Qualité de l’air à Legnica

What is the current level of air pollution in Legnica city?

Legnica is a city in south-western Poland, in the central part of Lower Silesia, on the Kaczawa River (left tributary of the Oder) and the Czarna Woda. According to a census which was conducted in 2019, Legnica had an estimated population of approximately 100,000 inhabitants.

During September 2021, Legnica was experiencing a period of “Moderate” air quality with a US AQI reading of 61. This United States Air Quality Index number is calculated by collecting data from the six most prolific air pollutants which are usually; nitrogen dioxide, sulphur dioxide, ozone, carbon monoxide and both sizes of particulate matter, which are PM2.5 and PM10. This can then be used in comparison when studying other cities from any location. If not all six figures are available, a figure can still be calculated by using what data is available. In the case of Legnica only PM2.5 was recorded which was 17 µg/m³. This level is just over one and a half times above the recommended target figure of 10 µg/m³ which was suggested by the World Health Organisation (WHO). The given advice therefore would be to close doors and windows to prevent the ingress of more polluted air. Those who are sensitive to poor air should try to remain indoors as much as possible until the air quality improves. For up-to-date information as to the state of the air, there is a downloadable app from AirVisual which is available for all operating systems.

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

The air that we breathe can be very volatile because it is affected by many variables. Atmospheric and meteorological conditions play a powerful part in air quality.

Looking back at the figures for 2020 as published by IQAir.com, it can be seen that for 11 months of the year, Legnica experienced “Moderate” air quality with readings between 12.1 and 35.4 µg/m³. The month with the dirtiest air was December with a reading of 30.7 µg/m³. The cleanest month was May with 12.4 µg/m³. The month of July attained a reading within the target range as stipulated by the World Health Organisation (WHO) of 10 µg/m³ or less.

There were no records kept before 2020 when the average annual figure was 17 µg/m³ which classed the air quality as being “Moderate”. This figure 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 the air pollution in Legnica?

The permissible frequency of exceeding the target level has not been exceeded. The tropospheric ozone measured at the stations is formed near the earth's surface, mainly in summer with high insolation, temperature and pressure. In Legnica, the highest concentrations were recorded in the summer season, in June and July. Analyses of measurement data from many years do not show significant trends in changes in the level of ozone concentrations.

In 2019, the average annual standard for suspended dust PM10 was not exceeded. The annual average concentration of PM10 dust at the station Rzeczpospolita was 28.5 µg/m³ so 71 per cent which is an acceptable level. In 2019, the value of PM10 particulate matter decreased compared to previous years. In the last decade (since 2010), annual concentrations have dropped by 36 per cent, and the number of days with exceedances - by 52 per cent.

Measurements of suspended dust PM2.5 carried out at the station at Polarna, did not exceed the average annual norm, and the average annual concentration was 17 µg/m³, i.e. 68 per cent of the standard, amounting to 25 µg/m³. The analysis of annual average concentrations from 2010-2019 shows a noticeable decrease in the PM2.5 dust level.

The concentrations of lead, cadmium and nickel in 2005–2019 remained at a low level. In 2019, there was a significant decrease by 29 per cent, in the average annual arsenic concentration (below the target level).

What can be done to reduce air pollution in Legnica?

Last year, in Legnica, the emission of PM10 was reduced by 35.3 tons and PM2.5 by 16.3 tons. This was due to the thermal modernisation of facilities carried out by the city, property managers, housing cooperatives and the Legnica low-emission reduction program. As part of it, residents obtained co-financing from the commune for the replacement of old heat sources, using solid fuel, with ecological sources, e.g. connection to the heating network or electric or gas heating.

The reduction of dust emissions in 2019 was also influenced by measures taken by the Municipal Roads Authority in Legnica, consisting in cleaning the streets. Roads with a total length of 135.25 kilometres were cleared. This had a concrete ecological effect in the form of an annual reduction of PM10 dust emissions by 25 tonnes and PM2.5 dust emissions by 3.8 tonnes.

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

Particulate matter is a particularly important substance in the air from the point of view of protecting our health and life. A dust whose particles have an aerodynamic diameter of less than 2.5 micrometres (µm) is termed PM2.5; we define PM10 dust similarly. PM is short for particulate matter.

How strongly dust pollution affects health depends not only on its concentration in the air and the time of exposure (i.e. the total amount of pollution that enters our body), but may also depend on the size, shape and chemical composition of dust particles. The chemical composition of dust, in turn, strongly depends on its origin. While there is strong evidence of adverse health effects from fossil fuel or biomass combustion dust, the significance of exposure to mineral dust (dust from soil erosion or desert dust) is less certain. Dust from the combustion of coal, petroleum derivatives or biomass may contain various substances harmful to health, e.g. carcinogenic and mutagenic polycyclic aromatic hydrocarbons (PAHs) and their derivatives.

Gaseous pollutants, such as carbon monoxide (CO), sulphur dioxide (SO₂), nitrogen dioxide (NO₂), and tropospheric ozone (O₃) formed from nitrogen dioxide in photochemical reactions, also have a harmful effect on health. Usually, we are dealing with simultaneous exposure to gas and dust pollutants.