Search

Long-range transported air pollution has markedly decreased in Ireland and Europe over the last two decades. Yearly average nss-sulphate concentration has dropped by 70% at Mace Head during the last decade alone. Backward air mass trajectories indicated little contact with the North American continent precluding significant transport of anthropogenic particulate matter in an increasingly cleaner atmosphere. Polluted easterly air masses from the European continent rarely reach as far as the mid North Atlantic, making the eastern North Atlantic one the cleanest regions in the Northern Hemisphere. Carbon isotope analysis [1] has confirmed the above findings also for carbonaceous particulate matter. The influence of natural biogenic components including biogenic non-sea-salt sulphate and sea salt is having increasing impact on air quality and cloudiness with significant climatic implications.

Two flights have been performed by the FAAM BAe 146-301 large Atmospheric Research Aircraft in the coastal atmosphere of Mace Head, Ireland, on the 9th and the 10th of December 2010 in the framework of the Marine Aerosol–CLOUD Interactions (MACLOUD) field campaign to study the microphysics of two liquid stratocumuli. Instruments onboard the FAAM BAe aircraft provided in situ measurements of the main liquid cloud microphysical variables. The latest-generation cloud microphysics retrieval method SYRSOC (SYnergistic Remote Sensing Of Cloud) has been compared with the microphysics observed by the in-situ aircraft measurements and with the METEOSAT Second Generation geostationary system, the Spinning Enhanced Visible and Infra Red Imager (SEVIRI). Synergistic profiling from LIDAR, Doppler ka-band cloud RADAR and humidity and temperature microwave radiometer have been used by SYRSOC to retrieve profiles of cloud droplet number concentration (CDNC), droplet effective radius (Reff) and liquid water content (LWC) ...

The high-time resolution sea salt measurements using the High Resolution Time of Flight Aerosol Mass Spectrometer (HR-ToF-AMS) enabled the identification and quantification of sea salt mass in the sea spray aerosol plumes, indicating the predominant sea salt contribution during low biological activity periods. Both mass and number flux source functions were derived and found to have a typical power-law wind speed dependency. Comparison of the mass flux relationship with the previously existing functions suggests that previous schemes based on the Monahan whitecap-wind speed approach significantly over-estimate the submicron mass flux. Both the whitecap - wind speed component and the differential whitecap-aerosol productivity component of the source flux function contributes towards the over-estimation.

In this work a regional model is deployed in order to determine the effect of trans boundary species on speciated aerosol concentrations over Ireland. A Regional Climate model is deployed and simulations are run for January and August 2006 in order to quantify the magnitude of this pollution transport and its contribution to ambient concentrations.

Aerosol light scattering measurements were carried out at the Global Atmosphere Watch (GAW) research station, Mace Head, on the west coast of Ireland. Analysis of ten years (2001-2010) of the aerosol light scattering coefficient (σscat) at 550nm reveals a strong seasonal trend with σscat values during the winter season being approximately three times that of the summer season. The σscat and the aerosol light backscattering coefficient (σbscat) for the winter (Low Biological Activity – LBA) and the summer (High Biological Activity-HBA) are dependent on the square of wind speed (U). Scattering properties for the LBA period are approximately twice those of the HBA period. 70% of the observed LBA-HBA scattering difference can be attributed to differences in refractive index alone, resulting from organicmatter enrichment during the HBA period.

Two techniques based on synergistic in-situ and ground-based remote sensing instrumentation to retrieve the vertical structure of the atmospheric boundary layer (ABL) and the aerosol mass concentration from the LIDAR extinction are presented. The vertical structure of the ABL during day and night is retrieved by applying the Temporal Height Tracking algorithm to the backscatter and Doppler velocity LIDAR profiles; the calculation of the extinction coefficient from LIDAR returns in combination with in-situ aerosol measurements allow the characterization and categorization of different aerosol layers as well as the estimate of the aerosol mass concentration profile.

The ambient particulate matter concentrations are assessed using annual simulations for model validation period 2006, and for future time-slice years 2030, 2050 and 2100 under RCP scenario 6.0. Meteorological initial and boundary conditions are procured from ECHAM5-HAMMOC global simulations. The contribution of natural and anthropogenic processes to aerosol concentrations are assessed with particular emphasis on accumulation mode sea salt, organic enrichment thereof and future levels of secondary organic aerosol from isoprene.

Clean-air policies in developing countries have resulted in reduced levels of anthropogenic atmospheric aerosol pollution. Reductions in aerosol pollution is thought to result in a reduction in haze and cloud layers, leading to an increase in the amount of solar radiation reaching the surface, and ultimately, an increase in surface temperatures. There have been many studies illustrating coherent relationships between surface solar radiation and temperature however, a direct link between aerosol emissions, concentrations, and surface radiation has not been demonstrated to date. Here, we illustrate a coherence between the trends of reducing anthropogenic aerosol emissions and concentrations, at the interface between the North-East Atlantic and western-Europe, leading to a staggering increase in surface solar radiation of the order of ∼20% over the last decade.

Regional climate model REMOTE is employed to assess the impact of two new sources of marine aerosol precursor vapours (DMS and volatile organo-iodine vapours) on the aerosol population. Microphysical model M7 is applied within REMOTE to simulate gas to particle conversion processes. Results indicate new ultra-fine particle production of the order of 103 particles cm−3 in the North East Atlantic, predominantly due to the nucleation of iodinecontaining vapours. The consideration of DMS vapours in the model leads to an increase in sulphur gases (factor of 1.5-2) which is of sufficient magnitude to enhance the growth of accumulation mode particles over the model domain, the resulting effect on the radiative properties of the atmosphere of potential global significance.

In this study we assess the future ambient levels of isoprene and isoprene SOA for the years 2006, 2030, 2050 and 2100 using a regional climate model. The model is initiliased and boundary values are given by the output of a global model (ECHAM5-HAM–MPIOM-HAMMOC. A key focus point of this study is the variation in particular matter loading with changing meteorology due to climate change.

Formation and growth of aerosol particles during two international field campaigns have been analyzed. Aerosol particle size distributions measured using DMPS data are used together with five simple equations to obtain concentrations of condensable vapor, 3 nm and 1 nm size particles as well as to obtain source rate of condensable vapor. For this analysis the measured growth rates, condensational and coagulational sinks are needed.