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Pasquill Dispersion Class Table

Look up the original Pasquill dispersion table using measured wind and day/night categories, preserving intermediate classes and blank cells.

Use this result well

Inputs that matter
Wind speed at approximately 10 m (m/s), Insolation and cloud category, Sources and assumptions
Output to expect
Original Pasquill dispersion classes
  • Check the units and required inputs before comparing results.
  • Keep the assumptions with a copied result so you can reproduce the calculation later.
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Reference & details

How it works

Original Pasquill dispersion classes

Look up EPA table 6-2 using approximately 10 m surface wind and the specified insolation/cloud category. Preserve intermediate classes and unsupported night cells. This historic dispersion table is not a convective sounding or aviation-safety classification.

Table lookup by wind interval and day/night category; fully overcast conditions use class D.

Updated: September 2026

Example Scenarios

Inspect the example and its input basis, then substitute your own documented measurements or matched cases.

Wind speed at approximately 10 m (m/s): 4Insolation and cloud category: moderate

→ Pasquill class B–C

Common Mistakes to Avoid

Mixing observation and model inputs

Use the exact units, timestamp, level and measurement or model basis stated by the selected mode. A similar quantity from another instrument or product is not automatically interchangeable.

Treating an illustrative case as a measurement

Replace the example with your own sourced inputs. Retain missing values and method limits, and keep raw source data alongside a saved calculation.

FAQ

Look up EPA table 6-2 using approximately 10 m surface wind and the specified insolation/cloud category. Preserve intermediate classes and unsupported night cells. This historic dispersion table is not a convective sounding or aviation-safety classification.

Retain the station or profile identity, observation or issue/valid time, measurement units, quality flags, source and stated method. Missing values, trace precipitation and known zeros have different meanings.

Save weather case keeps an explicit local record. Copy MD includes current inputs and notes; Download CSV includes the current result breakdown. Keep portable copies separately and retain raw source data.

About Pasquill Dispersion Class Table

Look up EPA table 6-2 using approximately 10 m surface wind and the specified insolation/cloud category. Preserve intermediate classes and unsupported night cells. This historic dispersion table is not a convective sounding or aviation-safety classification.