Smog is a combination of smoke and fog. So some might think that a solution might be to address the fog, rather than the smoke. But the fog is just making visible the pollution that's around all the time. There will be many incidents of toxic levels of pollution, even when there's no smog. So addressing the smoke is fundamental.
Smoke comes about from burning complex hydrocarbons. In the case of Harbin, and in many similar cases around the world, that's coming from burning coal, and from burning stubble.
There are two ways to drastically reduce particulate emissions: stop burning the things that release particulates, or trap the particulates straight after combustion. The latter is more expensive, and only addresses part of the problem: particulates are just one of the pollutants: SOx, NOx, CO and CO2 are associated pollutants also released by combustion that will not be caught by a particulate trap.
Stubble-burning used to be common in lots of the world, but has been stopped in many places because of the pollution impact. Ploughing stubble back in prevents the loss of trace nutrients, and can reduce soil erosion. See this pdf report from the US DoE for more about this.. Changing this behaviour will need education for the farmers - there is a common belief that burning kills all pathogens (it doesn't). The Saskatchewan government proposes several alternatives to burning, including chaff spreading, chaff collection, post-harvesting harrowing, and turning surplus straw into an economically useful commodity, selling it as forage.
Coal-burning is also in decline in most of the world, as a nineteenth-century relic that has long past its useful life. It's a major source of greenhouse gases, as well as of particulate pollution. The good news for Harbin, is that because a lot of its heating is provided through the municipal heating system, it's relatively easy to clean up the heating supply for the city. Much easier than it would be for a city such as London, in Europe, where almost of the heating systems are in the individual buildings of the users of the heat, so cleaning up London's heating would mean gaining access to millions of buildings to replace millions of boilers. There are several options for Harbin, and the right answer will be a combination of these:
- a very large thermal store (a gigantic hot-water tank)
- electric ground-source heat-pumps with a large area of exposed ground to collect from: note that this is effectively harvesting solar power stored as ground heat, so the rate of extraction of heat mustn't exceed the average annual rate of insolation onto the ground.
- electric resistance heating for meeting peak demands, and for helping to provide balancing services to the electricity grid.
- solar thermal collectors
- possibly biomass boilers with particulate traps
- geothermal power may be an option, depending on the local geology.
Coal is a cheap fuel, because the buyer of the coal doesn't have to pay for the pollution caused. Burning stubble is a cheap way to clear fields after harvest. One way to tackle this is to change relative prices, so that a cleaner alternative is cheaper: this has had very mixed results around the world. It can be done through a combination of subsidising cleaner options (less public objections, but then energy-efficiency measures no long look as attractive) and through the polluter-pays principle, whereby a tax is added to the polluting process, to internalise the damage costs.
Prices are not the only way to change behaviour. Regulation is another route: enforced regulations to drastically reduce or prevent the destructive choice. This has historically had much higher success in tackling pollution than price mechanisms, but in cultures where belief in the efficiency of markets dominates, it may be more difficult to establish. A change in relative prices can help establish an environment of support for subsequent regulation.
First, you have to identify who the agents of change are: who is it who can change what's happening now. These will often be people with economic and/or political power. Then you have to work out how to motivate them to bring the change about. What do they want, and can you find a way to link the change you are seeking, with the thing they want. Alternatively, what do they want to avoid, and can you find a way to link the status-quo, with the thing they want to avoid?
Harbin does have advantages, and making the most of those advantages could be crucial to success. The municipal power plant makes technology-switch faster and easier. There is money available, including a 10 billion yuan fund to reward efforts to curb air pollution.
And there are national policy initiatives happening right now to curb particulates emission, as part of the Airborne Pollution Prevention and Control Action Plan.
next steps for Harbin
Engage the people. Engage the Party. Engage Academia: this sort of problem will need the input of engineers and social scientists - just the sort of thing that multi-disciplinary university energy departments do. (disclosure - that's what I do)