Ammonium nitrate explosion at the main port in Beirut (Lebanon) and air pollution: an analysis of the spatiotemporal distribution of nitrogen dioxide

An explosion of the ammonium nitrate (AN) stored at Beirut Port devastated the city on Tuesday 4 August 2020. Such an explosion produces pollutants such as nitrogen oxides (NO(x)). The most common NO(x) is nitrogen dioxide (NO(2)), which is present in the atmosphere due to natural and anthropogenic processes. The presence of NO(2) is used as indicator of air pollution. However, the specific contribution of NO(2) to air quality is uncertain due to the presence of other constituents, especially particulate matter (PM10). Research has shown that extended exposure to NO(2) may result in serious health effects. This study investigated the impact of the explosion on NO(2) levels in the atmosphere above Beirut and the surrounding area. NO(2) data from the Sentinel-5P program were used to map the levels of NO(2). Furthermore, ground-monitoring data were used to assess the levels of PM10 and ozone (O(3)) due to the evident association between these constituents and NO(2). Results showed that NO(2) levels were higher than before the blast. However, 7 days after the explosion, NO(2) levels had returned to normal, while the levels of PM10 and O(3) remained normal following the explosion. However, a slight increase in the daily average atmospheric pressure was noticed after the explosion, which was attributed to the decomposition of ammonium nitrate.