Aerosols and micrometeorology

Work focuses on the development and application of micrometeorological flux measurement techniques and instrumentation to quantify surface/atmosphere exchange fluxes of a range of gases and aerosols. Gases include carbon dioxide, the other major greenhouse gases (i.e. methane and nitrous oxide) and reactive nitrogen compounds with emphasis on ammonia and nitric acid. Fluxes of aerosols include total number fluxes, size-segregated number fluxes (0.1 to 10 m) and fluxes of individual aerosol components and trace metals.

One emphasis of the work is the application of micrometeorological flux measurement techniques to the urban environment, not just for CO2, but a range of gases and aerosol compounds. A further emphasis is the application of flux measurements to investigate chemical interactions of gases and aerosols (e.g. gas-to-particle conversion) following emissions from biogenic, agricultural and combustion derived emissions both above vegetation and urban areas.

Recent instrument developments included a continuous relaxed eddy accumulation system for atmospheric ammonia and an eddy-covariance system for aerosol components, based on aerosol mass spectrometry.

CEH scientists have also been involved in the study of turbulence characteristics in and above vegetation canopies as well as in the urban environment, and in the development of new (e.g. time-integrated) flux measurement approaches.

Instrumentation and facilities

Aerodyne Aerosol Mass Spectrometer for the measurement of concentrations, size-spectra and eddy-covariance fluxes of individual aerosol components (e.g. ammonium, nitrate, sulphate, organics).

GRAEGOR: Gradient System for Reactive Aerosols and Gases with Online Registration for the measurement of fluxes of gas-phase NH3, HNO3, HCl, HONO and SO2 as well as aerosol NH4+, NO3-, SO4=, Cl- with the aerodynamic gradient approach.

PTRMS: Ionicon Proton Transfer Reaction Mass Spectrometer for the measurement of VOC concentrations and fluxes.

TDL-AS: Tunable Diode Laser Absorption Spectrometers for the rapid measurement of CH4, N2O, NH3 and HNO3.

Projects

Urban flux measurements of gases and aerosols

Surface/atmosphere exchange fluxes of reactive gases and aerosols and gas-particle interactions

Quantification of greenhouse gas exchange (CO2, N2O, CH4).

Boundary layer budget studies

Studies of turbulence characteristics

Measurement, mapping and modelling of heavy metal deposition in the UK