ISO 9223 Zinc Corrosion Rate – LE V4 (Localized Emissions) (2020–2024)

Overview

This dataset represents the modeled first-year atmospheric corrosion rate of zinc based on the ISO 9223 atmospheric corrosivity framework enhanced through the Localized Emissions (LE V4) atmospheric chemistry model.

Corrosion rates were calculated using five-year climatological averages (2020–2024) of:

• Temperature
• Relative Humidity
• Sulfate Deposition
• Chloride Deposition

and enhanced using persistent anthropogenic atmospheric burden indicators derived from global emissions datasets.

The resulting raster provides:

• First-year zinc corrosion rate estimates
• LE-enhanced atmospheric corrosion estimates
• ISO 9223 corrosivity classifications
• Continuous atmospheric corrosion exposure mapping

at approximately 1 km spatial resolution.

Units:

• Micrometers per year (µm/year)

Background

ISO 9223 provides internationally recognized dose-response functions for estimating atmospheric corrosion rates of engineering materials using climatic and pollutant exposure variables.

The Zinc LE V4 framework extends the baseline ISO 9223 methodology by incorporating persistent anthropogenic atmospheric burden indicators associated with industrial, transportation, combustion, and urban atmospheric environments.

The LE framework is intended to identify environments where long-term atmospheric pollution conditions may elevate atmospheric corrosion behavior beyond climatology-only estimates.

These classifications are widely used for:

• Galvanized steel durability assessments
• Corrosion engineering
• Atmospheric exposure analysis
• Asset integrity management
• Protective coating selection
• Industrial environmental screening

Localized Emissions (LE V4) Framework

The LE V4 framework enhances the baseline ISO 9223 atmospheric corrosion model using persistent anthropogenic atmospheric burden indicators derived from EDGAR global emissions datasets.

The framework evaluates:

• Acid Gas Burden
• Particulate Burden
• Chemistry Burden
• Total Atmospheric Burden

using pollutant groups including:

• SO₂
• NOx
• PM10
• PM2.5
• BC
• OC
• NH₃
• CO
• NMVOC

The enhancement framework incorporates:

• Atmospheric burden normalization
• Industrial atmospheric chemistry interpretation
• Zinc-specific atmospheric chemistry weighting
• Material-dependent corrosion response behavior

The LE framework is enhancement-only:

• LE can increase corrosion estimates.
• LE does not reduce baseline ISO 9223 predictions.
• LE does not replace ISO 9223.
• LE does not represent pollutant concentrations, emissions inventories, or atmospheric dispersion modeling.

Different metals exhibit differing sensitivity to atmospheric chemistry environments; therefore LE enhancement behavior varies among steel, zinc, aluminum, and copper.

ISO 9223 Zinc Dose-Response Function

The baseline ISO 9223 zinc corrosion model is:

math r_{corr} = 0.0129 \cdot P_D^{0.44} \cdot e^{(0.046RH + f_{Zn})} + 0.0175 \cdot S_D^{0.57} \cdot e^{(0.008RH + 0.085T)}

where:

math f_{Zn} = 0.038(T - 10) \quad \text{if } T \leq 10^\circ C

math f_{Zn} = -0.071(T - 10) \quad \text{if } T > 10^\circ C

The resulting baseline corrosion estimate is subsequently enhanced using the LE V4 atmospheric chemistry framework.

Variable Definitions

The reader is referred to the official ISO 9223 standard for additional material-specific equations and atmospheric corrosivity methodologies.

ISO 9223 Corrosivity Categories (Zinc)

Engineering Interpretation Classes

For visualization and continuous raster interpretation, the following intermediate classes are provided:

These intermediate classes are not part of the ISO 9223 standard and are provided solely for GIS visualization and continuous corrosion exposure interpretation.

LE Framework Development

The LE V4 framework was developed using:

• CORRAG atmospheric exposure datasets
• MICAT atmospheric exposure datasets
• ASTM STP1239 atmospheric corrosion datasets
• EDGAR anthropogenic emissions datasets

Model evaluation incorporated:

• Historical emissions reconstruction
• Leave-one-out (LOO) regression analysis
• Residual analysis
• Atmospheric burden normalization
• Spatial uplift assessment

Representative predictive performance for the ISO 9223 + LE framework:

Interpretation Notes

Lower corrosion rates are typically associated with:

• Arid climates
• Inland environments
• Low humidity regions
• Low pollutant exposure
• Cold dry climates

Higher corrosion rates are typically associated with:

• Marine environments
• Coastal exposure
• Humid tropical climates
• Elevated chloride deposition
• Elevated sulfate deposition
• Persistent atmospheric pollution burden
• Industrial and petrochemical environments

Zinc corrosion behavior is particularly sensitive to:

• Chloride-rich marine atmospheres
• Sulfur-containing pollutants
• Persistent moisture exposure
• Industrial atmospheric chemistry environments

The LE enhancement framework is intended to identify environments where persistent atmospheric chemistry conditions may contribute to elevated corrosion behavior relative to climatology-only estimates.

Spatial Resolution

Data Sources

Primary atmospheric corrosion datasets include:

• NOAA Integrated Surface Database (ISD)
• NASA MERRA-2 Atmospheric Reanalysis
• EDGAR v8 Global Air Pollutant Datasets
• ERA5 Climate Reanalysis and Wind Analytics

EDGAR pollutant groups incorporated into the LE framework include:

• SO₂
• NOx
• PM10
• PM2.5
• BC
• OC
• NH₃
• CO
• NMVOC

Intended Applications

This dataset may be used for:

• Atmospheric corrosion assessment
• Galvanized steel durability analysis
• Protective coating selection
• Asset integrity management
• Industrial atmospheric exposure assessment
• Corrosion engineering
• GIS visualization
• Enterprise API workflows

Related Datasets

Primary Corrosion Layers

• ISO 9223 Steel Corrosion Rate
• ISO 9223 Zinc Corrosion Rate
• ISO 9223 Aluminum Corrosion Rate
• ISO 9223 Copper Corrosion Rate

Enhanced LE (Local Emissions)Corrosion Layers

• ISO 9223 Steel LE V4
• ISO 9223 Zinc LE V4
• ISO 9223 Aluminum LE V4
• ISO 9223 Copper LE V4

Atmospheric Burden Layers

• EDGAR Total Burden
• EDGAR Acid Gas Burden
• EDGAR Particulate Burden
• EDGAR Chemistry Burden
• EDGAR Dominant Emissions Component

Supporting Environmental Layers

• Mean Chloride Deposition
• Mean Sulfate Deposition
• Mean Annual Temperature
• Mean Relative Humidity
• Time of Wetness (TOW)

Supporting Coastal & Terrain Layers

• Distance to the Nearest Coast
• Bathymetry 2024 – Terrain Elevation
• WindRIX Terrain–Wind Exposure Index
• Wind Resultant Direction (0–360°)
• Wind Speed

Attribution

Joseph Mazzella
AtmosphericIQ LLC
Engineering Director, Inc.

Dataset Citation

Mazzella, J. (2026). ISO 9223 Zinc Corrosion Rate – LE V4 (Localized Emissions) Raster (2020–2024). AtmosphericIQ LLC / Engineering Director, Inc.

Standards Citations

ISO 9223:2012. Corrosion of metals and alloys — Corrosivity of atmospheres — Classification, determination and estimation. International Organization for Standardization (ISO).
https://www.iso.org/standard/53499.html

ISO 12944-2. Paints and varnishes — Corrosion protection of steel structures by protective paint systems — Part 2: Classification of environments. International Organization for Standardization (ISO).
https://www.iso.org/standard/64834.html

Supporting Dataset Citations

Crippa, M., Guizzardi, D., Solazzo, E., et al. EDGAR v8 Global Air Pollutant Emissions. European Commission Joint Research Centre (JRC).
https://edgar.jrc.ec.europa.eu/

NASA Global Modeling and Assimilation Office (GMAO). MERRA-2 Atmospheric Reanalysis Dataset.
https://gmao.gsfc.nasa.gov/reanalysis/MERRA-2/

NOAA National Centers for Environmental Information (NCEI). Integrated Surface Database (ISD).
https://www.ncei.noaa.gov/products/land-based-station/integrated-surface-database

Version Information