Sunday 20 October 2019

Sweltering summer left city dwellers breathless as toxic brown haze threatened public health alert

Fumes: Exhausts are the main issue in large urban areas. Stock picture
Fumes: Exhausts are the main issue in large urban areas. Stock picture

Caroline O'Doherty

Exhaust fumes and other pollutants were cooked together into a choking form of ozone that almost triggered a public health alert during last year's summer heatwave, the Environmental Protection Agency (EPA) has revealed.

The dangerous mix of pollutants, more commonly found in densely packed cities in China, was visible as a dirty brown haze and was thick enough to breach World Health Organisation guidelines at 13 of the 15 air quality stations the EPA used to monitor it.

The problem peaked in June 2018, which was the hottest and, in many places, the driest June in Ireland for 40 years with temperatures hitting 32C on one occasion.

Details of the incident are revealed in the EPA's annual air quality report which is released today to coincide with World Lung Day.

Poor air quality is responsible for 1,180 premature deaths in this country each year, according to the report, with heart attacks, strokes and chronic and acute respiratory conditions all caused by, or exacerbated by, polluted air.

The EPA warns that with more heatwaves expected in the future, the problem could get worse.

Ground ozone, also known as photochemical smog, is caused when the nitrogen dioxide spewed out from petrol and diesel vehicles mingles with emissions from factories, power plants and industrial boilers and the mixture reacts with intense sunlight.

A feature of traffic-congested urban areas, it is very different from the beneficial ozone layer of protective gas that lies many kilometres above the Earth.

According to the EPA, breathing in ground ozone can trigger a variety of health problems including chest pain, coughing, throat irritation and airway inflammation. It also can reduce lung function, damage lung tissue and worsen bronchitis, emphysema and asthma.

In June 2018, concentrations reached 160 micrograms per cubic metre. "If they had reached 180 micrograms per cubic metre, it would have triggered a public information alert," the EPA says.

"This episode showed that ground level ozone is a potential problem pollutant in Ireland if suitable weather conditions are experienced again in the future."

The annual report shows that air pollution levels remained within permitted EU levels at the 57 monitoring stations around the country, but they often breached the higher standards set by the World Health Organisation, which the EPA says are the benchmark that should be aimed for.

Exhaust fumes are the main problem in larger urban areas while many towns across the country, which are not covered by the ban on smoky coal and do not have access to the natural gas network, suffer with smoke and particles from solid fuel fires and stoves.

Dr Micheál Lehane, the EPA's director of environmental monitoring, said the move towards cleaner cars and home heating as envisaged in the Climate Action Plan would have the twin benefits of reducing carbon emissions and improving air quality.

But he warned that until there was substantial progress on those fronts, air quality would continue to suffer and it was expected nitrogen dioxide levels would soon breach EU levels in Dublin.

Recent sampling by both the EPA and Transport Infrastructure Ireland have shown that while nitrogen dioxide levels are technically compliant as they average out below permitted levels over the course of a year, there are breaches on given days.

"Air pollution is a major environmental risk to health so it is now time to tackle the two key issues that impact negatively on air quality in Ireland - transport emissions in large urban areas and emissions from burning of solid fuels," said Dr Lehane.

"The choices we make affect the levels of pollution in the air we breathe."

The Government has promised to extend the smoky coal ban currently in place in the cities to all urban areas. However, the move has been held up in legal wrangles with action threatened if other smoky fuels are not also included in the ban.

A national clean air strategy being developed by the Department of Communications, Climate Action and the Environment is due to be published by the end of this year.

The EPA is also planning to launch a citizen science project on air quality next year, asking interested citizens in Dublin and Cork to deploy air samplers in their local areas to increase the amount of air quality data available for study.

Irish Independent

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