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PEF shortens this to Acidification and expresses results in mol H⁺ eq rather than the kg SO₂ eq used by ReCiPe 2016. Both quantify acidifying emissions; the unit differs because PEF uses hydrogen ion equivalents instead of sulfur dioxide.

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Definition

Acidification Potential (AP) measures the ability of a substance to form acid rain, fog, and snow by releasing hydrogen ions into the environment. It is expressed in kilograms of sulfur dioxide equivalent (kg SO₂ eq.) using ReCiPe 2016 characterization factors.

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Environmental Mechanism

Acidification occurs when acidifying pollutants such as sulfur dioxide (SO₂), nitrogen oxides (NOx), and ammonia (NH₃) are converted to acids after being released into the atmosphere. These acids fall as precipitation or deposit directly onto surfaces, causing:
  • Soil acidification
  • Freshwater acidification
  • Damage to forests and vegetation
  • Corrosion of buildings and infrastructure
  • Reduced biodiversity in sensitive ecosystems
  • Leaching of toxic metals from soil into water bodies

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Calculation in GREENZERO Journey

GREENZERO Journey calculates AP by:
  1. Identifying all acidifying emissions associated with a product throughout its lifecycle
  2. Converting each emission to its SO₂ equivalent using characterization factors from ReCiPe 2016
  3. Summing all SO₂ equivalents to determine the total AP
About ReCiPe 2016ReCiPe 2016 is a life cycle impact assessment (LCIA) method that provides characterization factors for converting inventory data into environmental impact indicators. It is not a methodology itself, but rather a comprehensive database of impact assessment factors developed by Dutch research institutes.The method provides characterization factors that translate emissions and resource use into standardized impact units (e.g., kg CO₂ eq. for climate change, kg SO₂ eq. for acidification). GREENZERO Journey follows ISO 14040/44 methodological standards while using ReCiPe 2016 characterization factors for impact calculations.

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Environmental Cost Conversion

The AP impact is converted to environmental cost using the CE Delft cost factor: CE Delft Cost Factor for AP: €5.27 per kg SO₂ eq. This factor represents the societal cost of damage from acidification, including:
  • Ecosystem damage
  • Agricultural yield losses
  • Infrastructure deterioration
  • Human health impacts from respiratory issues
  • Reduced biodiversity

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Example Calculation

For a product with an AP of 0.5 kg SO₂ eq. per piece: 
Environmental Cost = AP × CE Delft Factor
Environmental Cost = 0.5 kg SO₂ eq. × €5.27/kg SO₂ eq.
Environmental Cost = €2.64 per piece

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Interpretation

Acidification impacts are typically more localized than global warming impacts but can be severe in affected areas. Key contributors to AP in product lifecycles typically include:
  • Combustion of fossil fuels (especially coal and heavy oil)
  • Industrial processes
  • Agricultural activities (particularly livestock farming)
  • Transportation emissions
  • Electricity generation

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Reduction Strategies

Common strategies to reduce AP include:
  • Fuel switching to lower-sulfur options
  • Emission control technologies (scrubbers, catalytic converters)
  • Process optimization
  • Reduced fertilizer use in agriculture
  • Energy efficiency improvements
  • Renewable energy sourcing

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Data Quality Considerations

When interpreting AP results, consider:
  • Regional sensitivity to acidification varies significantly
  • Emission location is particularly important for this impact
  • Temporal aspects of emissions
  • Background deposition levels in affected areas
AP often correlates with other impact categories, particularly:
  • Eutrophication Potential
  • Photochemical Ozone Creation Potential
  • Human Toxicity Potential

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References

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