Friday, December 6, 2013

PM2.5 Forecast for Beijing – Saturday, December 7, 2013

We're in for another day of poor air quality on Saturday in Beijing.  We're expecting some ups and downs, but you can generally expect to see conditions at Very Unhealthy or Hazardous for most of the day.  But don't despair:  it looks like we can expect clearing skies at some point on Sunday.

UPDATE – Our prediction with overlay of actual readings:


  1. What model are the predictions based on and how accurate is it?

  2. It's a model I created based on a review of the weather and pollution data for Beijing over the last year or so. As to its accuracy, it's probably best judged by looking back at the last couple of months of posts where you can see how the actual pollution levels look superimposed over the predictions. On the whole, I think it's fair to say that it is a pretty accurate model, particularly so when you consider that it's not intended to catch every possible outcome. Such a model might be more accurate, but it would be less useful on a daily basis. (It's painful to post a prediction that, at a given hour, gives a range from Good/Moderate all the way up to Very Unhealthy or Hazardous, even though there are times when a literal interpretation of the model might leave you with that prediction.) So, sometimes the prediction is wrong because the weather conditions do not match the forecasts used for the model, and other times the prediction is wrong because the change in air quality was what you could consider to be an outlier result for the weather condition.