Regional Air Quality Deterministic Prediction System (RAQDPS)

The current operational air quality forecast model is GEM-MACH (Global Environmental Multi-scale - Modelling Air quality and CHemistry). This model is a comprehensive air quality model containing a full description of atmospheric chemistry and meteorological processes. GEM-MACH is an in-line model, meaning that the meteorology is integrated in-step with the chemistry. The model uses the emissions inventory to assess the source of tropospheric ozone precursors. GEM-MACH is run twice a day over North America and is used to provide guidance for the production of air quality forecasts for Canadians.

The output over the next 48 hours is shown below for tropospheric ozone near the surface and at altitudes of 50 metres and 500 metres, and for PM 2.5 and PM10 near the surface. Forecasts for PM2.5, PM10, and ozone near the surface and for ozone at 500 metres can be viewed simultaneously on the 4-panel maps.

Maximum ozone near the surface over a 6-hour interval
Eastern Canada Western Canada North America
00 UTC 12 UTC 00 UTC 12 UTC 00 UTC 12 UTC
T+06 T+06 T+06 T+06 T+06 T+06
T+12 T+12 T+12 T+12 T+12 T+12
T+18 T+18 T+18 T+18 T+18 T+18
T+24 T+24 T+24 T+24 T+24 T+24
T+30 T+30 T+30 T+30 T+30 T+30
T+36 T+36 T+36 T+36 T+36 T+36
T+42 T+42 T+42 T+42 T+42 T+42
T+48 T+48 T+48 T+48 T+48 T+48
Animation Animation Animation Animation Animation Animation

Maximum ozone near 50 metres over a 6-hour interval
Eastern Canada Western Canada North America
00 UTC 12 UTC 00 UTC 12 UTC 00 UTC 12 UTC
T+06 T+06 T+06 T+06 T+06 T+06
T+12 T+12 T+12 T+12 T+12 T+12
T+18 T+18 T+18 T+18 T+18 T+18
T+24 T+24 T+24 T+24 T+24 T+24
T+30 T+30 T+30 T+30 T+30 T+30
T+36 T+36 T+36 T+36 T+36 T+36
T+42 T+42 T+42 T+42 T+42 T+42
T+48 T+48 T+48 T+48 T+48 T+48
Animation Animation Animation Animation Animation Animation

Maximum ozone near 500 metres over a 6-hour interval
Eastern Canada Western Canada North America
00 UTC 12 UTC 00 UTC 12 UTC 00 UTC 12 UTC
T+06 T+06 T+06 T+06 T+06 T+06
T+12 T+12 T+12 T+12 T+12 T+12
T+18 T+18 T+18 T+18 T+18 T+18
T+24 T+24 T+24 T+24 T+24 T+24
T+30 T+30 T+30 T+30 T+30 T+30
T+36 T+36 T+36 T+36 T+36 T+36
T+42 T+42 T+42 T+42 T+42 T+42
T+48 T+48 T+48 T+48 T+48 T+48
Animation Animation Animation Animation Animation Animation

PM2.5 near the surface - mean over a 6-hour interval
Eastern Canada Western Canada North America
00 UTC 12 UTC 00 UTC 12 UTC 00 UTC 12 UTC
T+06 T+06 T+06 T+06 T+06 T+06
T+12 T+12 T+12 T+12 T+12 T+12
T+18 T+18 T+18 T+18 T+18 T+18
T+24 T+24 T+24 T+24 T+24 T+24
T+30 T+30 T+30 T+30 T+30 T+30
T+36 T+36 T+36 T+36 T+36 T+36
T+42 T+42 T+42 T+42 T+42 T+42
T+48 T+48 T+48 T+48 T+48 T+48
Animation Animation Animation Animation Animation Animation

PM10 near the surface - mean over a 6-hour interval
Eastern Canada Western Canada North America
00 UTC 12 UTC 00 UTC 12 UTC 00 UTC 12 UTC
T+06 T+06 T+06 T+06 T+06 T+06
T+12 T+12 T+12 T+12 T+12 T+12
T+18 T+18 T+18 T+18 T+18 T+18
T+24 T+24 T+24 T+24 T+24 T+24
T+30 T+30 T+30 T+30 T+30 T+30
T+36 T+36 T+36 T+36 T+36 T+36
T+42 T+42 T+42 T+42 T+42 T+42
T+48 T+48 T+48 T+48 T+48 T+48
Animation Animation Animation Animation Animation Animation

4-panel maps (PM2.5, PM10, O3 near the surface, O3 near 500 metres)
Eastern Canada Western Canada North America
00 UTC 12 UTC 00 UTC 12 UTC 00 UTC 12 UTC
T+06 T+06 T+06 T+06 T+06 T+06
T+12 T+12 T+12 T+12 T+12 T+12
T+18 T+18 T+18 T+18 T+18 T+18
T+24 T+24 T+24 T+24 T+24 T+24
T+30 T+30 T+30 T+30 T+30 T+30
T+36 T+36 T+36 T+36 T+36 T+36
T+42 T+42 T+42 T+42 T+42 T+42
T+48 T+48 T+48 T+48 T+48 T+48
Animation Animation Animation Animation Animation Animation

T+hh refers to the forecast’s time interval (hh), in hours, from the hour T of the model’s initial run time. The hour T is indicated, in Universal Time, at the top of each column.
NOTE: Products from 00 and 12 UTC model runs are normally updated by 04:30 and 16:30 UTC, respectively.