Page - 11 - in options, Volume summer 2021

The study includes a scenario where a 1.5°C world also pursues aggressive clean-air policies. This means applying the best pollution abatement measures available today. For example, all power plants use desulfurization technology, catalysts to remove nitrogen oxides, and electrostatic precipitators to filter out fine particles. The impact is huge. According to the GAINS model projections, in 2050 this “maximum feasible reduction” strategy reduces premature deaths across Asia by nearly 45% compared with the baseline. Another IIASA study gives an idea of what will be needed to bring clean air to a majority of the world population. The World Health Organization air quality guideline is that annual mean PM2.5 levels should be no higher than 10 micrograms per cubic meter. In 2015, only about 18% of us were breathing air that conformed to this guideline. The research showed that a clean-air scenario could raise that number to 56% in 2040. This, however, requires policies that deal with all polluting sectors, including energy, agriculture, and waste management. “To get to these really low levels, you need to use all the options available,” says Kiesewetter. Climate and clean-air policies however need to be carefully coordinated, as some measures that cut greenhouse gases actually increase pollution. Biomass burning, for example, can be a strong source of PM2.5. In Europe, this is now being recognized. The EU’s Second Clean Air Outlook, which contains major contributions from IIASA, includes research into the co-benefits of climate and pollution policies to inform the upcoming zero-pollution action plan. “More needs to be done to provide clean air for all,” concludes IIASA Pollution Management Research Group Leader, Zbigniew Klimont. “Any day with polluted air is a lost day causing suffering that can be avoided.” By Stephen Battersby Gregor Kiesewetter kiesewet@iiasa.ac.at Zbigniew Klimont klimont@iiasa.ac.at Pallav Purohit purohit@iiasa.ac.at Peter Rafaj rafaj@iiasa.ac.at Megacity air Big cities face some of the world’s worst air pollution. A 2020 World Bank report “Clearing the Air – a Tale of Three Cities” examined responses in Beijing, Delhi, and Mexico City. Input from IIASA research included a long-term collaboration with the World Bank to tailor the GAINS model to local conditions in highly polluted regions. The report recommends a three-pronged approach through information, incentives, and institutions. Accessible information about pollution can galvanize public support, as it did in Mexico City with an analysis of air pollution and children’s health. “Countries need a strong mechanism to incentivize local air-quality programs and institutions must involve a range of stakeholders addressing all relevant pollution sources, as air pollution does not care about administrative boundaries,” notes Pallav Purohit, a researcher with the Pollution Management research group. We tend to think of city pollution as a homegrown problem, the noxious consequence of diesel engines and heavy industry. IIASA and the Indian National Environmental Engineering Research Institute however found that 60% of PM2.5 in Delhi was actually coming from outside the city, for example, from crop burning. Clean-air policy therefore needs to transcend jurisdictions – as with the Jing-Jin-Ji Regional Air Quality Prevention and Control Coordination Group in the Beijing area, the Megalopolis Environmental Commission in Mexico, and the newly established Commission for Air Quality Management for the area around Delhi. Further information: www.iiasa.ac.at/ece/pm pure.iiasa.ac.at/17033 pure.iiasa.ac.at/17043 pure.iiasa.ac.at/16750 pure.iiasa.ac.at/14552 www.iiasa.ac.at 11