ToolsContaminated LandChemistry

PAH Profiling Tool

Compare soil PAH fingerprints against reference source profiles using cosine similarity. Identify coal tar, creosote, diesel, vehicle exhaust, and coke oven sources from 16-EPA PAH data.

Last updated 27 October 2026

About this tool

Compare a soil sample’s 16-EPA PAH fingerprint against five reference source profiles using cosine similarity. Enter PAH concentrations and the tool normalises the profile, calculates similarity scores to coal tar, creosote, diesel/petroleum, vehicle exhaust, and coke oven reference patterns, and ranks the most likely source.

Also calculates four Yunker et al. (2002) diagnostic ratios to distinguish petrogenic from pyrogenic sources. The combination of profile matching and diagnostic ratios gives the most defensible source apportionment result.

A free alternative to commercial PAH profiling tools. Reference profiles compiled from Stout et al. (2001, 2004), Wang et al. (1999), and Ravindra et al. (2008).

How to use this tool

1. Enter PAH concentrations — in mg/kg for each of the 16 EPA priority PAHs. At least 6 non-zero values are needed.

2. View the best match — the tool ranks all five reference sources by cosine similarity score.

3. Check diagnostic ratios — four Yunker ratios classify your sample as petrogenic, pyrogenic, or mixed.

Technical information

Cosine similarity = (A · B) / (|A| × |B|)

Diagnostic ratios per Yunker et al. (2002): Fla/(Fla+Py), An/(An+Phe), BaA/(BaA+Chr), IcP/(IcP+BgP)

Reference profiles are normalised midpoint values compiled from published environmental forensics literature. Scores >0.95 indicate a strong match, >0.90 a good match, <0.80 a poor match.

Limitations

Reference profiles are representative averages compiled from published literature. Real-world source materials vary by geography, product, and weathering state. Site-specific reference materials should be used where available.

Weathering and biodegradation preferentially remove lighter PAHs (naphthalene, acenaphthylene), which can shift the profile toward heavier compounds and reduce similarity to the unweathered reference.

Mixed contamination from multiple sources will produce intermediate profiles that may not closely match any single reference. Consider the diagnostic ratios alongside the profile match for mixed-source scenarios.

Revision history

27 October 2026: Initial release

Disclaimer

This tool is provided for educational and general information purposes only. It is not a substitute for professional engineering advice, design or verification.

Diggy and its contributors are not licensed engineering consultants and no results generated by this tool should be used directly for construction, design or safety-critical decisions.

All values and outputs are based on published empirical correlations and should be independently checked and confirmed by a qualified geotechnical engineer before use.

By using this tool, you accept full responsibility for how you interpret and apply the information provided.

Spotted an error? Let us know.

PAH Concentrations (mg/kg)

Enter concentrations for the 16 EPA priority PAHs. At least 6 non-zero values are required.

Nap

Acy

Ace

Phe

Fla

BaA

Chr

BbF

BkF

BaP

IcP

DBA

BgP

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