Last week, the World Health Organization (WHO) named Coyhaique, the capital of Chile’s Aysen region, the most polluted city in the Americas.

 

The city, with a population of just over 60,000 people, appears in the list with an annual concentration of fine particulate matter (PM2,5) of 64 ug/m3 (micrograms per cubic meter).

 

The report reminds us of the problem Chile has faced for years in its central and southern cities. Osorno, Valdivia, Temuco, Rancagua and Santiago also appear in the same report as having higher values than the 20ug/m3 maximum recommended by the international organization. “Having an open fire in your kitchen is like burning 400 cigarettes an hour,” says Dr Kirk Smith, a professor of global environmental health from the University of California at Berkeley.

 

In addition to emissions produced by transport, industry, and above all the use of firewood for heat, southern Chile is dealing with another problem: a lack of rain. The rainfall shortage in Coyhaique has increased by as much as 75% compared to the same period last year.

 

For several years, the most used indicator to measure the amount of pollution in the environment was PM10. Some years ago, WHO recommended the use of PM2,5 instead. What are these indicators?

 

PM is the abbreviation for particulate matter, which can be found in cities’ atmospheres in solid or liquid form. They can be divided into two groups based on size: particulate matter that has a diameter equal or smaller than 10 micrometers (a thousandth part of a millimeter), and particulate matter that has a diameter equal or smaller than 2,5 micrometers. This characteristic defines the intensity of its impact.

 

The reason the World Health Organization prefers to use PM2,5 as a measure of environmental pollution is because these particles are more harmful to the human body than PM10. Still, the latter is often used because in countries such as India and China its the only indicator collected at the time.

 

Along with other pollutants such as ozone, sulphur dioxide and nitrogen dioxide, particulate matter is very harmful to our health. Nowadays, it is associated with several cardio-respiratory conditions like bronchitis and asthma.

 

According to a 2011 report from the Chilean government, 4,000 people die every year from chronic exposure to PM2,5, a figure that ascends to 7 million in global terms, according to WHO. It is calculated that around 10 million Chileans are exposed to MP2,5 values higher than recommended.

 

Other related effects are poor visibility, material damage –it can affect physical and chemical features in construction materials, for example–, and harm to aquatic ecosystems, plants, and forests.

 

Many homes, especially in southern Chile, are heated with wood stoves, one of the main sources of polluting gases in the country. According to a December 2015 report by Chile’s energy ministry, the energy consumption for heating between the regions of O'Higgins and Aysen comes 81% from the burning of firewood.

 

Although the government has plans to promote more efficient heating systems and improved insulation in houses, most homes in Chile have a long way to go to become efficient.

 

A first step for the short-term ought to be the use of certified firewood. Air pollution does not occur solely by the simple act of burning wood, but by bad combustion of humid or wet wood. If dry wood is used, a large quantity of contaminants can be reduced. In addition, dry wood lasts longer and heats up more.

 

Another alternative is FiltroVivo. Recently launched in Chile, this entrepreneurial initiative has created a vegetative wall that works as a bio-filter and is able to retain and recycle the particular matter generated as a result of wood stove combustion. It basically converts the smoke into clean air. The mechanism has an automatic temperature sensor, and when it detects a temperature higher than 60 degrees, an extractor fan directs the smoke to the green wall, which absorbs the polluting particles and transforms them into 90% cleaner air. The particles are biodegraded by the wall microorganisms and turned into vegetable fertilizer.

 

The good news for Coyhaique, a pilot project is in the works, planned for construction early next year, a biomass district heating system similar to that of Santiago’s El Condor condominiums will be installed in part of the city. The method consists of a pipeline connecting a district’s buildings through which hot water is distributed for heating. The energy is produced with biomass from a central boiler that supplies the entire district. The biomass consists of affordable fuels such as pellets, splinters, and wood chips.

 

It’s a long road to minimizing air pollution, and at present Chile is lagging behind and putting at risk its citizen’s health and the environment.