That insight may not seem surprising, given war’s dampening effects on economic activity. But the research employed a new tool for recognizing the effects.

Jos Lelieveld, the lead author of the study and a researcher at the Max Planck Institute for Chemistry in Mainz, Germany, said that by using tools aboard the NASA satellite Aura, he and his colleagues found decreasing levels of pollutants that corresponded to geopolitical crises that included armed conflict, trade sanctions and the rise of the Islamic State. “Each of these countries has an individual story,” he said.

International sanctions against Iran, he noted, caused an economic downturn that correlated with a steep drop in the pollutants after 2010. Nitrogen dioxide levels rose in Iraq after the war but have decreased sharply around the cities of Baghdad, Samarra and Tikrit with the rise of the Islamic State and its effect on the regional economy.

Uprisings in Syria could be tied to lower nitrogen dioxide levels over cities like Damascus and Aleppo; the Lebanese cities Beirut and Tripoli experienced increases in nitrogen dioxide levels that correlated with an influx of Syrians fleeing unrest. Public turmoil in Egypt can be associated with its decline in air pollution since 2011, he said.

Increasingly, scientists and national security experts have examined the effects of the environment on geopolitical conflict. A study released this year argued that an extreme drought in Syria between 2006 and 2009 was most likely made worse by climate change. It went on to note that the drought was a factor in the violent uprising and the rise of the Islamic State, which began ravaging that country in 2011. (Last month, the Republican Party chairman Reince Priebus ridiculed the presidential candidate Martin O’Malley for discussing that possible connection.)