By Anders Lorenzen
The production of concrete is one of the highest emitting industrial processes globally and contributes 8% to the world’s CO2 emissions, and the global demand for concrete continues to increase. But fixing the emissions challenge is not easy or straightforward and may create other problems according to a study from the University of California, Davis, which had found that some of the most commonly discussed solutions could increase air pollution and contribute to other health-related damages.
Their study, published in the journal ‘Nature Climate Change’ quantified the costs of climate change impacts and of death and illness from air pollution, through which scientists found that the production of concrete causes yearly damages of $335 billion. They also compared a series of greenhouse gasses (GHG) reduction strategies to work out which would be most likely to reduce both emissions and air pollution in concrete production. They found a host of different methods which together could reduce climate and health damage costs by 4%.
Some of the most effective ways to reduce emissions are to use cleaner-burning fuel in kilns as well as more renewable energy in the concrete manufacturing process and replacing a portion of the cement used in production with materials with a lower carbon footprint. Carbon capture and storage (CCS) technologies could also reduce emissions by 28% but that would come with a significant health impact as it could increase air pollutants unless powered by renewable energy. On a practical note, it is not currently widely implementable.
Frances Moore, Assistant Professor with the UC Davis Department of Environmental Science and Policy and co-author of the report said: “Air pollution and climate change problems are really intertwined when we talk about solutions. This paper takes these two problems and their joint nature seriously. It shows how different solutions have different effects on global climate change and local air pollution, which may matter a lot for policymakers.”
The study underpins that climate action and reducing air pollution is not necessarily mutually complementary. Globally, cement production is responsible for about half of the total climate (32 %) and health (18 %) damages of making concrete. That is followed by aggregate production, which is responsible for 34 % of health damages and 4 % in climate damages. Mixing concrete, or batching, contributes little to climate damages but represents 11 % of health damages.
Therefore the authors of the report argued that if we are to tackle climate change and air pollution at the same time, several technologies and strategies should be looked at.
In terms of reducing emissions, the study recommended using cleaner combusting kiln fuel, increased use of limestone filler or other low-impact mineral additions which will partially reduce cement and using renewable energy. In addition, amine scrubbing and calcium looping, which are forms of carbon capture storage, could reduce climate damage costs over 50 % and 65 %, respectively. They are not yet readily implementable but may become so in the future.
When it comes to reducing air pollution the study recommended that cleaner combusting kiln fuel is shown to have the greatest benefit with a 14 % reduction in health damages – this is four times as large as any other mitigation strategy. In addition, the authors noted that strategies and policies which reduce particulate matter emissions may reduce air pollution more directly.
The world’s major concrete-producing countries are the US, China, Brazil, India and Russia. The study stated that the effectiveness of strategies varies by region but a mixture of them could reduce climate and health damages by 85% and 19 % respectively.
The lead author of the study Sabbie Miller, an Assistant Processor in the UC Davis Department of Civil and Environmental Engineering said: “There is a high emissions burden associated with the production of concrete because there is so much demand for it. We clearly care a great deal about greenhouse gas emissions. But we haven’t paid as much attention to health burdens, which are also driven in large part by this demand,” she said
“As the cement and concrete industries make large efforts to reduce greenhouse gas emissions, it is critical that they remain mindful of the impacts decisions have on other environmental burdens to avoid undesired side effects,” Miller concluded.