A Cnr-Isac survey, based on recent studies, shows that the latest international regulations have led to a reduction in emissions of air pollutants, thanks to which a decrease in premature deaths and cases of childhood asthma due to shipping are estimated in the coming years, but also a slight increase in global warming. The findings are published in the journal Atmosphere.
A recent WHO study identifies maritime activities among the six major anthropogenic emissive sources (out of sixteen) of air pollutants, both gaseous and in the form of particulate matter, such as nitrogen and sulfur oxides and atmospheric particulate matter of different sizes. These pollutants, in particular sulphur dioxide emissions, cause acid rain and create fine dust that can cause respiratory and cardiovascular diseases.
The analysis conducted by the Institute of Atmospheric and Climate Sciences of the National Research Council (CNR-Isac) of Lecce, entitled 'Recent Advances in Studying Air Quality and Health Effects of Shipping Emissions' and published in the journal Atmosphere, examines current knowledge on the impact of local navigation in port areas comparing them with public health indicators.
"In Europe, the impact on concentrations of pollutants in the atmosphere, such as PM2.5 and PM10, the so-called fine dust, varies between 0.2% and 14%, with the highest values observed in the Mediterranean area", says Daniele Contini, Cnr-Isac researcher and co-author of the research together with the colleague Eva Merico. "In Italy there are impacts on fine dust is typically between 2% and 10%. The impacts on gaseous pollutants (nitrogen oxides and sulphur oxides) are even greater and vary, in Italy, typically between 5 and 40%, the highest values are detected in the proximity of port areas".
The latest international regulations establishes a drastic reduction in the sulphur content of marine fuels, from 3.5% to 0.5% in mass, thus leading to a reduction in emissions of sulphur oxides and atmospheric particulate matter. "Thanks to these measures, it is possible to estimate a decrease in the coming years of 34% of premature deaths due to shipping emissions (which would still remain 250 thousand per year) and 54% of cases of childhood asthma", concludes Contini. "On the other hand, the reduction of the sulphur content in fuels changes the chemical and physical properties of the emitted particulate matter and therefore its interaction with solar radiation, reducing the cooling effect of the aerosol emitted by ships and leading to an increase of about 3% in the global warming forcing due to human activities, with an overall negative effect on the climate. It is therefore desirable that future environmental policies, aimed to maritime traffic, will consider and protect both these aspects, health and climate."
Contini D, Merico E., (2021) Recent Advances in Studying Air Quality and Health Effects of Shipping Emissions, in "Atmosphere" 12(1), 92, https://doi.org/10.3390/atmos12010092