VOTALP II: Vertical ozone transports in the alps

• Unité de recherche: PCRD EU
• Numéro de projet: 97.0021-2
• Titre du projet anglais: VOTALP II: Vertical ozone transports in the alps

Mots-clé (Anglais)

Ozone; summer smog; air pollution alpine valley; photooxidants

Autre Numéro de projet (Anglais)

EU project number: ENV4-CT97-0413

Programme de recherche (Anglais)

EU-programme: 4. Frame Research Programme - 3.1 Environment

Description succincte (Anglais)

See abstract

Partenaires et organisations internationales (Anglais)

Coordinator: Universität für Bodenkultur (A)

Résumé des résultats (Abstract) (Anglais)

The main objectives of the PSI contribution to VOTALP are
· the study of vertical pollutant exchange over Alpine foothills by budget analysis of aircraft measurements, including ozone soundings,
· investigation of advection of the urban plumes of Milano and Munich into the Alpine area by aircraft measurements,
· statistical investigation of the effect of urban plumes on the Alpine foothills, using aircraft measurements of former campaigns,
· evaluation of the effect of emission reductions in the Milano area and the Po valley on the pollutant concentrations in the Mesolcina valley, using a Lagrangian photochemical model.
The following results are found
· Considerable concentration increases above Alpine foothills can be observed. Alpine foothills cannot be neglected regarding vertical pollutant transport. These budget studies were the first studies ever to characterise vertical net transport of pollutants over foothills.
· Compared to deep Alpine valleys, pollutants are not injected to very high altitudes like 3000 to 4000 mASL above the Mesolcina valley as found in VOTALP I.
· Vertical net wind speed can be up to 0.1 m/s.
· Milano is a strong pollutant source. The pollutants of this area often hit the Alpine foothills in summer months.
· In northerly Foehn situations, free tropospheric air is brought down to the boundary layer of the Alpine foothills. The concentrations are low in summer, high in winter during these cases.
· Ozone levels have decreased in the 90ies in the Alpine foothills.
· Benzene concentration levels are relatively low in comparison to the total VOC load in the Po Basin due to regulations in Italy that the benzene content in the gasoline is lower than 1 %.
· Results from the PSI contribution suggest a new distinction of 3 vertical air layers in the Alpine area: planetary boundary layer, injection layer (new), and free troposphere.

Références bases de données (Anglais)

Swiss Database: Euro-DB of the
State Secretariat for Education and Research
Hallwylstrasse 4
CH-3003 Berne, Switzerland
Tel. [phone]
Swiss Project-Number: 97.0021-2