its harmful health effects, its role in the formation of secondary particulate matter, and its strong association with other traffic-related pollutants. Elevated NO2 concentrations are closely linked to respiratory and cardiovascular diseases, with children and elderly populations being particularly vulnerable due to physiological susceptibility and exposure patterns. This study uses satellite-based remote sensing data to assess the spatial and temporal variability of NO2 concentrations in the Lithuanian coastal zone and adjacent marine areas. The analysis focuses on identifying spatial patterns of NO2 concentration distribution, localized pollution hotspots, and their relationships with population distribution. Correlation analysis for the 2022–2024 period revealed a statistically significant negative relationship between NO2 concentrations and distance from the coastline in inland areas, whereas no statistically significant relationship was observed offshore. NO2 concentrations at 0 m and 50 m were strongly positively correlated across all spatial domains and seasons (r > 0.98, p < 0.001), indicating consistent vertical spatial patterns. Annual mean NO2 concentrations were also strongly positively associated with population density (r = 0.81).