11 September 2026 · Product and calculation update
The Interactive Explorer now includes the 14-hour tank-shutdown case (LPCF) alongside the historical feed-gas and compressor-maintenance cases. These are reconstructions from the 17 October 2014 design inventory. They are not new current-design estimates or measured flare events.
| Preset | Historical active duration | PM₂.₅ rate (g/s) | PM₂.₅ mass over that duration (kg) |
|---|---|---|---|
| Feed-gas depressurization, WWGF | 30 min | 1.222222 | 2.2 |
| Tank shutdown, LPCF | 14 h | 55.700397 | 2,807.3 |
| MR compressor maintenance, CDGF | 30 min | 263 | 473.4 |
Each rate divides the published maximum daily mass by the listed active duration. The calculation assumes a uniform release over that duration; the source does not supply the actual event timeline. These maxima are distinct cases and must not be summed into one event. The original inventory already includes its stated contingency. Historical source consistency and primary documents.
A new source comparison switches between release rate and total historical event mass for PM₂.₅, NOx, CO and total VOC. The longer LPCF case illustrates why a lower rate can still give a larger total mass. This arithmetic alone does not determine exposure: the duration, weather, heat, plume rise and receptor location all matter.
Download exact input data. NOx is reported as NO₂-equivalent mass and is not automatically ambient NO₂. Total VOC does not identify benzene or other individual compounds. No new current SO₂ or benzene case is introduced.
The elapsed-time and release-duration controls now extend to 24 hours. Shortcuts select one hour, the end of the chosen release, or one day. Selecting a preset restores its historical duration; changing that duration keeps the reconstructed rate fixed and changes total mass. A custom duration is labelled as such, including in the saved result.
A snapshot reports whether the release is ongoing, ends at that time, or ended earlier. The emissions caption distinguishes scheduled total mass from mass emitted through the snapshot. Material already airborne can persist after the source stops. The concentration calculation still uses fixed scenario weather throughout the 24-hour integration; this is particularly consequential for a long event.
Objective comparisons retain their full matching windows: the first 24-hour mean or hourly-block results, as labelled. A snapshot during hour one does not turn a 24-hour objective into a one-hour comparison. The existing chemical-conversion and background qualifications remain.
The plume still uses the browser's illustrative terrain and wind treatment, with a prescribed injection height. It does not use the separate CALMET wind fields. The map displays air-layer means, not a concentration calculated at a person's breathing height. Neither model refinement nor this preset addition establishes a health-risk zone.
The saved wind study remains a dated, separate display of actual CALMET results. New vertical-resolution checks, a comparison with native model vertical motion, and a marine thermal-input audit narrow the research questions. The large vertical-motion discrepancy and local weather limitations have not been resolved, so no new wind configuration is adopted for the plume.
The source comparison also links the existing historical AERSCREEN results. Those use historical heat, synthetic weather and 1.5 m receptors over flat ground. Their normalized 1 g/s coefficients keep each source's full historical heat fixed. The maximum at each distance can come from different assumed weather. Multiplying the coefficient by pollutant rate is fixed-heat mass scaling, not fuel-throughput scaling. The compressor case retains its equivalent-diameter warning.
An independent review passed 320 arithmetic and interface-semantic checks across the three source cases, including the 14-hour release, post-release mass, full-period averages, preset resets and custom-duration labels. The solver and worker are unchanged. Source rates now use full-precision reconstruction instead of rounded intermediate rates. Desktop and mobile browser checks exercised the actual map and comparison controls. These checks establish implementation consistency, not physical validity.
Independent checks, numerical checks, and source-display checks.
The next predictive step still requires a linked current release case with heat and emissions on the same timeline, demonstrated local wind performance and a suitable plume treatment. FortisBC's proposed source rates remain separate evidence because missing geometry prevents a defensible map source. The research plan applies common receptor, pollutant, time-period, background and uncertainty criteria throughout the study area.