SCIENTISTS from 20 research institutions working at Mace Head near Carna in Connemara have found high formaldehyde levels over the sea, confirming pollution that coincides with high ozone levels.
Based at UCG's Atmospheric Physics Research Station, the study is part of a five-year global experiment to establish why ozone gas levels in the lower levels of the remote marine atmosphere have trebled over the past century and how it is changing our climate.
The team of 40 environmental scientists may soon provide a definitive indication of how pollution is damaging the atmosphere nearest the Earth's surface, particularly above the seas of the northern hemisphere.
Their recording of climatic readings over the past six weeks from a remote weather station in Connemara is helping to fill in the information gap.
Ozone was once regarded as being therapeutic because of its germicidal properties and was linked to the health-giving affects of sea air. The feel-good factor is probably due to other causes, however - ozone, a highly reactive form of oxygen, can inflame lungs and damage eyes.
The likely role of pollution in upsetting the troposphere, the part of the atmosphere between the ground up to about five miles, is being examined. Pollutants from motor vehicles and electricity generating stations are believed to be the main culprits.
The complex experiment is concentrated on ozone production and destruction over the sea, particularly in spring when ocean activity is at a maximum. It aims to get a better picture of natural processes and how they are influenced by man-made emissions.
The ozone layer higher in the atmosphere, which absorbs much of the sun's damaging radiation, is of great importance to our well- being. That is why man-made chemicals which erode it are of concern. Closer to the earth however, high ozone concentrations are not so welcome.
Mace Head, a global atmospheric watch station, monitors greenhouse gases including carbon dioxide and ozone damaging chemicals such as CFCs (chlorofluorocarbons) continuously. Of late, chemicals called HCFCs have been replacing CFCs because they are not as destructive to ozone.
Mace Head's unique position in the northern hemisphere was first noted 40 years ago by Dr Tom O'Connor of UCG. The ability to measure relatively clean air over the Atlantic and polluted air from Europe from the one spot gives Mace Head a pivotal role.
Much of the study's focus is on how tropospheric ozone, which warms the environment, is made and lost over the Atlantic and how fine particles, known as aerosols, form in the air from the emission of gases from the ocean and cool the environment. Some aerosols arise because of pollution. Finding the right balance between warming and cooling is important.
Highly sensitive instruments including laser systems, were used to measure minute concentrations of atmospheric particles and gases, which are so reactive that they must be analysed in situ. They cannot he put in a can and brought to a laboratory.
The study also used radiosondes (weather monitoring balloons released into the atmosphere), a research vessel which recorded data at sea and special aircraft to monitor the atmosphere.
"These experiments are of equal importance to studies looking at ozone loss from CFC emissions in the stratosphere," according to
Prof Stuart Penkett of the University of East Anglia. In this present case, though, increasing ozone is causing atmospheric warming. Some of the warming is also balanced by a cooling from the aerosols."
He is leading the research with Dr William Struges, also of the University of East Anglia. Atmospheric Chemistry Studies in the Oceanic Environment (ACSOE) is financed by Britain's Natural Environment Research Council, which has committed £5 million. Further support has come from UCG and other international sources.
While similar studies are being pursued in the Pacific and southern oceans, the Carna study `his probably the most extensive study of the chemistry of the atmosphere ever made at one location," Prof Penkett said. Previously, it had been thought that a lot of ozone was coming from the upper atmosphere. In fact, it's due to our own pollution," he said.
Dr Cathy Cahill of the Desert Research Institute, Nevada, who is on a Fulbright scholarship in UCG, is helping to co-ordinate the investigation and focusing on the role of aerosols, "which are fine particles which influence climate and human health" and can contribute to conditions such as asthma and lung cancer.
The station's proximity to relatively clean Atlantic air enables the setting of baseline data - the chemical concentrations suggest very low levels of pollution. There is nowhere any more, however, that can be classified as clean", Dr Sturges said. "Pollutants are coming across the Atlantic. Everywhere in the northern hemisphere is affected by pollution, less so in the southern atmosphere."
Wind direction is a big factor, Dr Cahill said. When the wind blows from mainland Europe - up to 20 per cent of the time - there is significant pollution. It coincides with low rainfall so there is no awash out" of pollutants from the atmosphere.
