Industrial emissions: seeing the invisible to take action

Industrial emissions: seeing the invisible to take action

 

By Olivier Rezazgui, Researcher,  Innofibre. 

 

In an increasingly industrialised and interconnected world, environmental issues are becoming more and more important as the years go by. Among these issues, air quality is undoubtedly the major challenge of the 21st century: it was at the centre of discussions at the Paris Agreement in 2015¹, COP 29 in Baku in 2024, and is the focus of IPCC reports.² it is also central to nations’ economic development plans, as demonstrated by Canada’s 2030 emissions reduction plan.³ And from a purely Canadian perspective, air quality is a hot topic: forest fires in Western Canada, the smoke from which can be felt as far away as Quebec and the United States; controversy surrounding industrial emissions (e.g., Horne Smelter). This is why the analysis of atmospheric emissions is an essential yet little-known science, whose economic and environmental impacts are still often underestimated.

Analysing atmospheric emissions is like checking the ingredients of a dish in a top restaurant: we try to determine what is in it, in what proportions, and whether certain ingredients are undesirable and/or may have an impact on health, the climate, the environment, etc. This information is required in many contexts, the best known of which are:

 

– Complying with legal requirements: each country and/or province imposes strict limits on the emission of certain regulated substances into the atmosphere (e.g. dioxins, furans, formaldehyde, particulates, etc.).

– Protecting the environment and health: some gases contribute to global warming, while others impair air quality and cause respiratory problems; and some substances formed during combustion are toxic or even carcinogenic.

– Optimise industrial processes. Analysing the atmospheric emissions of a given plant provides valuable information on combustion efficiency, ultimately enabling losses to be reduced, energy efficiency to be improved and even the risk of equipment failure to be reduced.

 

Among the substances emitted, the following are the main regulated gases:

 

• CO – Carbon monoxide: colourless, odourless gas that is toxic to humans.

• CO_₂ – Carbon dioxide: the main greenhouse gas produced by humans.

• NO_ₓ – Nitrogen oxides: contribute to smog (smoke) and acid rain.

• SO_x – Sulphur oxides: irritants and precursors of fine particles.

• VOCs – Volatile organic compounds: a family of substances with multiple effects (cancer, lung disease, etc.). Among the most important are benzene, formaldehyde and hydrocarbons (e.g. methane – CH₄).

• Dust / PM10 / PM2.5: inhalable particles that can penetrate deep into the lungs.

• Dioxins and furans: toxic compounds, often present in trace amounts.

As it is impossible to control emissions from mobile sources (vehicles) or natural sources (volcanoes, forest fires) due to the wide variety of emitters, their dispersion across the territory and the unpredictability of emissions (natural sources), control and analysis efforts focus on fixed sources (chemical plants, cement factories, waste incinerators, industrial boilers, etc.). These sources emit emissions at specific points, often through chimneys, which allows for localised and representative sampling of the substances released into the atmosphere.

 

In 2023, the main anthropogenic sources responsible for the majority of air pollutant emissions in Canada were: gas and mining industries (SOx and NOx), agriculture (NH3) and, finally, transport (volatile organic compounds or VOCs).⁴ It is important to measure these emissions in order to take appropriate corrective action. In Quebec, these measures, as well as the maximum permissible concentrations, are regulated by the Ministry of the Environment through the Air Quality Regulation (RAA).⁵ This guide includes the analysis protocols to be used in the laboratory, the location of sampling ports for sampling, and the type of equipment to be used.

 

lthough there is a plethora of portable probes and analysers capable of determining gas concentrations in emissions, in the context of official sampling campaigns, it is necessary to be able to measure standard gas emissions (O₂, CO, CO₂, NOx, SOx, etc.) as well as certain more exotic compounds (dioxins/furans, formaldehyde, etc.) and particulate emissions. This requires the use of a comprehensive emission sampling system, such as the APEX system (APEX Instrument) (Figure 1).

 

This type of equipment generally consists of several components:

 

• A sampling probe (1), inserted into the duct or chimney via sampling ports (the location of which is defined by the RAA⁶ guide), used to capture gases and other particles. It is made of heat- and corrosion-resistant material (stainless steel, titanium, or quartz) and can be heated to prevent the condensation of volatile compounds (VOCs).

• A primary filtration zone (2) that captures particles (isokinetic sampling). To protect them from moisture, the filters, usually made of fibreglass, are stored in an oven before being installed for testing.

• A heated transfer line (3): simply a flexible PTFE tube, heated along its entire length to convey the gases to the collection areas and thus prevent premature condensation.

• Traps/collection areas (4): these are glass bottles, cooled by an ice bath to condense and collect the gases. Depending on the gases to be analysed, the bottles may contain reagents that specifically trap one or more particular compounds (e.g. DNPH for formaldehyde; XAD-2 resins for dioxins/furans, etc.).

• The system also includes a console (5) for measuring and controlling the flow rate and volume sampled. It also allows the concentrations of certain standard gases (O₂, CO, CO₂) to be monitored.

• Finally, the system is completed by a suction pump (6) that creates the necessary flow rate inside the sampling train.

Once the samples have been taken and the gases collected, they are sent to the laboratory for analysis by HPLC and other GC-MS methods. The results provide operators with a valuable source of information. Factors such as the presence of dioxins/furans or the concentration of CO or particulates will highlight poor combustion in the boiler and, consequently, energy losses. The presence of metals or halogens in emissions will present a high risk of corrosion, and a high particle count will indicate a risk of creosote formation and potential pipe blockage.

Ultimately, atmospheric emissions analyses are much more than just a regulatory requirement: they are a powerful tool for knowledge, control and continuous improvement. By measuring pollutant emissions, they not only ensure legal compliance and avoid penalties, but also assess the real impact on the environment and public health. They provide manufacturers with concrete tools to optimise their processes, improve their energy performance and reduce their emissions. Finally, they promote transparency and social responsibility, strengthening the confidence of citizens, authorities and economic partners. Thus, atmospheric emissions analysis is a key step in reconciling industrial activity, environmental protection and social acceptability.

References:

1          U. Nations, L’Accord de Paris | Nations Unies, https://www.un.org/fr/climatechange/paris-agreement, (accessed August 11, 2025).

2          AR6 Synthesis Report, https://www.ipcc.ch/report/sixth-assessment-report-cycle/, (accessed August 11, 2025).

3          Environnement et changement climatique Canada, Plan de réduction des émissions pour 2030, Environnement et changement climatique Canada, 2022.

4          E. et C. climatique Canada, Émissions de polluants atmosphériques, https://www.canada.ca/fr/environnement-changement-climatique/services/indicateurs-environnementaux/emissions-polluants-atmospheriques.html, (accessed August 11, 2025).

5          architecture de gestion de l’information législative-legal information management system Irosoft, – Règlement sur l’assainissement de l’atmosphère, https://www.legisquebec.gouv.qc.ca/fr/document/rc/Q-2,%20r.%204.1, (accessed August 13, 2025).

6          Guay, M., Lecours, M., and Pelletier, L., 2014, 460.