Some residents of Beijing use smokestacks to predict smog: Smoke drifting gently upwards equals stagnant air where smog will accumulate. Smoke blowing away from the mountains signals fresher winds and clear air ahead.
However, the city government uses more complicated technology for its forecasts, such as the one used to trigger Beijing’s first red alert for smog this week, which resulted in restrictions on factories, cars and other measures focused at keeping the smog in check.
The system considers not just weather patterns that suspend pollutants in the air, but also flows of vehicles and their emissions, and industry emissions – which will vary depending on the day of the week and time of day. The technology includes real-time data from air-monitoring systems, satellite images – and also information that is spread around on social media, said chief meteorologist, Meng Zhang, at IBM Research, China, which works with Beijing’s environmental bureau on the forecasting system.
The technology then predicts and models the impacts of weather on the dispersal and flow of pollutants, and the airborne chemical reactions between pollutant particles and weather, Zhang stated in an interview at an IBM research lab in Beijing. It produces high-definition pollution forecasts 72 hours prior, as well as estimated predictions for 10 days in advance, he added.
Beijing’s present system of smog alerts triggers a scaled answer with general restrictions for the whole city for four levels of predicted pollution.
Zhang stated that the system can become more granular, permitting authorities to identify just the right restrictions – which factories should suspend operations and which should not – at the correct time to achieve the desired effect.
Without this understanding the government does this in a very basic way. They close everything around Beijing, just like how they did for the 2008 Olympics, when factories were shut down for a month. However, for the 2022 Winter Olympics they can do the same thing in a smarter way, so they are aware of what is the best window, and the best area, to minimize economic impact.