The lidar instrument aboard the CALIPSO satellite sends out pulses of light that bounce off particles in the atmosphere and back to the satellite. It distinguishes dust from other particles based on optical properties.
A recent using NASA’s satellite described how wind and weather carry millions of tons of dust from the Sahara desert to the Amazon basin each year – bringing much-needed fertilizers like phosphorus to the Amazon’s depleted soils.
To bring this story to life, NASA Goddard’s Scientific Visualization team produced a showing the path of the Saharan dust, which has been viewed half a million times. This story is notable because it relies on satellite technology and data to show how one ecosystem’s health is deeply interconnected with another ecosystem on the other side of the world.
Being able to see the dust blowing in the wind has broad implications. Today, one in eight people in the world dies from exposure to air pollution, which includes dust. This stunning fact, issued by the World Health Organization last March, adds up to 7 million premature deaths per year. Air pollution is now the in the world, and it occurs both indoors and outdoors.
The WHO report, which more than doubles previous estimates, is based on improved exposure measurements including data collected from satellites, sensors and weather and air flow information. The information has been cross-tabulated with demographic information to reveal, for example, that if you are a low- to middle-income person living in China, your chances of dying .
In addition to the volume of satellite data generated by NASA, sensor technology that helps create personal pollution monitors is increasingly affordable and accessible. Projects like the , and the (with which I collaborate) are working to put tools to collect data from the ground in as many hands as possible. These low-cost devices are creating opportunities for citizen science to fill coverage gaps and testing this potential is a key part of our upcoming installation of DustDuino units in Sao Paulo, Brazil later this summer. Satellite data tend to paint in broad global strokes, but it’s often local details that inform and motivate decisions.
Satellites give us a global perspective. The official monitoring infrastructure, overseen by large institutions and governments, can measure ambient air at a very high resolution and modeling exposure over a large area. But they don’t see everything. The nascent field of helps citizen scientists and journalists fill in the gaps in monitoring networks, identifying human exposures and hot spots that are invisible to official infrastructure.
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