Qualité de l’air à Graz

What is the air quality index of Graz?

Graz is the capital city of the Austrian state of Styria and second-largest city in Austria after Vienna. In 2019 it had an estimated population of 328,276 people.

At the beginning of 2021, Graz was enjoying a period of “Good” quality air with a US AQI reading of 30. This classification is within the guidelines of the World Health Organisation (WHO). The levels of the recorded pollutants were as follows: PM2.5 - 9.5 µg/m³, PM10 - 11.5 µg/m³, nitrogen dioxide (NO₂) - 45 µg/m³ and sulphur dioxide (SO₂) - 15 µg/m³.

With levels such as these, doors and windows can be opened to let the fresh air in and all types of outdoor exercise can be enjoyed without fear.

What is the main source of air pollution in Graz?

The "City of Dust" or also called "Fine Dust Capital” are affectionate names for Graz because it has a bad reputation for its air quality. The air quality values have improved in recent years, but this has little to do with the measures taken.

Traffic noise, stuffy air and fine dust that is deposited on the outside surfaces are disruptive factors that the residents have to struggle with on a daily basis. But the air quality measurements in Graz show that fine dust pollution is also too high in the districts of Gries, Lend and Eggenberg. The city of Graz, with the Don Bosco, Tiergartenweg and Petersgasse measuring stations, has been at the top of the Austrian air pollution ranking for many years.

At the measuring point Don Bosco, the limit of 50 µg/m³ fine dust PM10 was measured on 54 days in 2017. In 2018 there were 39 exceedances and in 2019, the limit was exceeded 15 times again. A spokesman from the Department for Air Quality Control of the City of Graz ascribes this drastic decrease in the number of violation days mainly to favourable weather conditions: “From one year to the next one cannot achieve such a reduction only through the measures that have been taken in Graz. Dust is sensitive to wind and weather, so the decrease in the number of days exceeded is mainly due to the weather which unfortunately is uncontrollable.

Why is air pollution so poor in Graz?

There are several reasons why the air quality in Graz is so bad. On the one hand, traffic, heating and industry are causing increased air pollution. On the other hand, Graz is geographically located in a basin. This means poor ventilation, especially in the colder months. If the upper air layers are warmer than those close to the ground, there is no vertical air exchange. The dust that is produced in Graz cannot be removed in this way.

That leads to the accumulation of pollution. This phenomenon is known as a temperature inversion.

According to the city ranking, the air in Berlin is the purest at 84 per cent, followed by Copenhagen and Stockholm with 82 per cent each. Vienna shares third place with Zurich; the cities each achieved 80 per cent in the rating. Graz is in the middle with 64 per cent. In Milan, it was 44 per cent and Rome 38 per cent, according to the city ranking, the air is particularly bad.

What can be done to improve the air quality in Graz?

The state of Styria set up a mobile measuring station at Griesplatz in February 2019. The values collected there are comparable to those measured at the Don Bosco measuring point. Due to the Corona crisis, however, it is difficult to put these measurements on the right scale because the air quality values have changed radically. The aim of the measurements at Griesplatz is to identify hot spots for pollution from traffic in Graz.

In addition to the mobile measuring station, the Graz 2020 mobility concept was launched. In terms of transport policy, the focus is on so-called soft mobility. This term includes cycling, walking and the use of public transport. The motorised individual traffic of commuters is to be reduced. A City Councillor said in an interview: “We have to think about transport policy beyond our city limits. If we could get the problem with inbound and outbound commuters under control, we would not only have better air quality, but also more free parking space for our residents.

It is very important to strengthen soft mobility. According to the 2018 mobility survey, 19 per cent of all trips taken by Graz residents were by bicycle. The proportions of those who walked and those who used public transport were also between 19 and 20 per cent. “We in Graz do this mobility survey most carefully because we are not changing the survey system. We do the survey every three years. When it comes to cycling, we expect an increase in the next survey.

What are the effects of breathing Graz’s poor quality air?

In the European Union, half a million premature deaths can be attributed to air pollution every year, and the climate coalition estimates the economic damage caused by air pollution for the year 2000 to be at least 277 billion euros.

There are numerous air pollutants that affect health in different ways. Some cause acute illnesses, others lead to chronic complaints. There are also substances that have both acute and chronic effects. That depends on the various properties of the pollutants, the strength of their concentrations, the duration of their exposure and the sensitivity of the individual. It also can depend on the general state of health of the individual.

The main potential effects of air pollutants on human health are that the self-cleaning defence system becomes damaged which can lead to changes in mucus production, paralysis or destruction of the cilia: acute or chronic cough. Irritation of mucos membranes can easily occur which can lead to changes in permeability, swelling and inflammation.

Constriction of the bronchi: muscle cramps (spasms), swelling of the mucus membranes and increased mucus production (asthma) also become more commonplace. The alveoli are very sensitive and can easily become damaged and scarred by the intrusion of the microscopic PM2.5 particles. Local inflammatory reactions and permanent changes in cell membranes are often diagnosed as are detrimental effects on the cardiovascular system.