As temperatures, dropped on Leeside on the evening of Monday, December 2, household fires were lit and as the evening wore on, weather conditions combined with the city’s unique topography to trap smoke in the river valley which runs west-east between the city’s bridges.

The silent network of 12PurpleAir devices which have been monitored since June by a team of experts in Cork City Council and UCC sent their air pollution data via wifi to the PurpleAir website, which is visible to the world.

They identified a significant spike in harmful invisible PM2.5 particles in the air that can be inhaled deep into the lungs, and which have been linked to premature death.

The devices gave Cork an Air Quality Index (AQI) rating of 156 — more than double the AQI rating for London and more than triple the rating for Rome at the time.

It was this pollution spike that made the headlines around the world, prompting calls for the introduction of flood-alert style air-quality warnings, as well as nd for suggestions that we end our romantic association with the open fire and consider the introduction of “no-burn nights” when certain weather conditions result in a ban on the burning of certain solid fuels.

Kevin Ryan, an executive scientist at Cork City Council who’s involved in the PurpleAir pilot project, said while the pollution spike was concerning, it must be viewed in context.

The levels were probably no worse than any other large urban area in Ireland that night and made headlines simply because the data is now being recorded in such detail in Cork by the PurpleAir network, he said.

“In general, Cork’s air quality is very good in comparison to other large urban centres,” he said.

That assertion is backed by the Environmental Protection Agency’s (EPA) Air Quality Bulletin for November. The daily limit for PM10 is 50ug/metre cubed. The limit is deemed breached if more than 35 exceedances occur during the year.

The EPA data shows one of its hi-tech monitoring stations in Blanchardstown had by the end of last November breached that limit 11 times so far this year, a unit at Davitt Road in Dublin 2 recorded 15 breaches, while a unit at Ringsend recorded 12 breaches.

Its station in Enniscorthy Town recorded 12 breaches.

By contrast, an EPA unit on Cork’s South Link Roadrecorded eight breaches, mostly due to emissions from traffic, a unit at Cork Institute of Technology recorded three breaches, while one in Heatherton Park, near Tramore Valley Park, and another in Cobh, have yet to record a breach of the limits this year.

Mr Ryan said that data shows that if other Irish towns or cities were measuring air pollution in as much detail as Cork is now through the PurpleAirnetwork, they would most likely have shown spikes in the levels of PM10 and PM2.5 on December 2 also.

John Sodeau, emeritus professor of chemistry at UCC and a lead researcher at UCC’s Centre for Research into Atmospheric Chemistry (Crac), has been a vocal campaigner on this issue for years.

He said while the Cork air pollution spike made headlines, it should not come as a surprise given that EPA data earlier this year which showed that pollution had breached safe levels more often in 2019 this year than in the whole of 2018 at most Irish air quality monitoring stations managed by the EPA.

By the middle of the year 2019, the EPA said figures showed there were 84 air-pollution breaches at its stations across the State in the first five months of this year compared to just 17 in the whole of 2018. Twelve of those breaches were in Enniscorthy alone.

Prof Sodeau described Enniscorthy as “rapidly becoming the New Delhi of Ireland” and said the trends show the need for urgent action.

“The problem with the actions which this, or any Government, must take to combat the twin threats from air pollution and its partner, climate change, is that big changes in our lifestyles will have to take place,” he said.

The answer is, unfortunately, higher taxes and closing down Moneypoint power station and driving electric cars and banning coal burning.

“That will hurt us all.

“Although we know the dangers associated with air pollution because it attacks every cell in our bodies as well as destroying ecosystems, we simply do not want to carry the pain.”

The ban on the marketing, sale, and distribution of bituminous fuel — the smoky coal ban — was first introduced in Dublin in 1990 in response to severe episodes of winter smog that resulted from the widespread use of smoky coal for residential heating.

The ban proved effective in reducing smoke and sulphur dioxide levels and was duly extended. It now applies in 26 cities and towns.

EPA data shows the level PM10 in these areas is lower than in towns where the ban does not apply.

Experts believe that around 350 premature deaths a year have been averted in Dublin since its introduction — that’s almost 10,000 lives in total.

In 2012, the Air Pollution Act was updated to include a ban on the burning of smoky coal and other prohibited fuels in all smoky coal ban low smoke zones (LSZs) to complement the ban on the marketing, sale, and distribution of those fuels in those areas. It meant that even ‘smoky’ fuels bought elsewhere cannot now be burned in an LSZ.

But in reality, enforcing a ban on the burning in an LSZ of smoky coal bought outside the zone is almost impossible to enforce, the authorities accept.

And it’s impossible to prevent smoke from outside an LSZ from drifting into the zone and affecting that area.

Prof Sodeau said there have been a few “trans-boundary incidents” which can contribute to Ireland’s rising air pollution trends.

“Air pollution knows no country boundaries. It is not Brexit, with customs borders being required,” he said.

“It is not true to say we need more research done in assessing sources.

“In Ireland, burning coal of all types, wood, and peat add large amounts of particulate to the air.

“The Department of Environment should start by signing the nationwide smoky coal ban immediately. The health of Irish citizens and climate change come first, not legal niceties.”

While the Crac lab Crac has helped raise public awareness of air quality in Ireland, and now in greater detail in Cork City, air pollution has been monitored in the city since the 1980s.

Until June, it was monitored using four hi-tech units, which cost around €20,000 each, at UCC’s Distillery Fields, at CIT, and in and around Tramore Valley Park, while work is also underway to identify a suitable location on a busy road artery for a new roadside monitor.

They all feed detailed air pollution information into the EPA’s national air monitoring system.

But on foot of requests from city councillors for a more detailed analysis of the city’s air quality, the council teamed up with Crac the CRAC lab to identify a cost-effective solution.

They rolled out a network of the US-made PurpleAir devices which went life in June.

Costing about $300 each, and about the same size as a 33cl drinks can, each device can be bolted to the side of a building and plugged into a power source quickly and easily.

They use a laser to monitor air pollution and feed their data via wifi to the PurpleAir network. Twelve were installed initially, but three more are poised to go live, extending the monitoring network to Glanmire, Blarney, and Ballincollig —all of which fall within the extended city boundary.

Their locations and data is publicly accessible via the purple air website.

Rob Bateman, a landfill gas technician with the city council, summed it up nicely.

“It’s like the Google of air quality monitoring,” he said.

It is the first network of its kind and is providing the most detailed picture of air pollution ever in any Irish city.

Dr Ryan said while these devices are not as accurate as of the larger, more expensive, real-time reference units, they do provide indicative results which will help the city prepare an air-quality plan.

But should we be considering wearing surgical masks, like citizens in Delhi or Toyko?

Not just yet, Dr Ryan says.

“Anyone attending a barbecue would be exposed to more pollutants than what we experienced in Cork on December 2,” he said.

However, But both he and Prof Sodeau agree that the upward trend in national air pollution data shows that urgent action is needed to deal with the problem.

Dr Ryan says the PurpleAir data will help inform the development of public policy, while Prof Sodeau says it is clear that our mindset must change to one that is more appropriate to a “wartime setting”.

“In past wars, the public has been taxed, gone hungry and accepted discomfort,” he said.

Make no mistake — we are in World War III now. It’s not against another country or aliens from Mars. It is against Earth’s defensive response to our technological progress.

“Action must be taken, there is no doubt about that.

“Voting for peacetime governance is not appropriate these days. We must now pay for our inactions over the past 70 years since the last World War. And we need to start now.”

Despite the legal difficulties around enforcement, efforts are being taken to identify and penalise households for air pollution breaches.

Figures from Cork City Council show that it has undertaken 85 inspections to ensure compliance since 2015, and has secured six successful prosecutions in relation to smoky coal offences.