The public health risks of air pollution: Interview with Kirk Smith

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Smog in Temuco. Photo: Carlos OrtegaSmog in Temuco. Photo: Carlos Ortega


Kirk Smith is the director of the Global Health and Environment Program at the School of Public Health at the University of California at Berkeley. An internationally renowned scientist on global public health, among other things, he has been a lead advisor on climate and health issues for the Intergovernmental Panel on Climate Change and is a member of the executive committee for the World Health Organization Air Quality Guidelines.
On his website, Smith describes the main focus of his ongoing research as the intersection between “environmental quality, health, resource use, development, and policy in developing countries, with a focus on the health effects of air pollution exposure in developing countries, particularly in women and children from household air pollution due to solid fuel use.” In recent weeks, with some cities in southern Chile, such as Temuco or Coyhaique,  registering the highest levels of air pollution they have ever seen, with serious threats to public health such as respiratory diseases and other long term chronic illnesses, Patagon Journal’s Clara Ribera interviewed Smith about the air pollution risks for the region. Excerpts:
The city of Coyhaique has registered as high as 910 ug/m3 –the measurement that quantifies the amount of harmful particles suspended in the air– at time during this autumn. How dangerous is that?
Although that is not the average, it is still very high. It is well above any emergency level that anybody has established and it is not acceptable for health. It is only a single measurement, in a single place, and it doesn’t really tell you what is going on, but it is likely to be fairly representative of the situation there in the winter. It is equal to the worse cities in the world: New Delhi and Beijing. We can speculate all we want, but this number is unacceptable.
How can this affect the population living there?
First, we need to make clear the difference between short and long-term exposure. Healthy people can stand short-term high levels without any noticeable problem. For example, if you go camping and you have a campfire you get very high levels of smoke for a very short period as you are sitting around the campfire. For people with chronic respiratory disease, asthma or other medical conditions it is not advisable, but for the rest of us, it is not that much of a hazard. On the other hand, over the long term –a few years– levels around 20 or 30 ug/m3 can end up causing heart disease, lung cancer, strokes. It is particularly important to protect older people, or those who have respiratory diseases, babies, or people with asthma. 
If you have respiratory problems, what can it lead to?
The diseases that are more closely associated with air pollution are the same set of diseases related to smoking. Smoking is basically sticking burning biomass in your mouth, and what you have is burning biomass in people’s stoves. It is not as bad as having it in your mouth but it causes the same kind of diseases, with a lower risk. Basically, heart disease, chronic lung disease, bronchitis, lung cancer, pneumonia in young children, which is the chief cause of death of young children around the world, or even, there is some evidence that air pollution triggers tuberculosis. We’ve published several studies in Asia showing that wood smoke is related to tuberculosis, but it takes several studies in different places before the health community is willing to accept anything. They are conservative, of course. The ones that are accepted are the ones from smoking: heart disease, stroke, chronic obstructive coronary disease, COPD, lung cancer and pneumonia. We have some evidence about other things, too, but those are the main ones.
Kirk Smith, Director of the Global Health and Environment Program School of Public Health University of California, Berkeley. Kirk Smith, Director of the Global Health and Environment Program School of Public Health University of California, Berkeley.
How are climate change and air pollution related?
It is clear that air pollution can contribute to climate change. But I would say that climate change might actually help the situation in Chile because winters will be warmer, so people would burn less wood. On the other hand, the smoke coming from burning wood has other greenhouse gases besides the PM. And I am sure that in Chile, it has an impact on climate and of course it has an impact on the glaciers, for example.
Finland is a developed country and still uses wood.
It’s because they have access. The places in the world that have wood nearby and need heating, use it. Nepal is a poor country that uses wood for heating. Chile is a middle-income country that uses wood for heating. Canada is a rich country that uses wood for heating. And in all of them it is because they have availability. 
So, there is no link between income and using wood as a means of warming houses?
In general, people who tend to use wood fuels are poor people everywhere in the world. In some cases they have no choice, and others just find it cheaper. We need to propose interventions, such as laws. However, we need to take into account that they could negatively affect poor people more than rich ones. If we are going to require expensive clean wood stoves, for example, we would have to provide some sort of subsidies or low interest loans. The problem in Chile is that the result from the wood stoves is outdoor air pollution, so this affects everyone. And that really argues for more government action rather than putting all the responsibility on individuals. 
What do you propose as an alternative, especially in Chile?
Wood pellets are a lot cleaner than just pieces of wood, so that’s an intermediate category between requiring new wood stoves and burning any kind of wood. Big pieces of wood are very difficult to burn cleanly, no matter what you do. Yet the cleanest stove is never clean enough, according to air pollution standards. If you are on a mountain top all by yourself, the smoke goes down with the wind and nobody gets affected but most of us don’t live by ourselves anymore. A lot of things that we could do when we lived by ourselves, we can’t anymore with the population densities that we have. Now, we also understand the health effects wood smoke provokes, while 60 years ago we didn’t. Sixty years ago we didn’t know about cigarettes, and now we do. Things change. People can’t just do what they used to do without understanding that there are consequences. Health consequences in this case.
In Chile, they are trying to promote certified wood.
That would certainly help, but of course it is hard to regulate. There are pickup trucks coming and selling wood, in the neighborhoods. You can’t have the police running around controlling what people burn. It is not an easy problem, but I applaud Chile for trying to do something about it. With the use of certified wood we would see a difference, a factor of one to two, when what you would really like to see is a difference of ten. But yes, it would help. The more we can regularize the fuel, the better performance in terms of efficiency and air pollution we will get. 
Would pellets work as a short-term solution, then?
I have seen designs of pellets and stoves in Europe and China that are really clean, or at least clean enough. Not as clean as gas, but then the country needs a pellet industry. You can’t have the guys just going to the forest cutting wood and going into town with the pickup truck anymore. With the use of pellets, an automatic feeding system could also work. It would be less work, and not so dirty in the house. You basically have a bin of pellets feeding the stove as needed. Most Chileans have electricity, or it could be done by gravity. We could set up some industries, create jobs, and people could still use wood, but wood pieces. 
What do you think of the biomass district system?
That can be very clean because you can afford the air pollution control system but then you have to pipe the heat. They do that in Austria. They have heating plants, and pipe the water into towns. But it is not cheap. 

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