If there were any lingering doubts that the Northern Pulp mill was in a polluting league of its own in Pictou County, a new peer-reviewed study should lay those to rest for once and for all.

The study looked at a several different sets of publicly available data on the concentrations of fine particulate matter in the area between 2004 and 2021, and at the emissions of three large industrial plants near Pictou — the Northern Pulp mill, the coal-fired Nova Scotia Power plant in Trenton, and the Michelin tire plant in Granton.

The study, by Gianina Giacosa, Daniel Rainham and Tony Walker, all at Dalhousie University, found that not only was the Northern Pulp mill responsible for more emissions of fine particulate matter than the other two large industrial facilities in the Pictou area, but that during times of high particulate matter emissions, the pulp mill emitted 10 to 80 times more of the air contaminant than either the power or tire plant.

Night shot of Northern Pulp mill with bright lights illuminating clouds of smoke and steam coming from stacks.
Paper Excellence’s Northern Pulp mill in 2014. Credit: Tony DeCoste Photo-Video

According to Health Canada, fine particulate matter is the name for a range of particles less than 2.5 microns in diameter, hence the acronym PM2.5. For an idea of just how tiny these particles are, the diameter of a human hair is 60 microns, so 24 times larger than PM2.5.

A 2022 Health Canada assessment for PM2.5 states that “air pollution, specifically from ambient (outdoor) fine particulate matter (PM2.5), is one of the leading environmental causes of death and disease both globally and in Canada” and it is linked to 15,300 premature deaths in Canada each year.

In 2013, the World Health Organization classified PM2.5 as “carcinogenic to humans,” saying that it increases the risk of lung cancer. PM2.5 is so tiny it can pass through the throat and nose and penetrate deep into the lungs, even into the blood and brain. PM2.5 is associated with cardiovascular disease and brain damage, including strokes and “changes in cognitive function, dementia, psychiatric disorders, etc.”

You get the picture. Not the kind of thing one wants belching out of smokestacks to clog the air one breathes.

But that is exactly what was happening in the area around Pictou for a decade or more, and the main culprit and source of the PM2.5 was the Northern Pulp mill.

More PM2.5 pollution than the coal-fired plant

According to Tony Walker, associate professor in Dalhousie University’s School for Resource and Environmental Studies, during periods of peak emissions, the particulate matter from the pulp mill was 100 times higher than it was from the coal-fired power generating plant.

In a telephone interview with the Halifax Examiner, Walker said that they used “multiple lines of evidence,” including looking at other pollution measuring stations in Nova Scotia to ensure those did not show the same peak periods of PM2.5 concentrations found in Pictou.

In that way, Walker said, they were able to rule out pollution from forest fires or other sources moving into the province from elsewhere in Canada or from the northeast United States, noting that “Nova Scotia is on the tail pipe of North America.”

An unsmiling man in a black ski jacket in front of a wharf with blue ocean water and treed shoreline in the distance
Dr. Tony Walker Credit: Tony Walker Twitter

A 2022 study undertaken by Walker’s student Gianina Giacosa, and co-authored by Walker, Codey Bennett of Nova Scotia Environment and Climate Change, and Daniel Rainham of Dalhousie University’s School of Health and Human Performance, showed that among nine pulp and /or paper mills in Atlantic Canada, between 2002 and 2019 the Northern Pulp mill was the highest emitter of several pollutants, including fine particulate matter.

Between 2002 and 2015, Northern Pulp emitted an average of 994.4 tonnes of PM2.5 a year, while the average for all the other mills was just 174.1 tonnes.

Related: Northern Pulp is in a polluting league of its own

Related: Dirty Dealing Part 3: Elevated Levels of Cancer-Causing Air Emissions Coming from Abercrombie Pulp Mill, Peer-Reviewed Study Reveals

Related: Dalhousie researcher breaks silence over pulp mill’s cancer-causing air emissions

The new study on PM2.5 levels in the air around Pictou found that the highest concentrations of the carcinogenic pollutant occurred in the spring of 2014 and 2015, and that these occurred before a precipitator was installed to reduce pollution from the Northern Pulp mill stacks in October 2015.

The data showed that levels of PM2.5 recorded by the National Atmospheric Pollution Surveillance (NAPS) station in Pictou only met the “desirable air quality” concentrations after an electrostatic precipitator was installed by Northern Pulp.

“The mill never really achieved or met the targets of the Canadian ambient air quality standards prior to 2016,” Walker told the Examiner. “They only met them after the precipitator was installed. Precipitators are not new technology. They could have done this years ago, decades ago, and it was only after they were mandated to do so after their industrial approval was up.”

Walker noted that the study looked at an 18-year period, which captured emissions 11 years before the new precipitator was installed. Paper Excellence acquired the mill in 2011, so was responsible for four of those years of high emissions before the precipitator was put in, including 2014 and 2015 when the highest concentrations occurred.

The study looked at data until 2021, a year after the Northern Pulp mill went into hibernation after failing to get approval from Nova Scotia Environment for a proposed new effluent treatment facility before it was legislated to close its Boat Harbour facility. This meant the mill had no place to send its effluent after January 2020. Shortly after that, Paper Excellence withdrew its proposal rather than produce the Environmental Assessment Report required by the province’s environment minister.

Paper Excellence responds

The Examiner asked Paper Excellence for a response to the latest study’s findings. We received a statement, which reads in part:

We are aware of Dr. Walker’s study about the industrial impact on air quality, specifically fine particulate matter, in Pictou County. The study was based on data from 2004 to 2016 before a new precipitator was installed that significantly improved air emissions. While we may not fully agree with the positioning of the historical findings, we agree that things need to be done differently if we want to operate the mill again.

Paper Excellence operated Northern Pulp for less than 10 years of the mill’s six decades of operations, and as a result of community input since the shut down of the mill, it is clear to us that tomorrow’s mill operations and processes—from community engagement and transparency to forestry practices and addressing odour, air, and water emissions—must be better than the mill of yesterday.

Paper Excellence is proposing a complete transformation of Northern Pulp. One that would transform the Mill into a best-in-class operation and one of the world’s cleanest, most environmentally and socially advanced mills.  We will be investing in state-of-the-art technology, and, in some cases, installing first-of-its-kind technology in Canada.

In terms of air quality, the proposed transformation will result in no odour, clean air, and no visible plumes above the mill. Among the many new technologies proposed that will lead to improved air quality is the replacement of the power boiler scrubber with a wet electrostatic precipitator which will result in a high-efficiency collection of the fine particulate matter, like those discussed in the study, and contribute to eliminating visible plumes above the mill.

Northern Pulp still enjoying creditor protection

In December 2021, Northern Pulp submitted a proposal to Nova Scotia Environment and Climate Change for a new effluent treatment facility and for the “transformation” of the 58-year old pulp mill.

Related: Northern Pulp says it is insolvent and can’t pay its pension obligations but it’s got plenty of cash to bankroll legal assaults on Nova Scotia’s government and laws

Related: The weird legal mechanism being used by Northern Pulp it ins $450 million lawsuit against Nova Scotia

The previous year, in June 2020, Northern Pulp and six affiliates declared themselves insolvent, and sought creditor protection in the British Columbia Supreme Court under the Companies’ Creditors Arrangement Act.

Because they are under creditor protection, Northern Pulp and its affiliates are not repaying more than $86 million in outstanding debts to Nova Scotia.

Last year, presiding judge Justice Shelley Fitzpatrick agreed to a request from Northern Pulp, and forced the province into closed-door mediation on a $450 million lawsuit that Northern Pulp and Paper Excellence have filed against Nova Scotians in the Nova Scotia Supreme Court.

In its submissions to the British Columbia Court, Northern Pulp continues to pressure the province to allow it to proceed with the construction to revamp the mill and put in a new effluent treatment plant even before the company has submitted the mandatory Environmental Assessment Report for the project to Nova Scotia Environment and Climate Change for a Class II Environmental Assessment.

Why a new study about pollution from a closed mill?

Asked why the results of this new study on PM2.5 concentrations in the air around Pictou are relevant or important, given that the mill has been closed since 2020, Walker replied that personally, he is “sick of being called out by industry,” and “by mill supporters and lobbyists.” He said there has always been “big pushback from the mill” on his and his colleague’s previous papers looking at Northern Pulp’s air pollution, both when it was still operating and now that it’s mothballed.

Walker said the science in those papers was “robust and sound,” and it is important to look at the mill’s “environmental impacts historically.” He continued:

I think it’s still relevant because the mill is litigating the province, claiming bankruptcy, yet it is still poised to reopen the mill … We can’t un-know this data and we can’t un-know the fact that it [the pulp mill] has been flaunting all kinds of regulations, both on the effluent with Boat Harbour but also air quality … We know that it operated outside of the air quality thresholds.

Walker said the technology to reduce pollution existed long before Northern Pulp installed the new precipitator in 2015.

An “Air Emission Management Plan” done by a consultant for Northern Pulp in 2009 noted that the precipitator on the mill’s recovery boiler was “typical” of “that generation (1960’s).”[1] The report also noted that the scrubber to remove particulate matter on the power boiler had been out of commission since 2006.

After the province issued a directive to Northern Pulp to get the scrubber working by November 2012, the mill claimed it had done so. In 2015, the power boiler was still exceeding particulate matter emissions, and the province had to issue another directive to the mill to have it independently evaluated this time.

smoke and steam clouds billowing from four stacks on the Northern Pulp mill, with labels in red lettering indicating the nature of each of the stacks.
Northern Pulp’s five pollution-emitting stacks. Original photo courtesy Gerry Farrell. Credit: Dr. Gerry Farrell

Walker believes the mill’s environmental record seriously harms its “social licence to operate.”

“It’s lost all credibility, both scientifically and with members of the public,” he said. “It claims to be a sustainable industry and being clean and all this kind of stuff. But based on this data and other data which we’ve worked on up to now — and it’s publicly available data, even data that this mill even puts out itself and gets signed off by the government — it should be ashamed of itself.”

And if the mill does ever re-open, Walker said, “It has to be held to account. Its past performance is not impressive.” 

The paper, published in the May 2023 issue of Atmospheric Pollution Research, is accessible to the public for free for 50 days, and available on request to the authors after that.


[1] Pöyry. September 25, 2009. Northern Pulp Nova Scotia Corporation, New Glasgow, Nova Scotia. Air Emission Management Plan.

Joan Baxter is an award-winning Nova Scotian journalist and author of seven books, including "The Mill: Fifty Years of Pulp and Protest." Website: www.joanbaxter.ca;...

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  1. Let me get this straight. After years of obfuscation and denial, NP now agrees “things need to be done differently” – IOW “we did nothing wrong and we promise not to do it again”. AND they’re promising to spend hundreds of millions of dollars to upgrade an 80 year old mill but can’t afford to repay the $86 million they owe the province? If anyone in this province is falling for NP’s BS, please contact me, I’ve got a bridge to sell you.