A detailed perspective of marine emissions and their environmental impact in a representative Indian port

Abstract

Rapid economic growth has contributed to India's rising share in international trade. An increase in the number of ships visiting the port areas would enhance marine emissions, which would be harmful for densely populated port areas in India. The study developed a comprehensive emissions inventory for years 2011–2019 of air pollutants and greenhouse gases (CO2+CH4+N2O) from shipping vessels for Kolkata Dock System. The results revealed significant emissions from ocean-going vessels (OGVs), which currently do not follow the regulatory sulphur limit (0.5% m/m) as stated in Annex-VI and its amendmentsas mandated by the International Maritime Organization's Prevention of Air Pollution from ships. The study revealed a notable increase of total annual marine NOx emissions from 1,488 tons to 2,074 tons during 2011–2019, a significant growth of 28%. The forecasted values of emissions using time series model ARIMA for year 2019–20 exhibit a rise of 11% from observed values of previous year. Different emission control strategies such as fuel substitution with higher grade fuel or low sulphur diesel fuel and alternative fuel such as liquefied natural gas (LNG) led to notable reduction of emissions for both air pollutants and greenhouse gases. This signified that if emissions were unregulated there would be noticeable growth every year. The study also estimated the environmental impact of air pollutants and greenhouse gases using dispersion model AERMOD. The modeled NOx and SOx concentrations from marine vessels constitute maximum impacts of (15–20)% and (32–55)% respectively of total concentrations at two monitoring sites located within 4 km of Kolkata docks. Emissions controlled modeled runs show marked reductions of NOx, SOx and greenhouse gases concentrations. The directionality of emission controls would enable ports to introduce policies and programs to address the issues of marine emissions and facilitate sustainable growth.