Plume Sentinel

Atmospheric hazard dispersion viewer

An interactive, browser-native tool for seeing where a dispersing plume becomes dangerous — and by how much — tuned in real time.

Model validity: a steady-state Gaussian plume for flat, open (rural) terrain and a continuous, constant-rate release — most reliable within roughly 10–20 km downwind. Uses rural Briggs σy/σz coefficients; it is not a puff / instantaneous-release model and does not resolve buildings, complex terrain, or street-canyon effects. Positioning: an illustrative training/concept tool for exploring plume shape and sensitivity — not a substitute for operational tools such as ALOHA/CAMEO (emergency response) or AERMOD (EPA regulatory permitting), and not for compliance use.

model: Gaussian plume · Pasquill–Gifford stability (Briggs σy/σz) · ground reflection 3D: —

Scenario preset

Source & meteorology

Emission rate Q Wind speed u Wind direction Release height H Domain length

Atmospheric stability (Pasquill–Gifford)

Urban dispersion coefficients

Switches σy/σz to the Briggs urban-terrain formulation (more mechanical/heat-island turbulence → wider, shallower plume). A coarse literature approximation, not a building-resolved urban-canopy model. Off = rural/open-country coefficients (default).

Concentration bands (µg/m³, ground level) — not time-weighted dose

Safe below

Elevated ≥

Unhealthy ≥

Hazardous ≥

Extreme ≥ Hazardous

Real AEGL/ERPG/AQI exposure limits are defined over specific averaging windows (10 min – 8 hr); a single instantaneous concentration threshold cannot be validated against them. These bands illustrate plume shape only, not validated dose limits.

Animation

Wind gust animation (breathing plume)

View

2D Plan 3D View Side-by-side

Peak ground-level conc. —

…at downwind distance —

Dangerous (≥ Elevated) within —

Plan view · z = 0 Click to drop a receptor probe

Danger bands — legend, concentration thresholds (not time-weighted dose), and extent along the plume centerline
	Band	Threshold	Extends to
	Safe	—	—
	Elevated	—	—
	Unhealthy	—	—
	Hazardous	—	—
	Extreme	—	—

What would make this operational?

A real basemap + geocoding, so downwind/crosswind coordinates correspond to actual streets, facilities, and populated places (this prototype uses an abstract plan view with no geographic reference).
Live wind observations feeding speed/direction, instead of a user-set constant wind.
A validated chemical/AEGL·ERPG library with proper exposure-time windows (10-min/30-min/60-min/4-hr/8-hr), replacing the single illustrative concentration thresholds used here.
A population-exposure layer (e.g. census or LandScan-style density) to estimate people affected, not just plume area.