Analysing the implications of the 2021 amendments to WHO air quality guidelines for PM2.5

Abstract

PM2.5 pollution has been considered the most hazardous air pollutant to human health. It impacts the respiratory system, causing acute lower respiratory diseases, lung cancer and chronic obstructive pulmonary disease. It can also cause problems related to the cardiovascular system, such as ischemic heart disease and stroke. While there has been a decrease in PM2.5 concentration in the past few years, the annual concentration of this pollutant in Malta is more than twice the Air Quality Guideline set by the WHO. According to the latest scientific information, this guideline represents the threshold at which PM2.5 attributed mortalities would decrease substantially. Through this study, mortalities attributed to PM2.5 have been estimated, and emission reduction requirements were explored. Population data from the National Statistics Office, mortality data from the Directorate for Health Information and Research, and air pollution data from the Environment and Resources Authority were used to establish the mortalities that could be attributed to PM2.5 in 2019. The WHO’s AirQ+ software was used to estimate the mortalities. Following this, emission inventories and emission projections for 2025 and 2030 were used to model two pollution scenarios for 2025 and 2030. This showed that even with additional measures being taken, Malta would not reach the limit value of 10 µg/m3 proposed by the European Commission in its revision of the Ambient Air Quality Directive but would only successfully reduce the pollutant concentration to 10.1 µg/m3. Following this, mortalities were estimated again, and a slight percentage decrease between 2019 and 2025 (7.02%), as well as 2019 and 2030 (19.30%), was observed. However, there was a far more significant percentage decrease in mortalities between 2019 and a scenario where the 5 µg/m3 Air Quality Guideline has been reached (63.16%). Given that Malta would not be able to reach the AQG or the European Commission 2030 limit, stricter environmental regulations need to be adopted both on a national front and an EU-wide front. Furthermore, more effective pollution control measures need to be implemented.