From the Paris Climate Negotiations
By now everyone who follows environmental news or looks at the front page of major newspapers knows that in the last two weeks Beijing has suffered through not one but two of these major multi-day air pollution events that have come to be known as air-pocalypses. Having such a spate of bad air in its capital city just as China was advocating for its green agenda in Paris was undoubtedly somewhat embarrassing to Chinese negotiators, but what does it mean beyond that? We’ve seen commentary suggesting everything from “how can we believe Chinese commitments,” to “this will increase Chinese efforts and make the issue more visible to Chinese.” But what really do conventional air pollution and greenhouse gave emissions have to do with one another? Let’s dig in a bit.
Why was the air suddenly so bad?
Firstly, and perhaps counterintuitively to those who don’t study air pollution chemistry, it is NOT because the amount of emissions either from cars, from factories or from households increased. I discussed the situation with Chinese Academy of Sciences air pollution and climate change modeler Dr. Hong Liao, who is here at the Paris meeting to discuss some of her findings. Dr. Hong said that as with previous air pollution events the underlying amount of what are known as primary pollutants – the stuff that comes out of chimneys and exhaust pipes – didn’t change, but that weather conditions contributed to an accumulation of secondary air pollution – the type of pollution that is produced by chemical reactions of primary pollutants in the air and that actually causes most of the health impacts. Primary among these in China is PM 2.5. There are four major factors that lead to the build-up:
Wind – or the lack thereof. As anyone who has spent time in Beijing knows, when the wind blows in from the north the city is pretty clear, but when the wind dies down, pollution tends to accumulate. This is a particular problem in Beijing, because it has mountains on two sides and is prone to the types of temperature inversions that used to lead to horrendous bad air days in cities like Los Angeles, as well.
Low boundary layer – this is the layer above the ground level atmosphere and it is lower in winter, Dr. Hong said, trapping pollution below it.
Temperature is a complicated one – warmer weather produces more sulfates, one type of PM 2.5, while colder temperatures produce more nitrates, another type of PM 2.5. The net result is that according to Greenpeace’s Lauri Myllyvirta–who is the preeminent data cruncher among China environmentalists–on average, bad air days are associated with warmer temperatures.
Humidity. Dr. Hong said more humidity is definitely associated with these high pollution events – that is the origin of the word “smog”. Air pollution and water vapor mix together.
Thus, the underlying emissions level didn’t change, but air quality got much worse.
But wait a minute, aren’t the Chinese trying to reduce air pollution?
Yes, they are, but they began in earnest about 10 years ago, and they estimate they need at least another fifteen. In the five years from 2006 through the end of 2010, total sulfur dioxide fell by a little more than 15%, and since 2011 it has fallen almost 13% more. However, China needs to continue to reduce sulfur emissions, and to control others, as well. In reporting progress in pollution abatement for the 12th Five Year Plan, Environment Minister Chen Jining was not congratulatory, but said that pollution needed to be reduced another 30-50%. This includes not just sulfur dioxide, but nitrogen oxides, volatile organic compounds and other pollutants that go into producing the small particulates called PM 2.5 that are the heart of the China air pollution problem. A number of these regulations are only being phased in now. NOx controls began in July 2014, and VOC control is still in progress.
So basically at this point a city like Beijing has decent air quality only when the weather is in its favor, which obviously isn’t all the time, although it is some of the time. Other cities in China with less wind have more consistently poor air quality, although if they don’t suffer from temperature inversions, they also don’t necessarily have these extremely poor air quality events.
Obviously, air quality is an everyday need, so the Chinese need to do more, and they are in the process of doing more. They have ambitious goals to reduce pollution in the Beijing, Shanghai and Guangzhou areas by 2017. These are challenging – not all experts think they can meet them, but what we’ve seen in the past decade is the Ministry continues to push new, tougher regulations and to increase its enforcement tools. We can expect to see improvements, but we can also expect to see more bad air days until levels are reduced considerably more than they have been to date.
But didn’t the Chinese declare a Red Alert and shut down factories?
Yes, they did, and according to the Ministry of Environment they reduced primary air pollution, the stuff actually being emitted by factories, by 30%. As of Thursday, air quality had considerably improved, but on Wednesday, despite the shutdowns Tuesday, air quality was still quite poor. Dr. Hong pointed out this is because the poor air quality isn’t really about the new air pollution entering the system, but the length of time it sits there. It is quite possible that without the restrictions air quality would have been even worse. To prevent these cases, the government would have to predict these poor air events and shut down factories before they even start. This could prove challenging. The more realistic and effective option is to control the pollution every day. This is what they are working toward, but it will take time.
So how does this affect climate change?
Local air pollution and climate gases, especially the largest of the climate gases, CO2, are distinct. While there are some climate gases that are also air pollutants, on balance Dr. Hong said that in China, air pollution has a slight cooling effect. This is because this air pollution is mainly particulates that reflect the sun’s light. If you think about this, this makes sense – the main picture you are seeing of Beijing is rather dim – not a lot of sunlight getting through. So when people in Beijing look at pollution, they are not seeing global warming – they are seeing pollution.
Moreover, cleaning up that pollution generally uses some energy, since what is needed is additional equipment on power plants and cars, and additional chemical processes at oil refineries, to remove the impurities from the fuels and the exhaust. Running this equipment uses additional energy – for sulfur removal at a power plant, for example, it adds 5% to the amount of energy used.
While the Chinese are targeting a gradual reduction in greenhouse gases, they need drastic reductions in these pollutants. Thus, they really do need this pollution abatement equipment to control air pollution, even though it does add to energy use. And by the way, these are all standard procedures in the US and other developed countries. We have scrubbers and other pollution abatement on our power plants and use extra energy to eliminate pollutants from our gasoline.
Reducing coal use helps with both air pollution and climate change
But there is another way in which reducing air pollution and climate gases go hand-in-hand, and that is by reducing dependence on fossil fuels. The Chinese now have committed to capping coal, the most greenhouse gas intensive fuel and also the fuel that causes the most air pollution. Coal use actually declined last year, so they are starting to make progress on this front.
Reducing air pollution is expensive, and the ways that they are addressing climate change – increasing energy efficiency and replacing some energy production with renewable and other non-fossil energy sources – also help to reduce the costs of air pollution abatement. If you are going to put all this equipment on a power plant, you want to do it on the most efficient plant possible. And sources like solar, wind and nuclear power do not produce these local air pollutants. In addition, developing public transportation and the rail network help as much with air pollution as they do in reducing climate gases.
So does air pollution in China help focus attention on climate change?
That’s a hard question. Most Chinese today seem more concerned with air pollution than with climate change, but even though they don’t rank climate change as a major problem, according to the latest Pew poll they are highly supportive of a global agreement to limit climate gases. Moreover, the Chinese government may be more concerned about climate change than is the public. For one thing, they see huge advantages to increasing energy efficiency and diversifying their fuel sources away from such a heavy reliance on coal. They also have been increasingly concerned about the impacts of climate change on China. Dr. Hong and her colleagues briefed the international community this evening, and they said China has already experienced 1.52 degrees Celsius of warming in the last century. They are concerned about impacts on rainfall and agriculture and extreme weather events, both droughts and floods.
Moreover, we need to remember that even though we in the United States no longer look out the window and see air pollution, we are still major contributors to global warming. Our per capita emissions are still three times as high as those of the Chinese and we are the second largest total emitter.
Solving air pollution in China is obviously necessary for the health of the Chinese people. It can be combined with policies that also help reduce global warming, in particular energy efficiency and the use of non-fossil fuels, which over time will have a significant effect on air pollution. But it will also present challenges, because it does take energy to run pollution abatement equipment, and because when local air pollution in Asia is solved, it will actually contribute to the world’s warming. So to address global warming, steps will be needed beyond those necessary to deal with air pollution. That should only make us realize how important it is that we have a successful outcome in Paris that sets the whole world on the course to reduce greenhouse gases.
Deborah Seligsohn is a researcher in environmental governance at the University of California, San Diego.