Slovenia's air pollution mapped

Celje most polluted city, but getting cleaner

With a toxic industrial legacy, Celje stood out last year as the only location in Slovenia to exceed limit daily PM10 concentrations more than the allowed 35 times a year.

The limit 24-hour mean concentration of PM10 particles, set at WHO guideline value of 50 microns per cubic metre (ug/m3), was surpassed on 42 days, which compares to 35 days in 2018, 49 in 2017, 52 in 2016 and 70 days in 2015.

Excessive concentrations are recorded mainly in winter, when heating adds to other sources of pollution. Another downside is Celje's location in a basin where air pollution is aggravated by temperature inversions in winter.

Local authorities say the city will breathe cleaner air once they have implemented all sustainable mobility projects, and when the state builds a bypass to divert transit traffic out of the city.

To improve its air, the city is expanding its gas pipeline network and district heating system, renovating public buildings to make them more energy efficient and expanding its bicycle sharing system.

It has bought ten compressed natural gas city buses and built a modern filling station with a new park and ride facility to open on the city's outskirts by summer.

Environment Agency data show major air polluters in Celje are the Merkscha veneer mill and chemical company Cinkarna Celje, both of which say they have modernised to reduce emissions.

The mill says it has reduced annual dust emissions from 84 tonnes in 1974 to an average 13 tonnes a year, while Cinkarna says it has reduced its dust emissions by 69% since 2008.

Ljubljana improving its air

City authorities say that air quality in Ljubljana is good; above-limit particle pollution is recorded only occasionally during the heating season. The main challenge outside that season is traffic.

Three out of four homes in the capital are connected to the district heating systems, so pollution in winter is mainly due to household heating on the outskirts.

The Ljubljana-Centre monitoring station recorded an annual mean value of 34.4 PM10 ug/m3 last year, down from 35.8 in 2018; the number of days on which the limit was exceeded dropped from 51 to 37.

The value of PM2.5 stayed at 21 ug/m3, the limit being 25 ug/m3, and the average annual concentration of nitrogen dioxide (NO2) was reduced from 48 to 45.3 ug/m3, the limit being 40 ug/m3.

The Ljubljana-Bežigrad monitoring station, which is representative for the whole city, recorded the annual mean for PM10 dropping from 26.9 to 23.2 ug/m3 and the number of above-limit days reduced from 28 to 16.

The annual mean for PM2.5 fell from 19 to 17 ug/m3 and the annual NO2 mean fell from 25.7 to less than 25 ug/m3 although data for December are not available yet.

The key step to improving the city's air was the closure of a section of Slovenska Cesta thoroughfare to all traffic except for buses and taxis. "Measurements show the value of black carbon there has dropped by 70% compared to background area [Vojkova Street], nor have values at surrounding roads increased," city authorities say.

Apart from implementing the sustainable mobility strategy and promoting cycling and walking, a key measure ahead will be a new gas steam power station to replace two out of three coal units at the TE-TOL co-generation plant.

The EUR 130 million investment is to allow the city to replace 70% of coal with natural gas by the end of 2022. Coal is to be fully phased out at TE-TOL in the future.

Under a private-public partnership signed in 2017, 48 public buildings in the municipality are to be renovated to improve their energy efficiency at the cost of EUR 14.9 million, VAT excluded, to save 8.25 million kilowatt hours of energy or over EUR 1 million a year.

Maribor air improving, not yet matching guidelines

Slovenia's second city has been improving its air pollution track record, but PM10 values are still above WHO guidelines, in particular in winter. Between January and November 2019, daily values in the centre were above the limit on 10 days, which compares to 30 the year before.

The city authorities say that the concentrations measured in recent years have been the lowest since 2001, which they attribute to the many measures taken, in particular in sustainable mobility and heating.

However, emissions from industrial sources have almost doubled over the past decade, which is due to new companies mushrooming up in business zones on the sites of once large companies that went bankrupt after independence.

The register of fixed air pollution sources shows the car parts maker Cimos Tam as by far the largest generator of dust, with other major polluters being bread and pasta company Žito, abrasives maker Weiler, Maribor foundry and the hydraulic lifting systems maker Palfinger.

Maribor also gets 13% of all traffic emissions in the country. On the city's periphery the main problems is emissions from individual household heating devices.

Among other measures taken, the city is planning to electrify public passenger transport and expand the network of cycling paths and pedestrianised zones. The city is served by a hybrid bus and a small plug-in passenger vehicle called Maister, which is free to use.

In a public-private partnership and with the help of EU funds, 24 public buildings have been renovated to improve their energy efficiency, including schools, kindergartens and sports and ice rink arenas. The city is also expanding its district heating and gas networks.

Murska Sobota introducing automatic pollution notification

One of the areas with the highest levels of PM10 in the country, Murska Sobota saw the limit daily value exceeded 28 times last year, down from 46 in 2018. The data are from one of the two monitoring stations, with two more to be added soon.

The city is also introducing a smart sensor system to alert residents when to keep indoors due to excessive concentrations of air pollutants. Kindergartens, schools, nursing homes and other public institutions will get notifications automatically.

Based on the data gathered, city authorities will implement further measures to reduce PM10, including energy overhaul of buildings. The main sources of pollution are household furnaces and traffic.

The city has been promoting the use of public transportation, cycling and walking, slowing down traffic, securing its smooth flow, creating pedestrianised zones and expanding cycling paths and green areas.

Zasavje major particle pollution hotspot

The former mining and industrial region of Zasavje in central Slovenia remains one of the most heavily polluted regions in the country, the main reasons being emissions from industry, household furnaces and traffic, coupled with adverse meteorological conditions.

All of the region's major towns - Trbovlje, Zagorje ob Savi and Hrastnik - are located in the narrow, poorly ventilated valleys along the Sava River, which means that temperature inversion keeps polluted air close to the ground.

The Environment Agency (ARSO) has been recording a decline in annual mean concentrations of PM10 since 2002 as a result of lower emissions and purification systems at industrial facilities.

Last year the daily threshold PM10 values were exceeded 28 times in Zagorje, 16 times in Trbovlje and 9 times in Hrastnik.

But while ARSO data show that Hrastnik air is getting cleaner, those from the National Public Health Institute show the town had the highest death rate attributable to air pollution in the country between 2016 and 2018.

The local authorities argue that the data obtained from the ARSO monitoring station, located in a sports park away from sources of pollution, is not realistic. However, their appeals to ARSO and the Environment Ministry to relocate the station and set up additional ones has not been heeded.

In Trbovlje, the biggest source of PM10 are small household combustion installations. The biggest industrial polluter in the region used to be the cement plant, part of the Switzerland-headquartered multinational LafargeHolcim, which suspended production in 2015

The Hrastnik chemical company TKI would not disclose its air improvement measures for the STA, while the glassworks Steklarna Hrastnik as a major Zasavje polluter pointed to its investment into innovation and greener production.

Novo Mesto yet to see significant improvement

Novo Mesto saw the threshold daily PM10 concentration exceeded 18 times last year, which is on a par with previous years. City authorities say that this means that more effort by everyone involved will be needed to achieve meaningful improvements in air quality.

To help plan further measures and evaluate the results of those already taken the city set up own air quality monitoring devices at 14 additional locations last year.

Household heating devices are blamed for two thirds of coarse matter particle emissions, with the other major source being road traffic.

The city has been investing intensively in sustainable mobility projects, including by switching to gas- and electricity-powered public transportation, putting in place plug-in infrastructure for cars and promoting walking, cycling and car sharing.

Like in other parts of the country, measures to modernise household heating systems are being taken with the help of subsidies from the Eco Fund.

Šalek Valley air cleaner, concerns about waste incineration at TEŠ

Air quality in the Šalek Valley (NE) has improved since the launch of generator 6 at the Šoštanj coal-fired power plant (TEŠ) in June 2015. However, the plant's plans to replace part of coal with waste as fuel are causing public concern.

TEŠ says it has reduced CO2 emissions by 30% and substantially cut dust emissions. After the overhaul of the substitute unit 5 in 2017 and 2018, SO2 emissions have been halved compared to the recently phased out generator 4, NO emissions have been reduced by 60% and particle emissions by 80%.

The plant is considering waste co-incineration, which it says would reduce rather than increase the harmful impact on the environment. Its analyses show that 160,000 tonnes of alternative fuel would equal to 215,000 tonnes of fossil fuel, reducing SO2 emissions by 156,000 tonnes a year, with other emissions kept within permitted values.

The local environmental movement opposes the plans, arguing that co-incineration would "cancel out the first positive steps to improving the air". The movement also says that emissions from generator 5 show TEŠ has not met the cuts promised when planning unit 6.

The movement is collecting signatures against co-incineration, and a civil initiative is planning to challenge waste incineration in a referendum.

Kranj removed from air pollution blacklist

Kranj, Slovenia's fourth largest city, used to be one of the category 1 particle pollution areas in the country, but its air has since improved so that in February 2019 it exited the national air quality improvement programme.

The city has been focusing on measures to reduce emissions from building heating and road traffic. In a EUR 6.2 million project subsidised by EU cohesion funds, 22 public buildings have been renovated to reduce CO2 emissions by 1,300 tonnes a year.

Other measures include those aimed at improving traffic flow and promoting sustainable mobility with the first P+R and an integrated passenger terminal in the pipeline, along with the expansion of cycling paths and its cycle share network, the biggest e-bike system in the country.

Mayor Matjaž Rakovec is proud on the improvements, pledging for the efforts to continue. Residents can follow air quality monitoring at three most pollution-prone spots in the city.

Traffic major source of pollution on coast

Although the port town of Koper does not rank among areas with above-limit levels of air pollution, it does exceed limits at times, the main reason being transit traffic during the summer season.

Emissions from the city's dense road network rise several-fold in summer when the situation is compounded by ozone pollution.

As yet incomplete data from ARSO show hourly ozone warning limits in Koper were exceeded four times in 2019, all in June, while the daily 8-hour target level was surpassed 44 times, above the 25 permitted.

The daily PM10 mean concentration was exceeded 8 times in 2019, four times in 2018 and 18 times in 2017.

The city has made steps to reduce pollution, including measures to slow down traffic, expand green areas and promote green mobility, but local official say that the traffic problem may be solved comprehensively only in cooperation with the neighbouring communities and the national government.

The city has renovated more than half of all public buildings and partly refurbished 90% of buildings under its management in recent years to improve their energy efficiency.

PM10 levels are also monitored at the Koper port, but the operator Luka Koper says the values at the port are much lower than in many other parts of the country.