Better forecasting to head off acute pollution events in Asia
Air quality in South East Asia is a major concern as the region further develops. European and Chinese scientists teamed up to develop space and ground-based tools and methods to monitor, model and forecast regional air quality and a growing list of emission types. Authorities can use the tools to plan for or prevent acute air-quality incidents, potentially saving thousands of lives.
© Tom Wang, #95595165, 2018. source: stock.adobe.com
Air-quality forecasts are notoriously tricky to get right. They need to continually monitor pollution levels, which literally change like the wind, and with variations in temperature and cloud cover. Accuracy matters because severe pollution events can be the source of major health problems and even deaths, especially in regions where increasing industrial development and urbanisation go hand in hand.
This is where the EU-backed PANDA, together with sister project MarcoPolo, entered the picture. The tools they developed combine EU satellite observations with Asian ground air-quality monitoring stations collecting data from traffic, industry and agriculture. The team can trace and predict daily air pollution events over an expanding area of South East Asia.
We developed more accurate and comprehensive forecasting tools, which means authorities are in a much better position to anticipate and deal with the pollution at source, says Guy Brasseur of the Max-Planck Institute in Germany, which leads the PANDA initiative. Actions could include restricting vehicles in hot spots or from entering city centres, rotation schemes to curb industrial emissions and other end-of-pipe measures to cut the amount of particulates like coal or ammonia and improve air quality during peak or dangerous periods.
The impact of the work is not trivial. The World Health Organization estimates that up to 7 million people die prematurely because of air pollution annually. In China alone, around 1 million deaths are attributed to poor outdoor air quality. But PANDAs tools can now predict whether tomorrows air conditions in a city or targeted area will be bad for people with specific conditions, such as asthma or heart disease, or even that visibility will be so low that cycling is not recommended, notes the team.
Right tool for the job
Aware of the need not only to deliver robust scientific results, but also to make them easy to use, PANDAs toolbox is arranged under six clear headings: Air-quality forecasts, Model results, Model evaluations, Observations, Emissions, and Tutorials. The tools are offered on a public platform created through a joint effort between Panda and MarcoPolo and they provide daily forecasts of air pollution for 37 Chinese cities.
To our knowledge, this is one of the most ambitious air-quality monitoring and assessment activities in the Asian region that is freely available to environment managers, local, regional and global authorities, and for wide use by academia or any interested party, says Brasseur. The multi-model, ensemble-based forecasting is a particular achievement in what has been a fragmented approach in the region until now, he believes.
Continual evaluation of the system is key to ensuring forecast accuracy, and for building a longer time series of models/observations for both meteorological and climate research, boosting spatial, anthropological and historical understanding of atmospheric pollution in South East Asia.
Many hands make light work
Well-planned actions and close cooperation between PANDAs 14 European and Chinese research institutions have been critical success factors in the project, or what Brasseur has previously called its essence, creating a lasting collaboration and value proposition to European research and innovation in this important field.
Measures to improve air quality taken in key Chinese urban regions have led to clear improvements in air quality. The forecasts and scenarios provided a solid scientific basis to help policy-makers control emissions, according to Xuemei Wang of Jinan University who is a PANDA principal investigator in China. The Pearl River Delta region, which is one of the largest city clusters in China has been meeting the Chinese air quality standard since 2015. Air quality in the Yangze River region and Beijing-Tianjing-Hebei areas has also distinctly improved, he confirms.
The teams work has attracted the attention of the wider scientific community, which is eager to be part of the initiative, helping to build on the range of pollutants under scrutiny. New models are being added to the so-called Ensemble already covered in PANDAs toolbox. These boost the available inventory of greenhouse gas data and respective projections by using top-down approaches in combination with a bottom up one.
Emission inventories can be developed by adding all individual sources identified and reported at the surface; this is what we mean by the bottom-up approach, explains Brasseur. Several of these inventories including those produced by our Chinese partners are available, but there are gaps in our knowledge on the emissions that need to be filled by satellite observations of atmospheric concentrations of certain chemicals near the surface. This approach combined with models constitutes the top-down approach.
Several contributors such as the Finnish Meteorological Institute have joined the effort, adding daily readings for gasses like ozone, carbon dioxide, and more across China, India, Japan, and neighbouring South East Asian countries. As, too, has the Shanghai Centre for Urban Environmental Meteorology whose WRF-Chem model has a 6-km spatial resolution and covers the eastern part of China with daily forecasts. And the latest addition to Ensemble is the WRF-CMAQ model operated by the International Institute for Earth System Science at Nanjing University.
The inventory of gasses, coverage and accuracy of the forecasting is expected to keep growing as word of PANDAs tools spreads to other regions and cities in the world also dealing with concurrent industrial, urban and air-quality pressures.