ScentMetrics

OdorControl • Expertise Report

ISO 17025 • EN 13725 • EN 16841

CASE FILE : ODOR-2026-ALPHA-042

I. Introduction and Audit Scope

The olfactometric audit of the Nord-Alpha industrial site was conducted following an increase in complaints from the neighboring residential area. This report presents a multidimensional analysis combining source sampling, atmospheric dispersion modeling, and technical recommendations.

II. Mapping of Emission Sources

Satellite visualization of identified critical points (Wind speed: 3.5 m/s).

SOURCE A : Reception
SOURCE B : Biofilter
SOURCE C : Settling

Zone A (Critical)

Sulfur compounds and volatile organics. Concentration: 4500 uoE/m³. Major impact on neighborhood.

Zone B (Controlled)

Residual humus odor after biofiltration. Non-nuisance at property boundary.

III. Dynamic Plume Modeling

Simulation of odor range under dominant meteorological conditions (Pasquill stability class D).

Perception Legend:
Strong perception (>5 uoE/m³)
Occasional perception

IV. In-Depth Metrological Diagnosis

Gas chromatography-mass spectrometry (GC-MS) analysis revealed the presence of Dimethyl sulfide (DMS) at concentrations of 12 ppb, well above the human perception threshold. This molecule is the primary cause of the "sulfurous" odor signature detected up to 850 m away.

The synergy between sources A and C creates a partial "masking effect" that makes odor source location difficult for untrained olfaction. However, our real-time monitoring isolated an emission peak between 4-6 AM, correlated with the Warehouse A unloading cycle.

V. Strategic Recommendations