Yesterday was a beautiful sunny day on the ground and as we needed to go to the hangar for a maintenance job we decided to go for a quick evening flight. At only ' we could start to see the murkiness of the volcanic dust cloud above us. OK so it's not unusual to have haze cutting down the visibility, nor is it unusual to have a dark smudge in the sky at the *inversion level especially this close to London, but this did seem excessively grotty for want of a better term, particularly as you don't normally see the inversion layer when looking towards the sun. I know some countries, and even some parts of our country have it far worse than this as we are just on the edge here.
*The inversion is a level in the atmosphere where two masses of air sit on top of each other. The layer below will be warmer air trapped my a layer of colder air on top. You often get a layer of cloud here but on blue cloudless days you can often see a dirty smudge just below this layer when looking away from the sun. This is all the dirt, dust and pollutants that get mixed up in the air and have risen in the warm air to the top of this level just like smoke floating to the ceiling of a room. You don't normally see it looking towards the sun even though it's there due to an optical illusion just like you can't see a rainbow in that direction, but on this flight we could see it in all directions.