15 The Committee is also encouraged to consider including limits for hydrocarbons (HC) and diesel particulate matter (PM). In addition to being a contributor to ozone formation, hydrocarbons include a number of hazardous air pollutants that are known or probable human carcinogens. Because HC emissions may actually increase as NOx limits are tightened, as engine manufacturers recalibrate emissions by focusing only on NOx, the Committee should at least consider capping HC emissions to avoid emissions backsliding. There is a similar trade-off effect between NOx and PM controls. This is of special concern both because diesel engines have high PM levels and because of a growing body of research that associates diesel PM with serious respiratory problems. Several agencies and governing bodies have also designated diesel exhaust or diesel PM as a 'potential' or 'probable' human carcinogen.5 Thus, the concern for diesel exhaust influences on human cancer hazard is widespread.
Action requested of the Committee
16 The Committee is invited to consider the above views, and begin a dialogue to establish a second tier of emission limits for marine diesel engines. The Committee is further invited to ask the drafting group (DG1) on air pollution to consider what changes to the NOx Technical Code would be necessary to establish a second tier of emission limits and to report its views to the Committee.
5National Institute for Occupational Safety and Health (1988) Carcinogenic effects of exposure to diesel exhaust. NIOSH Current Intelligence Bulletin 50. DHHS (NIOSH) Publication No. 88-116. Centers for Disease Control, Atlanta, GA. National Institute for Occupational Safety and Health (1988) Carcinogenic effects of exposure to diesel exhaust. NIOSH Current intelligence Bulletin 50. DHHS (NIOSH) Publication No. 88-116. Centers for Disease Control, Atlanta, GA; International Agency for Research on Cancer (1989) Diesel and gasoline engine exhausts and some nitroarenes, Vol. 46. Monographs on the evaluation of carcinogenic risks to humans. World Health Organization, International Agency for Research on Cancer, Lyon, France; World Health Organization (1996) Diesel fuel and exhaust emissions: International program on chemical safety. World Health Organization, Geneva, Switzerland; Office of Environmental Health Hazard Assessment (1998) Health risk assessment for diesel exhaust, February 1998. California Environmental Protection Agency, Sacramento, CA; National Toxics Program (1998) Report on carcinogens: Background document for diesel exhaust particulates. U.S. Department of Health and Human services, Research Triangle Park, NC.
