Satellite observations for monitoring atmospheric NO 2 in correlation with the existing pollution sources under arid environment.

Monitoring of air pollutants using satellite data has been largely improved over the past few decades, which can provide deeper insights into the effects of anthropogenic activities on the air quality. The observations and measurements of atmospheric NO 2 are poorly investigated in North Africa, therefore, the current study applied a multi-proxy approach to better understand of the ambient environment. This approach is based on satellite observations, chemical and biological analyses, and investigative information during fieldworks. The Aura satellite provides the basic data for the current study with fine resolution of atmospheric NO 2 and O 3 concentrations. The obtained results reveal noticeable increases of atmospheric NO 2 values since the 2011, where its emission reaches the peak during summer season that is characterized by high anthropogenic activities. The study area has many sources for NO 2 emissions, such as the urban region, traffic, as well as the NH 3 emission that is in turn converted to NO 2. Although the discharged and spreading wastewater (80,000 m 3 /day in summer) has a limited role in NO 2 emissions, it represents an indicator of the anthropogenic activities. The wastewater analyses confirm the occurrence of nitrate (NO 3 - ), nitrite (NO 2 - ), and ammonia (NH 4 + ), which provide an appropriate condition for NO 2 release. The analyses of multi-climate datasets (previous records and the expected scenarios) reveal an increase of temperature accompanied by decrease of precipitation which confirmed the existence of climate change. Therefore, the study presents a set of suggestions to mitigate the release of NOx gases and achieve Net-Zero emissions.