## 4 Conclusions  
Maritime shipping's emissions are significant air pollutants that cause public health and food production problems, in addition to climate change. In Italy, as elsewhere, the emissions vary among industry segments and among locations. Until the coronavirus pandemic of 2020, cruise ships were a major air polluter in Italian ports and along its coasts. By late 2020, there were signs that the cruise segment of maritime shipping was beginning to resume operations on a small scale, though with doubts about how many years it would be before it regained much of its lost business. In ports, it is not only the ships' emissions that contribute to the problem, it is also the emissions of the port loading and unloading equipment, as well as the truck and rail traffic that connects to the marine traffic in the port areas. Diesel engines are the common element in all of these sources of emissions, whether in ports, along coasts or on the high seas. Because of black carbon's three kinds of impacts (climate, health and food), reductions of BC emissions offer three kinds of corresponding benefits. The potential resulting co-benefits of one emission reduction measure make such measures economically and politically attractive. In addition, the effects of mitigating BC emissions are evident virtually immediately as visible black smoke plumes diminish with the implementation of the emission control measures. The time scale of a matter of days for the effects of BC reductions to occur contrasts with the decades and centuries for the effects of carbon dioxide emission reductions. Further, the reductions of shipping's BC emissions occur locally and regionally as well as globally. The local and regional benefits to human health and food production are direct consequences of the emission reductions, and the local and regional health and food production benefits are enjoyed by local and regional inhabitants. The 'free rider' problem of reducing global warming forcing agents is thus largely circumvented by localized and regionalized emission reductions, though there is still some free-riding because of the global benefits of reducing global warming emissions. There are diverse operational and technological solutions that can reduce BC and other emissions, and there are governmental policies that can create incentives for industry participants to change their operational and technological choices. Italian shipbuilders, owners, and operators are all therefore encountering expanding options to address maritime emissions issues. Their choices will of course be influenced by technological and economic factors. As this paper and others' analyses have been suggesting for the past several years, the maritime shipping industry is in the midst of overlapping technological revolutions, including, in particular, propulsion technologies and information processing technologies. As technologies change, so also do the economic cost-benefit calculations of industry participants and governmental policymakers. Those industry options and decisions are also influenced by policymaking processes at all levels of governance. Potential governmental policy changes are on the active agendas of the International Maritime Organization, the 22 countries that are signatories of the Convention for the Protection of the Mediterranean Sea against Pollution (i.e., the Barcelona Convention), and the 27 countries of the European Union, as well as other European countries such as Norway and the UK with significant stakes in international maritime shipping. The Italian national government is of course a participant in all these fora. It has already taken a leadership position, along with France and Italy, on the creation of a Mediterranean Emission Control Area (Med ECA). However, in order to address the maritime black carbon emission problem in Italy and the other Mediterranean coastal countries, black carbon needs to be covered in a Med ECA.