BBC: The 2010 eruption of the volcano Eyjafjallajökull in Iceland resulted in an ash cloud that shut down airspace across Europe. At the time, any ash in the air was enough to cancel flights. Those flight cancellations resulted in complaints that the danger was overestimated and cost airlines more than £1 billion. Now the UK uses a three-tier system for judging volcanic ash threats. To accurately assess the thickness of atmospheric ash, the UK's Met Office is setting up 10 stations that use lasers to measure ash cloud heights and thickness. The stations will be able to measure the reflection rate of the clouds, differentiate between volcanic ash and other particulates, and also track the clouds in real time.
