Qualité de l’air à Osorno

What is the current level of air pollution in Osorno City?

Osorno is a city and commune in southern Chile and the capital of Osorno Province in the Los Lagos Region. It is located some 945 kilometres south of the capital, Santiago. It is a gateway for land access to the far south regions of Aysén and Magallanes, which would otherwise be accessible only by sea from the rest of the country. According to a census conducted in 2002, Osorno had an estimated population of 145,475 people.

The level of air pollution in August 2021 was classified as being “Moderate” with a US AQI reading of 55. This United States Air Quality Index number is calculated using the levels of six of the most commonly occurring air pollutants, such as nitrogen dioxide, sulphur dioxide, ozone, carbon monoxide and both sizes of particulate matter, which are PM2.5 and PM10. It can then be used as the metric when comparing air quality in other cities around the world. If data is unavailable for all 6 pollutants, a figure can still be calculated by using what figures there are.

The recorded figures for Osorno were that of PM2.5 which was 14 µg/m³ and PM10 which was 15 µg/m³. This level is just over one and a half times higher than the recommended level of 10 µg/m³ which is the suggested maximum figure by the World Health Organisation (WHO), although no amount of air pollution is considered to be safe.

With the level of air pollution of this magnitude, the suggested advice would be to stay indoors and close windows and doors to prevent the ingress of more polluted air. Those who are sensitive to poor air quality should avoid undue outdoor contact. It would be beneficial to use an air purifier if one is available, but make sure the air intake is set for recirculation so that it is not sucking more dirty air in from outside. If venturing outside is unavoidable, then a good quality particle filtering mask should be worn at all times. The table that is published at the top of this page should help with that decision or download the AirVisual app for constant updates as to the state of the air in real-time.

Does the level of pollution stay the same throughout the year in Osorno?

Air quality can vary considerably, depending on the meteorological conditions at any given time. Looking back at the published figures for 2020 by IQAir.com, it can easily be seen that the month with the worst air quality in Osorno was July with a reading of 39.6 µg/m³. With figures such as this, the air quality is classed as being “Unhealthy for sensitive groups” with readings between 35.5 and 55.4 µg/m³ to quality as such. April, May and June and August, September and October were the next worse months, returning figures between 12.1 and 35.4 µg/m³ which would be classed as “Moderate” air quality. For the remaining four months of the year, Osorno achieved figures which were less than the target figure as suggested by the World Health Organisation (WHO) of 10 µg/m³. The cleanest month being January with a figure of just 5.0 µg/m³.

Records pertaining to air quality were first kept in 2017 when the annual average was seen to be 30.8 µg/m³. An increase was seen for the following year of 38.2 µg/m³. Then a noticeable improvement in 2019 when the figure was 32.8 µg/m³. The 2020 figure of 19.2 µg/m³ coincided with the COVID-19 pandemic when many vehicles were no longer in daily use in an attempt to stop the spread of the virus. Many factories and non-essential production units were also required to close which removed their emissions from the atmosphere and therefore, most cities revealed very good figures for air quality.

What is the source of air pollution in Osorno?

In 2013 the World Health Organisation classified outdoor air pollution as being carcinogenic to humans. A dense layer of smoke, which at times is confused with fog, but which corresponds to the suspended soot emanating from heaters and wood-burning fireplaces, made the air unbreathable in the urban conurbation Osorno, where the content of particulate matter in the air exceeded twice in a row the maximum standard considered dangerous for human health. The origin of this pollution in Osorno, corresponds 85 per cent to the combustion of wood in heaters, fireplaces and wood stoves, used in some 65,000 homes.

Unlike the industrialized and populous cities such as Beijing and New Delhi, Osorno is home to only 145,475 people and pollution is not the result of economic activity, but of a lack of resources, which forces the vast majority of its inhabitants to depend on of wood stoves to cope with low winter temperatures.

Can anything be done to reduce air pollution in Osorno?

So far, only two measures of the local decontamination plan have been anticipated: the delivery of subsidies for thermal insulation of houses, and a municipal ordinance to prevent the sale of green firewood, which is the most polluting. The entry into force of the rule that made it forbidden to commercialize firewood that exceeds 25 per cent humidity, has no visible control as yet.

Around 88 per cent of the stoves that are used in Osorno are used with firewood, despite the fact that the Chilean Government launched an atmospheric decontamination plan that contemplates the change of these devices for pellet stoves or paraffin. However, it is an initiative aimed at the vulnerable population and the elderly, which does not include the bulk of the population.

What are the detrimental effects of air pollution in Osorno on our health?

According to the WHO, Chile is one of the countries with the highest environmental pollution in Latin America. In the south of the country, the combustion that is generated by the excessive use of firewood for heating homes is part of 95 per cent of air pollution. Low temperatures, geographical conditions that enclose the city and poor ventilation favour the increase of fine particulate matter in the air.

Regarding particulate material, coarse particles, whose size is between 2.5 and 10 microns, come from the suspension of dust, earth or other materials from the road, agriculture, mining, wind storms or volcanoes. Meanwhile, fine particles of less than 2.5 microns come from emissions from combustion processes, such as gasoline, diesel, firewood combustion and industrial processes. The latter are the most dangerous for people's health, since they are capable of entering the respiratory system and from there into the bloodstream, and can also affect the cardiovascular system.