17. July 2017
Air pollution in Europe's urban areas

HA­LO re­search air­craft mea­sures emis­sions from ma­jor cities

HALO research aircraft
HA­LO re­search air­craft
Image 1/5, Credit: DLR (CC-BY 3.0).

HALO research aircraft

The HA­LO re­search air­craft flies all over the world for at­mo­spher­ic and cli­mate re­search.
BAe 146 re­search air­craft
Image 2/5, Credit: DLR (CC-BY 3.0).

BAe 146 research aircraft

The BAe 146 re­search air­craft be­long­ing to the British FAAM (Fa­cil­i­ty for Air­borne At­mo­spher­ic Mea­sure­ments) is be­ing used in par­al­lel with HA­LO around Lon­don.
HA­LO above the Al­lianz Are­na in Mu­nich
Image 3/5, Credit: DLR (CC-BY 3.0).

HALO above the Allianz Arena in Munich

En route to the planned des­ti­na­tions, low-lev­el flight mea­sure­ments are al­so tak­ing place above near­by Mu­nich.
HALO in flight
HA­LO in flight
Image 4/5, Credit: Aero-Art Frank Herzog.

HALO in flight

31 re­search in­sti­tutes are in­volved in the HA­LO project.
HALO: High Altitude and Long Range Research Aircraft
HA­LO: High Al­ti­tude and Long Range Re­search Air­craft
Image 5/5, Credit: DLR (CC BY-NC-ND 3.0)

HALO: High Altitude and Long Range Research Aircraft

The HA­LO re­search air­craft is unique in the world and is open­ing up new di­men­sions in the study of the at­mo­sphere. The com­bi­na­tion of range, cruis­ing al­ti­tude, pay­load and com­pre­hen­sive in­stru­men­ta­tion make the air­craft a glob­al­ly unique re­search plat­form.
  • Measurements of emissions above London, Rome and the Ruhr region
  • Focus on movement and photochemical conversion of emissions
  • Including low-altitude flight measurements
  • Focus: Aviation, Environment, Air pollution control

Emissions from major cities can spread beyond the limits of these urban areas under certain weather conditions. When this happens, the wind often carries particles and gaseous pollutants over 1000 kilometres. The German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) is currently carrying out a series of research flights, lasting until until 30 July, to find out more about the distribution and conversion of emissions from London, Rome, the Ruhr region and other European urban areas. Scientific leadership of the international EMeRGe project (Effect of Megacities on the transport and transformation of pollutants on the Regional and Global scales) is the responsibility of the University of Bremen. The aim is to better understand and be able to predict the extent and effects of air pollution from populated areas on Earth's atmosphere.

"In total, 52 flight hours are planned over some of Europe's metropolitan regions by the end of July," says project leader John P. Burrows from the Institute of Environmental Physics at the University of Bremen. "In total, 52 flight hours are planned over some of Europe's metropolitan regions by the end of July," says project leader John P. Burrows from the Institute of Environmental Physics at the University of Bremen. The HALO research aircraft is equipped with a total of 20 instruments to capture the various gas and particle emissions from major cities. "We want to understand in detail how emissions are spatially distributed in the atmosphere under different weather conditions and find out which conversion processes take place that lead to secondary photooxidants and aerosol particles," says Hans Schlager from the DLR In­sti­tute of At­mo­spher­ic Physics. "For example, we are investigating the formation of ozone from nitrogen oxides, hydrocarbons, particles of sulphur dioxide and organic precursor compounds."

Altitude profile of pollutant distribution

The modern High Altitude and Long Range Research Aircraft (HALO) takes off each time from its home base in Oberpfaffenhofen, near Munich, for measurement flights over various European metropolitan areas. "To give the researchers an accurate picture of the distribution of urban emissions, HALO flies at progressively higher altitudes, initially at around 1000 metres, then climbing to three and then five kilometres," says Frank Probst from the DLR Flight Op­er­a­tions (FB). "In cities such as London or a heavily-populated area such as the Ruhr region, this needs detailed planning and the approval of the relevant local air traffic control authority, as we are carrying out measurement flights in very crowded airspace." Furthermore, as the flights are at relatively low altitudes, they need to be carried out under cloud-free conditions so that the aircraft can fly into the exhaust gas plumes of the cities.

Visual flight at low altitude

The flight segments – which sometimes take place less than a kilometre above the ground, for example over the Po Plain in Italy – are particularly challenging. "In low-level flight, in addition to close coordination with air traffic control, we are reliant upon visual flight," says DLR research pilot Marc Puskeiler. "At this altitude there are a lot of light aircraft and helicopters that we have to look out for to ensure safe operations."

Joint measurement flights over London

On July 17, the researchers carried out a HALO measurement flight into the large-scale pollutant plume over London. This was done jointly with the BAe 146 research aircraft belonging to the British FAAM (Fa­cil­i­ty for Air­borne At­mo­spher­ic Mea­sure­ments) . London is the only European megacity with over 10 million inhabitants. Investigations there are of particular interest for comparisons with HALO measurements in the vicinity of Asian megacities such as Taipei, which are planned for March 2018.

In parallel with the HALO flights, additional measurements using other aircraft are also taking place in Britain and Italy. Furthermore, ground-based measurements and laser-based lidar observations are being used across Europe for planning and assessing the HALO flights. Six HALO measurement flights above Europe are planned up to the end of July. DLR has been providing information via its social media channels on where the flights are taking place.

Project with around six million euros in funds

Other project partners are the Max Planck Institute for Chemistry, the Universities of Mainz, Heidelberg and Wuppertal, as well as the Karlsruhe Institute of Technology and the Jülich Research Center. The project is financed until April 2018 by the German Research Foundation (Deutsche Forschungsgemeinschaft; DFG), the Max Planck Society (Max-Planck-Gesellschaft; MPG) and DLR, with some six million euros.

About HALO

The HALO research aircraft is a joint initiative of German environmental and climate research institutions. HALO was procured with funds from the German Federal Ministry of Education and Research (BMBF), the Helmholtz Association and the Max Planck Society. HALO is operated by the German Research Foundation, the Max Planck Society (MPG), Jülich Research Center (FZJ), Karlsruhe Institute of Technology (KIT), the German Research Centre for Geosciences (Deutsches GeoForschungsZentrum; GFZ) in Potsdam and the Leibniz Institute of Tropospheric Research in Leipzig (TROPOS). DLR both owns and operates the aircraft.

  • Falk Dambowsky
    Ger­man Aerospace Cen­ter (DLR)

    Com­mu­ni­ca­tions and Me­dia Re­la­tions
    Telephone: +49 2203 601-3959
    Linder Höhe
    51147 Cologne
  • Dr Hans Schlager
    Ger­man Aerospace Cen­ter (DLR)
    In­sti­tute of At­mo­spher­ic Physics
    In­sti­tute of At­mo­spher­ic Physics
    Telephone: +49 8153 28-2510
    Fax: +49 8153 28-1841
    Münchener Straße 20
    82234 Oberpfaffenhofen
  • Frank Probst
    Ger­man Aerospace Cen­ter (DLR)

    DLR Flight Ex­per­i­ments Fa­cil­i­ty
    Telephone: +49 8153 28-1197
    Linder Höhe
    51147 Köln
  • Marc Puskeiler
    Ger­man Aerospace Cen­ter (DLR)
    Flight Ex­per­i­ments
    Lilienthalplatz 7
    38108 Braunschweig
  • Prof. John P. Burrows
    Uni­ver­si­ty of Bre­men

    In­sti­tute of En­vi­ron­men­tal Physics
    Telephone: +49 421 218-62100

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