Downhill city skyline of Karaj near Tehran, Iran. Photo by Germán Vogel/via Getty Images
If there is any sort of silver lining to the ongoing conflict in the Middle East, it may come in the form of fewer smog clouds.
Political upheaval, economic recession and armed conflict over the past five years drove down air pollution levels, especially smog, across the Middle East, according to the open-access report published today in “Science Advances”.
“If you look at the Middle East, you get such an entirely different picture from anywhere else on the globe,” Jos Lelieveld, the report’s lead author, said in a press conference. Lelieveld, an atmospheric physicist, directs the Max Planck Institute for Chemistry in Mainz, Germany.
Large amounts of pollutants flood the air each year due to human activities like agriculture and fossil fuel consumption. The problem is especially pronounced in developing nations, where industrialization is growing. The World Health Organization estimated that 7 million people worldwide died in 2012 due to poor air quality, with nearly half those deaths linked to outdoor air pollution. Poor outdoor air led to about one of every 16 deaths that year.
And while environmental policies have slowed carbon dioxide (CO2) emissions in some parts of the world, there is a less complete picture surrounding other pollutants like sulfur oxides (SOx) emitted from cargo ships or fossil fuel-related nitrogen oxides (NOx), which contribute to ozone, a.k.a. smog.
To monitor long-term trends in both of these air contaminants, Lelieveld and his colleagues turned to the Ozone Monitoring Instrument on NASA’s Aura satellite. Launched in 2004, Aura satellite flies in low-orbit around the planet 14 times a day, taking measurement of air quality.
When the researchers looked at satellite data collected from 2005 to 2014, they noticed a decline in both NOx and SOx pollution over the Middle East — namely, in Syria, Egypt, Saudi Arabia, Iran, central Iraq and other Arabian Gulf countries.
Moreover, the decrease in pollutants began in 2010. Prior to this year, pollution in the Middle East rivaled that of Los Angeles in the 1970s and 1980s, when smog levels boomed in the California metropolis. When the team compared the satellite measurements with economic and energy use data from the World Bank and U.S. Energy Information Administration, they concluded that the sudden drop in emissions was mostly triggered by socioeconomic instability.
The researchers argue that events like the Arab Spring, the Syrian War and trade embargoes against Iran triggered a reduction in SOx and NOx by four to six percent across the Middle East, all around the same time. These reductions occurred despite more energy use and CO2 emission in some places, like Egypt.
Sulfur dioxide trend reversal over the Arabian Gulf. (A) shows sulfur column densities averaged over 2005–2014. (B) shows changes between 2005 and 2010, while (C) portrays changes between 2010 and 2014. Courtesy of Lelieveld et al. Sci. Adv. 2015;1:e1500498
“For example, in a city like Baghdad, we see the air pollution going up until 2010, and then the activities of the Islamic State are developing,” Lelieveld said.
Pollution emissions began rising in Iraq after 2005, which paralleled their economic recovery from the war. An increase in pollution was also present in northern, Kurdish areas, which he said correlated with their economic growth.
However, since 2013, nitrogen dioxide levels in Baghdad and central Iraq have declined significantly.
The downward trend is especially apparent north and northwest of Baghdad in cities like Tikrit and Samarra where the Islamic State is active.
On the opposite end, the recent movement of refugees has spawned air pollution. “Now while [in] Syria and Iraq, the flows of refugees have reduced air pollution, in Jordan and especially in Lebanon, the air pollution has strongly increased,” Lelieveld said.
Also in 2010, Iran experienced a strong decline in air pollution, including that created by tanker ships in the Persian Gulf. This time frame corresponded with the U.N. Security Council tightening sanctions and the U.S. imposing a comprehensive Iran sanctions, accountability and divestment act.
The effects of the boycott were considerable, cutting emissions from international shipping in the Gulf region by a factor of two, Lelieveld said.
The team noted reductions in air pollution following 2010 in areas without strife too, such as in Saudi Arabia, Kuwait and the United Arab Emirates, which implemented air quality control policies. They also spotted fewer NOx emissions in Greece after 2008, following the financial crisis.
Lelieveld pointed out that air measurements from space won’t stop armed conflicts in this region, but could help environmental policy. Given that trends in SOx and NOx didn’t always mirror carbon emissions in the Middle East and the fact that air quality stations aren’t available across the region, Lelieveld argues that satellite readings might provide a more accurate picture of pollution.
“It is simply a new diagnostic that can help analyze what’s going on in certain areas,” he said. “The amount of information that will become available from these satellites … will be fantastic.”
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