RESEARCH TEAM:
• Remote Sensing of NO₂ in European Coastal Regions
Project leader: Prof. Bogdan Zagajewski
Team:
Oliwier Zając, BSc;
Patryk Grzybowski, MSc;
Marlena Kycko, PhD
Nitrogen dioxide (NO₂) is harmful to human health and the environment—its presence in the atmosphere is directly linked to intense road traffic, heating of buildings, and industrial activities. Today, thanks to Sentinel-5P satellite data, regular observation of NO₂ concentrations over extensive areas is possible. A team from the Department of Geoinformatics, Cartography, and Remote Sensing at our faculty analysed the variability of NO₂ in the coastal zones of six European countries.
Nitrogen dioxide is one of the main components of smog, affecting not only the air quality but also the health of the residents in large cities. In 2013, the WHO classified NO₂ as a carcinogenic substance. Its primary sources of emission are road transport and fuel combustion in buildings. Between 2019 and 2022, we analysed the changes in the NO₂ concentration using data from the European satellite Sentinel-5P, which measures the gas content within the tropospheric column (the lowest layer of the atmosphere). Satellite data were compared with ground-level measurements from monitoring stations to verify their accuracy. The analysis covered the coastal zones and capitals of Poland, Romania, Italy, Spain, Portugal, and the Netherlands. The highest concentrations of nitrogen dioxide were detected along the coast of the Netherlands, especially near ports and industrial areas. In Poland and Romania, increases in pollution were identified on the outskirts of Warsaw, Gdańsk, and Bucharest. Researchers also accounted for seasonal differences. Concentrations were highest in the winter—in 2021 they were as much as 74% higher than in summer. The smallest seasonal differences were recorded during the pandemic year of 2020, possibly due to mobility restrictions. Land cover type data were also used to identify areas with the highest pollution levels. Surprisingly, high NO₂ concentrations were found not only in industrial zones and airports but also in urban green spaces, possibly indicating proximity to intensive road traffic. Spatial and temporal analyses identified areas particularly exposed to pollution and confirmed a seasonal emission pattern. This project demonstrates how modern remote sensing tools can support air quality monitoring across Europe.
Upper graphics:
↑ Scatter plot showing the relationship between Sentinel-5P column measurements of NO₂ and ground-level measurements. Analysis based on monthly averages from 2019 to 2022 in studied European coastal zones (Author: O. Zając).
Lower graphics:
↑ FROM THE LEFT.
Map showing the location of Poland’s coastal zone (a); Boxplot showing values for all pixels from annual median NO₂ imagery for 2019–2022 (b); Maps presenting time series for the coastal zone and a buffer created for Warsaw (c); Maps of statistically significant changes in NO₂ content over four full years (2019–2022), generated using linear regression (d) (Prepared by: O. Zając).
Maps showing time series of NO₂ measurements for the coastal zone of the Netherlands (a); Map of the location of the Netherlands’ coastal zone (b); Maps showing changes in NO₂ content over four full years (2019–2022), generated using linear regression (c); Boxplot showing values for all the pixels from annual median NO₂ imagery for 2019–2022 (d) (Prepared by: O.Zając).
Time series of Sentinel-5P column NO₂ measurements for the entire research period—results for all pixels corresponding to the locations of 176 analysed ground-level stations (grouped by months) (Prepared by: O. Zając).
RESEARCH LOCATION: Europe (POLAND / ROMANIA / ITALY / PORTUGAL / NETHERLANDS)