1 May 2014

Potten End Newsletter Article 16

This article originally appeared in the Potten End Newsletter, May 2014.

Potten End Weather

“Water and air,
the two essential fluids on which all life depends,
have become global garbage cans.”
― Jacques-Yves Cousteau

In early April much of the country experienced periods of very high levels of air pollution caused, in part, by Saharan dust.

Storms in the Sahara whipped up a large amount of sand and dust into the upper atmosphere. Saharan dust settling in the UK is nothing unusual and can happen several times a year. Winds of around 20mph are required to lift sand into the atmosphere, and the Sahara had been experiencing wind storms in excess of 40mph at the time.

Normally the sand and dust settles in the countries of Southern Europe. In April however, winds from the south and east combined the sand and dust with industrial pollution from Europe. Our weather at the time was stable and calm which meant that the pollution gathered over the UK and was not dispersed.

According to The Department for Environment, Food and Rural Affairs (Defra), certain areas reached 10 out of 10 – or “very high” – on its air cleanliness scale for a few days.

When levels reach 7 to 9 on Defra’s scale, adults and children with lung problems and adults with heart problems are advised to reduce exertion.

When pollution levels reach 10, the general population is told to “reduce physical exertion, particularly outdoors, especially if you experience symptoms such as sore eyes, cough or sore throat”.
The deposit of fine Saharan sand on cars and buildings was just one visible effect of the event. The air was visibly hazy with some reporting a distinctly blue tinge to it. This resulted in some incredible sunsets.

Fortunately the event passed after a few days when wind and rain helped to disperse the pollution and remove the sand and dust from the air.

Recent studies suggest that air pollution can have wide-ranging effects on the weather. Parts of China and Asia have the highest levels of air pollution in the world and researchers have found that, especially during winter, these pollutants strengthen storms above the Pacific Ocean, which in turn feed into weather systems in other parts of the world.

The effects can be quite dramatic with the pollution causing thicker and taller clouds leading to heavier precipitation.