Air quality researchers from the Department of Geosciences at the University of Malta, Dr Sara Fenech and Dr Noel Aquilina, have recently published a study focusing on the changes in airborne pollutant levels across the Maltese Islands between 2008 and 2017.
Air pollution data was obtained from the Air Quality Network operated by the Environment and Resources Authority (ERA) recorded at three monitoring stations in Malta (Kordin, Msida and 呕ejtun) and one station in Gozo (G魔arb).
Air pollution data was obtained from the Air Quality Network operated by the Environment and Resources Authority (ERA) recorded at three monitoring stations in Malta (Kordin, Msida and 呕ejtun) and one station in Gozo (G魔arb).
The European Union sets limits and targets for key air pollutants which Malta as member state must reach. These key air pollutants include both gases, for example ozone (O3 ) and nitrogen dioxide (NO2) as well as particulate matter (PM) of different size ranges (PM2.5 - PM10 ).
Results show that annual PM10 levels at the traffic site of Msida are above the annual EU limits of 40 碌gm-3 between 2008 and 2012 and in 2016. In addition, annual mean PM10 levels are all above the more stringent World Health Organisation (WHO) air quality guideline of 20 碌gm-3. In contrast, annual PM2.5 concentrations are within the EU limits however, these also generally exceed the annual WHO limit of 10 碌gm-3. Apart from 2008, annual NO2 levels were within the EU limit of 40 碌gm-3 between 2009 and 2017. Ozone-related EU exceedances were recorded between 2008 and 2015 at the rural background station of G魔arb reaching a maximum of 82 instances in 2011.
Statistically significant decreasing trends in PM10 and PM2.5 concentrations for the study period are noted for the majority of the stations. However, for particulate matter defined as the course fraction (PM2.5-10), results show a statistically significant increasing trend at the traffic site of Msida which is linked with an increase in the local source contribution such as traffic. Overall statistically significant increasing trends in O3 concentrations are noted across the islands while NO2 trends are not statistically significant.
Long-term exposure to air pollutants can cause various adverse health impacts such as lung cancer, cardiopulmonary diseases, exacerbation of asthma as well as mortality. Apart from studying trends of airborne pollutant levels the implications of PM2.5 and NO2 concentrations on all-cause mortality have also been analysed for each year. It is estimated that across the Maltese Islands between 5.6 to 11.7% of the all-cause mortality are associated with long-term exposure to PM2.5 and between 0.7 to 5.4% of the all-cause mortality are associated with long-term exposure to NO2.
This work is the first to outline changes in air pollutant concentrations in the Maltese Islands in the last decade. In addition, the importance of future research to focus on the sources leading to increasing trends in air pollutant concentrations is highlighted. This research gives a clear indication of the local health impacts associated with these levels and emphasises the districts that would benefit most from future mitigation and adaptations strategies.
Photo Credits: Environment and Resources Authority (ERA)
