Updated 6.10pm with ERA statement

Data indicating air pollution in Żejtun was 20 times above safe limits was due to "faulty equipment" and therefore incorrect, the town mayor has said. 

Readings from the Żejtun air monitoring station – retrieved from the European Air Quality Index – showed concentrations of fine particulate matter, known as PM2.5, averaging around 500 micrograms per cubic metre since at least March 4.

According to World Health Organisation guidelines, 25 micrograms is the limit for healthy exposure over a 24-hour period.

However, mayor Maria Dolores Abela told Times of Malta that she had spoken to the Environment and Resources Authority, which operates the monitoring station, and been assured that the readings were erroneous and caused by faulty equipment. 

The ERA in a statement two hours later, confirmed that the air monitoring station is giving anomalous readings.

It said it is conducting tests on the PM 2.5 analyser, which, in the meantime, has been disabled.

Notwithstanding, the Żejtun Air Monitoring Station will still continue transmitting the rest of the air monitoring data 24/7.

Third-party websites, such as the European Environment Agency’s (EEA) website, may still be showing data that is automatically sent by ERA’s stations. This data includes the PM 2.5 data from the faulty analyser. The correct data will be transmitted once the issue has been solved, the ERA said. 

The ERA said it will issue an official notification once the system is fully functional.

ERA's air monitoring data is accessible online at

Nationalist Party environment spokesman Jason Azzopardi was quick to highlight the delay before an official explanation.  

"After more than eight hours, the Environment Ministry has not yet set people's minds at ease," he said in a statement issued before the press statement by the environment authority. 

Experts who spoke to the Times of Malta on Sunday had warned that the data could be misleading, with no immediate cause that could account for such a sudden spike in pollution readings. 

Fine particulate matter has a major impact on human health, according to the EEA, aggravating heart and lung disease and posing a serious threat to respiratory health for the general population.

The US Environmental Protection Agency defines anything above 250 micrograms as “hazardous” and recommends that everyone should avoid outdoor exertion, while those with respiratory or heart disease, as well as the elderly and children, should remain indoors.

The data should set alarm bells ringing

Experts were perplexed by the readings

Martin Balzan, a respiratory health expert, told the Times of Malta PM2.5 readings at the Żejtun station were typically low due to the gas-fired power station and prevailing winds in the area.

He noted that the cause of the spike was unlikely to be traffic, as nitrogen dioxide levels had not increased, and cautioned that the readings could be an error or the result of an extremely localised event, such as a traffic detour or fireplace output close to the monitoring station’s sensors.

Engineer Arthur Ciantar, who has studied air quality in the area, said he could not recall such high levels of fine particulate matter before. Increases, he said, were most often caused by traffic, highlighting marine traffic and trans-boundary pollution as other contributing factors.

He added that, if accurate, the data should set alarm bells ringing and highlight the consequences of the region’s significant increase in traffic density.

A European Environment Agency report published last October found that Malta had the fourth worst levels of particulate matter in the EU – 50 micrograms per cubic metre, right at the European daily limit.

The report also found air pollution was responsible for 250 premature deaths in Malta in 2014.

A 2016 study by Dr Balzan and Michael Pace Bardon from the Department of Medicine at Mater Dei found pedestrians and cyclists in Fgura were exposed to three or four times more black carbon on the streets than indoors.