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.