Air Quality PM2.5 Data and Forecasts


  • | Premium

    Hey all

    I have been using your PM2.5 air quality data and forecasts to be informed about air quality in Sydney during the bushfires.

    This has worked really well until about last week, when your model did not represent reality at all. For example, on 8 January 2020, air quality in Sydney (Darlinghurst) was really bad and PM2.5 went up to above 100 microgram per cubic metre (with hovering around 50 other times during the day), whereas your map showed PM2.5 to be at around 10 microgram per cubic metre most time during the day. The model also did/does not forecast or show the poor PM2.5 situation in Sydney yesterday (11 January) or today 12 January (just now at 10:45am, your map shows 9 microgram per cubic metre whereas AirRater shows 51 and it is really smoky outside).

    Is there any explanation for this and can your forecast be made more reliable?

    You are the only source I can find to do some forecasting on this, which is really valuable.

    Sascha


  • Moderator Mariners - Seafarers Sailor

    Windy does not create any forecast data but instead only visualises forecast and actual data received from various third party providers.


  • | Premium

    Thanks jmh2002. I understand this, however, the forecast visualisation provided did not reflect what was actually happening and, thus, was not useful. My question is more about the reliability of windy.com's "forecast visualisations". Sascha


  • Moderator Mariners - Seafarers Sailor

    The forecast visualisations are based on the forecast data received. So Windy has no part in the reliability of this.

    If the actual conditions have changed relative to the previous forecast then the visualisation of this data will of course not reflect this.

    PM2.5 is forecast data from https://www.copernicus.eu/en ( https://community.windy.com/topic/7924/cams-signs-partnership-with-weather-application-windy ) and it is updated every 24 hours., It is not actual data and with rapidly changing conditions such as the fires in Australia this may result in some differences..

    For all layers you can check the source of the data by clicking the clock/time/info icon in the bottom right hand corner.

    Please see the following screenshot:

    Windy_ PM2.5 - Google Chrome 2020-01-12 09.28.56.jpg



  • @jmh2002 Hi same problem on the Canary Islands. From the 09.12 to 04.01 , and even today, dust mass forecast doesn't nearly represent the actual situation. Forecasted dust content ppm values are up to 300 times higher than the actual value.
    The problem results in the model calculating correctly dust ingress and dilution in air, but doesn't respect dust trapping by precipitation.
    On regular days, dust mass forecast is fairly accurate though. Those are only the Sahara dust outbreaks that are miscalculated.

    Thank you for your attention


  • Moderator Mariners - Seafarers Sailor

    @jmh2002 said in Air Quality PM2.5 Data and Forecasts:

    Windy does not create any forecast data but instead only visualises forecast and actual data received from various third party providers.

    I am requoting the above to again remind users that Windy has NO control over the forecast or actual data provided. Windy only visualises this data.

    For improvements to the forecasts please feel free to contact the model providers such as https://www.copernicus.eu/en , ECMWF, GFS, etc, and update them with your concerns.

    Although normally forecast anomolies can be explained or understood in many different ways, the simplest of which is that it is a Forecast (ie: an advance prediction) - it is not actual live data.

    Thank you for your understanding.



  • One thing I would love is for air quality to be added to the forecast information for a place. At the moment you can manipulate the map to see forecast air quality everywhere at one point In time, but you cannot see the forecast over time for one place. In Australia we now need to plan our lives around air quality.


  • Moderator Mariners - Seafarers Sailor

    @chrisloader said in Air Quality PM2.5 Data and Forecasts:

    One thing I would love is for air quality to be added to the forecast information for a place. At the moment you can manipulate the map to see forecast air quality everywhere at one point In time, but you cannot see the forecast over time for one place. In Australia we now need to plan our lives around air quality.

    This might be a helpful addition. However also please note that you can see the various air quality forecasts over time for one place by using the time slider in the bottom left hand corner.

    Please see the following screenshots:

    Windy_ PM2.5 - Google Chrome 2020-01-15 08.19.12.jpg

    Windy_ CO concentration - Google Chrome 2020-01-15 08.18.11.jpg



  • Thanks, I am ideally wanting to see the forecast for the next five days at a glance - without having to go forwards and backwards on the slider and piece it together in my head.

    Thinking more generally, there might be other aspects of forecast conditions some people want to see at a glance (eg forecast humidity). Maybe you could have a general option to show standard/customised/all forecast variables, where you choose the forecast variables for the custom option? Or simply add an “all variables” option?

    Love the product by the way! Awesome work.


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