High levels of air pollution in parts of western Europe

High air pollution in parts of Western Europe

1 April 02:56 UTC–2 April 2014 02:58

Region

England, Germany, Belgium, Netherlands

Satellites

Metop-A and B, Meteosat-10

Instruments

GOME-2, IASI, SEVIRI

Channels/Products

Aerosol optical depth, NO2 total column density, Dust RGB, Severe Convection

On 1 April, the Global Ozone Monitoring Experiment (GOME-2) instruments on Metop-A and -B observed elevated levels of NO2 total column concentration over parts of Germany, Belgium, the Netherlands and England.

Last Updated

07 September 2022

Published on

01 April 2014

By Ruediger Lang (EUMETSAT)

In late March a large amount of Saharan dust was transported to Europe, this was still being carried to South-East England on 1 April.

Also, as shown in this RGB dust video, 1 April 08:00 UTC–2 April 08:00 UTC (Credit: Met Office/YouTube), further dust was lifted into the atmosphere on 1 April. The dust can clearly be seen being carried north towards Europe.

At the same time elevated aerosol thickness was observed over the North Sea and over the Channel area. Note: GOME-2 can currently only observe aerosol concentration over water surfaces.

RGB Dust animation, 28 March 12:00 UTC–31 March 12:00 UTC

Figure 1: Tropospheric NO2 columns, 1 April

Figure 3: Aerosol optical depth (AOD), 30 March

Figure 4: Aerosol optical depth (AOD), 22 March–6 April. The animated gif is derived from data from Metop, GOME-2, AVHRR and IASI.

On the daytime convection RGB (Credit: EUMeTrain) the dust-polluted clouds can be seen as the large yellow area.

Dust aerosols have a large impact on cloud microphysics such as cloud phase and cloud particle size.

In general, clouds that have ingested dust glaciate more quickly, forming a large number of very small ice particles. These have a higher reflectance than large ice particles in the 'microphysical' channels (near-IR 1.6 and IR 3.9 micrometer), so they appear as bright yellow in the convection RGB.

The formation of aerosols, or Particulate Matter (PM), may originate from natural or anthropogenic sources. In industrial areas aerosols may be formed through the emission of gases like NO_x, SO_x or formaldehyde (HCHO), from combustion processes which form larger particles through chemical reactions in a process called secondary aerosol formation.

Belgium, the Netherlands, the German region of Ruhrgebiet and southern Britain are known to have elevated NO₂ concentrations throughout the year, due to industrial emissions and emissions from traffic.

The formation of particulate matter or aerosols from these precursor gases depends largely on the weather conditions, including wind speed, humidity and temperature. A lack of rain over Western Europe significantly contributed to the situation.

But also the inflow of natural aerosols, like long-range transport from Saharan dust, may contribute to the overall levels of abundant levels of PM, leading to a mixed-case scenario.