Nitrogen Dioxide

Nitrogen dioxide is a gas emitted during the combustion of fossil fuels. It's released from the tailpipes of cars, and the smokestacks of power plants. Together, these emissions affect the quality of the air we breathe. Since 2004, an instrument aboard NASA's AURA satellite has measured levels of nitrogen dioxide in Earth's atmosphere. In 2014, we released satellite images that show how environmental regulations have led to reductions in nitrogen dioxide over major U.S. cities. Now, we've created global maps that allow us see how levels have changed around the world over the last decade. In Western Europe, despite the recent vehicle emissions scandal, nitrogen dioxide levels have decreased by as much as 50 percent due to tighter environmental controls. In China, we see an increase in levels over most of the country, due to a rise in coal use for power generation but decreases for some cities, like Beijing, where a growing middle class is now demanding cleaner air. In the Middle East, we see decreases in nitrogen dioxide levels over Syria due to the country's civil war and displacement of its population. Meanwhile, levels have gone up in neighboring countries where millions of Syrians have taken refuge. In the U.S., the only increases are in regions with intensive oil and natural gas extraction, including fracking. In North Dakota and Texas, we see increases of 30% in some areas. By monitoring levels of nitrogen dioxide from space, we can see and quantify the effects of things like energy usage environmental policy and even civil unrest on air quality across the globe.