Emission Control Area (ECA) 

This page last reviewed August 17, 2011


The International Maritime Organization (IMO) has designated waters off North American coasts (including California) as an Emission Control Area (ECA), in which stringent international emission standards will apply for ships. These standards will dramatically reduce air pollution from ships and deliver substantial air quality and public health benefits that extend hundreds of miles inland. Ocean-going ships burn high-sulfur fuel oil at cruise, thereby emitting relatively large amount of sulfur dioxide. An increase in international trade would lead to an increase of ship emissions of air pollutants, including sulfur dioxide and sulfate. Because California has a long coastline, large ports, and heavily populated coastal areas, ship emissions may significantly elevate population-weighted air pollutant concentrations, thereby contributing to adverse health impacts, visibility degradation, and ecological impacts through acid deposition. More information about the North American ECA is at the U.S. EPA's 'ocean vessels' website.

In 2005, the U.S. EPA, along with its Canadian and Mexican partners, began developing technical information for a potential ECA application to the IMO. The goal was to quantify the health and welfare impacts of commercial marine vessels (CMV). CARB was the lead agency and the primary point of contact to U.S. EPA for the West Coast. The West Coast partners made a case for the need to reduce sulfur in diesel fuel to mitigate particulate matter (PM) health impacts. Because of expected uncertainties in modeling of offshore transport and transformation of CMV emissions, CARB funded and performed complementary modeling and observation-based approaches. The purpose was to assess the health benefits of controlling ocean-going ship emissions of gas-phase sulfur dioxide and aerosol-phase sulfate. Following are descriptions and links to documents on ECA activities by CARB and for CARB-funded research conducted between 2002 and 2010.

Research Projects:

  • Commercial Marine Vessel (CMV) Emissions Inventory

CARB funded Prof. James Corbett (Univ. Delaware) to model North American inter-port emission inventories in 2002, 2010 and 2020 with low-sulfur scenarios in 2020, using data from the International Comprehensive Ocean-Atmosphere Data Set (ICOADS). The regional inventories were produced from the GIS-based Ship Traffic, Energy and Environment Model (STEEM), and compared with port-specific CMV inventories in Los Angeles as well as other areas of the North America. The Phase 1 final report: Estimation, Validation, and Forecasts of Regional Commercial Marine Vessel Inventories was completed in 2007, and the Phase 2 final report: Improved Geospatial Scenarios of Commercial Marine Vessels was completed in 2010.

  • Ambient Measurements

  1. CARB funded Prof. Ian Faloona (UC Davis) to conduct ambient monitoring of CO and ozone at the Bodega Bay Marine Lab on the Northern California coast that provides baseline air quality data for the offshore environment. Detailed analysis of the shoreline pollutant data and the collocated meteorological data enabled an improved estimate of offshore CO emissions and boundary layer heights. Additionally, a preliminary survey of the local fishing community at Bodega harbor was conducted to ascertain offshore ship traffic frequency, and to develop an inventory of engine types at the local marina. The final report: An Investigation of Offshore Ship Emissions of CO from Shoreline Measurements and a Survey of Vessel Operations was completed in 2010.
  2. CARB funded Profs. Mark Thiemens and Kimberly Prather (UC San Diego) to quantify the contribution of ship emissions to air quality in the San Diego area. Isotopic measurements of aerosol nitrate and sulfate were used to develop a proxy of the impact of ship emissions in the air. Ambient data were collected on a pier using an aerosol time-of-flight mass spectrometer, and particle size distribution and gas phase measurements were also obtained. The data demonstrated significant transport of emissions from the port area of Los Angeles/Long Beach to San Diego, with a strong component likely from ship emissions. A unique particle type containing metals was identified that may be a proxy for major ship traffic. The final report: Using Single Particle Mass Spectrometry and Isotope Measurements to Determine the Contributions of Ship Emissions to Ambient PM in La Jolla, California was completed in 2008.
  • PM Source Apportionment

CARB funded Prof. Phil Hopke (Clarkson Univ.) to conduct a PM source apportionment analysis of West Coast monitoring data to assess the contribution of ship emission to ambient PM concentration at several coastal stations. They found that the presence of other sources of secondary sulfate tends to mask the production of sulfate aerosol arising from ship emissions. The final report: Analyses of PM-Related Measurements for the Impacts of Ships was completed in 2006.

  • Modeling

CARB funded Prof. Donald Dabdub (UC Irvine) to study the effects of ship emissions on air quality in the greater Los Angeles area. Analysis of model runs with and without ship emissions show that ship emissions contribute significantly to ozone and PM concentrations at many coastal locations. The final report: Air Quality Impacts of Ship Emissions in the South Coast Air Basin of California, was completed in 2008.

  • Emission Control Technology

CARB funded Drs. Hamid Hefazi and Hamid Rahai (Cal. State Univ. Long Beach) to review and evaluate methods and technologies for reducing emissions from ocean-going vehicles, including general cargo ships, passenger ships, bulk carriers, oil tankers, vehicle/roll-on/roll-off vessels, and containerships. The types of technologies reviewed include engine optimization, engine process modifications, exhaust after-treatment, and use of cleaner fuel. The final report: Emission Control Technologies for Ocean-Going Vessels was completed in 2008.

CARB Staff Report: PM Emission Factor Review

CARB staff evaluated available data to assess ocean-going vessel particulate matter (PM) emission factors. The goals were to compile available testing data, analyze potential confounding relationships in the data, and assess emission factors. PM emission factors for vessels operating on heavy fuel oil at 2.5% sulfur content were found to be significantly higher than for vessels operating on distillate fuel. The analysis identified only a weak relationship between fuel sulfur content and PM emission factors. The report: A Critical Review of Ocean-Going Vessel Particulate Matter Emission Factors was completed in 2007.

Ship ECA (SECA) Meeting

CARB hosted a Ship ECA (SECA) meeting in Sacramento, CA in 2007. Slides were presented by CARB (SECA Modeling-Central California and Health Impacts) by the University of Delaware (Emission Inventory) and by UC Irvine (SECA Modeling-South Coast).


For more information about ECA activities, please contact Peggy Taricco, Air Resources Board, Stationary Source Division: (916) 324-8496.