Dirty Scrubbers Continue to Increase Air Pollution

October 23, 2023
Public Relations

Dirty Scrubbers Continue to Increase Air Pollution

If you’ve been keeping up with us, you know that dirty scrubbers have been installed on more than 4,000 ships as a way to circumvent the 2020 IMO Sulphur Fuel Limit, which was implemented to reduce SOx emissions. While we have focused and will continue to focus on the severe impact that these toxic scrubbers have on the marine ecosystem and their contribution toward increasing ocean pollution, it is important that we also concentrate on the effects these polluting scrubbers are having on air pollution and terrestrial ecosystems.

The claim that these awful scrubbers have reduced air pollution is continuously being debunked thanks to several studies analyzing SOx, NOx, CO2, and other harmful greenhouse gas emissions.

The Research

In a 2020 study from The International Council on Clean Transportation (ICCT), it was revealed that there was a 70% increase in particulate matter emissions, an 81% increase in, specifically, Black Carbon emissions and a 4% increase in CO2 emissions produced from scrubber-equipped vessels using Heavy Fuel Oil (HFO) compared to non-scrubber-equipped vessels using Marine Gas Oil (MGO), which has a lower sulphur fuel content.

Additional studies have shown that though SOx emissions have been drastically reduced thanks to the Global Sulphur Cap, ships equipped with these polluting scrubbers still produce large amounts of SOx and NOx emissions. In a 2023 study, the results showed that Ocean Going Vessels (OGVs) with toxic scrubbers not only had significantly higher amounts of non-compliance, at 7% compared to 2% for non-scrubber-equipped OGVs, but were equally emitting substantially higher levels of SO2 to such degree that a 7% increase in SO2 emissions is anticipated by 2030. Moreover, the same study determined the average NOx emissions produced from scrubber-equipped vessels to be 14.4 grams/kiloWatt-hour compared to 13.1 grams/ kilowatt-hour from non-scrubber-equipped ships.

This study revealed that ships with harmful scrubbers overall increase SO2 emissions, NOx emissions, and have operational issues requiring immediate attention.

Why This Matters

Particulate matter is composed of black carbon, sulfates, nitrates, ammonia, sodium chloride, mineral dust, and water. Black carbon, alone, contributes to a myriad of issues for our environment and our health. Since particulate matter is small in size, it can easily find its way deep into our lungs and bloodstream, causing cardiovascular and respiratory diseases, and also results in premature death. Since black carbon is the most solar energy-absorbing component of particulate matter, it can absorb one million times more energy than CO2. This means that it contributes heavily to climate change, warming the planet rather than helping to reflect the sunlight and cool it.

Similarly, SOx and NOx emissions contribute to cardiovascular and respiratory diseases such as emphysema, bronchitis, and asthma, and additionally, to smog and acid rain. Acid rain leaches harmful chemicals and elevates acidification by stripping nutrients, killing trees, other plants, and animals. Needless to say, these harmful emissions threaten the well-being of all Earth inhabitants.

While guidelines on scrubber installations have been updated to increase compliance and emissions monitoring, continuing to install these dirty scrubbers won’t reduce SOx emissions. Clearly, they are not helping to reduce overall air emissions like they claim, increasing both air and ocean pollution.

Again, the only solution to this problem is to ban them altogether!


        “Assessment of the Effect of International Maritime Regulations on Air Quality in the Southern North Sea.” [Published in Atmosphere in June 2023].

        Reduction in greenhouse gas and other emissions from ship engines: Current trends and future options - ScienceDirect ·

        Air emissions and water pollution discharges from ships with scrubbers - International Council on Clean Transportation (theicct.org)

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