U.N. to Issue Guidelines for Reporting Black Carbon Emissions for Global Inventory

ST. PETERSBURG, Russia--A work group under the United Nations Economic Commission for Europe (UNECE) is set to issue the first standard guidelines for estimating and reporting black carbon emissions, a step toward creating an international inventory for the pollutant.

The inventory will be created under the Convention on Long-range Transboundary Air Pollution’s Gothenburg Protocol. Parties to the protocol, including the United States, Canada, and the European Union, will be required to report their black carbon emissions estimates. Countries in Eastern Europe, including Russia and Ukraine; Central Asia, including Kazakhstan and Uzbekistan; and the Caucasus are also expected to sign on to the protocol and undertake the reporting requirements (35 INER 1163, 12/5/12).

Black carbon is composed of fine particles produced from the incomplete combustion of diesel fuel, wood, crop waste and other biomass, oil, refuse, and in some cases coal. Evidence indicates that black carbon contributes to climate change by warming the atmosphere and by darkening the surface of snow and ice, speeding melting. It also poses problems for human health, including respiratory and cardiovascular effects.

The black carbon emissions inventory will cover a wide range of sources, which will likely include transportation, energy generation, residences, manufacturing, waste, agriculture, and shipping. The inventory will help in forming policies to reduce levels of the pollutant.

The UNECE Task Force on Emission Inventories and Projections has created standard methodologies for black carbon emissions inventories, which it will discuss and make publicly available at its next meeting May 13-15 in Istanbul.

The black carbon methodologies are expected to be approved this year at a September meeting of the steering body of the air pollution convention's European Monitoring and Evaluation Program (EMEP).

The methodologies will then be added to the Emission Inventory Guidebook used by parties to the UNECE air pollution convention to make their data consistent and comparable.

Black Carbon Growing Concern

Parties to the UNECE air pollution convention responded to the growing science identifying black carbon as both an important air pollutant and a contributor to climate change by adding it to the list of pollutants controlled under the Gothenburg Protocol in May 2012. Reporting national emissions estimates for black carbon is the first mandatory requirement for the pollutant (35 INER 461, 5/9/12).

Sulfur, nitrogen oxides, volatile organic compounds, ammonia, and particulate matter are also controlled under the protocol. Countries set their own control requirements for the pollutants. For example, the United States meets its requirements under the protocol through the national ambient air quality standards.

Since May 2012, research has suggested that black carbon is even more important than previously thought. A report, Bounding the Role of Black Carbon in the Climate System, published in the Journal of Geophysical Research: Atmospheres in January, concluded that black carbon is the second largest climate warmer after carbon dioxide. The study was the product of a multiyear review with support from the International Global Atmospheric Chemistry project (36 INER 165, 1/30/13).

Black carbon is also seen as particularly significant because it is a so-called short-lived climate forcer, meaning that warming effects stop when emissions are eliminated. Thus targeting the pollutant is seen as essential to slowing climate change in the near term.

Kristina Saarinen, co-chairwoman of the Task Force on Emission Inventories and Projections and a team leader in the Air Emissions Division of the Finnish Environment Institute, told BNA April 12: “Black carbon has many impacts that were not taken into account in the earlier days. It has climate effects, and health effects, and air pollution effects. Until now, we had an inventory of total particles, and we then went to PM-10 [particulate matter smaller than 10 microns in diameter] and then PM-2.5, and now we have realized that there are more important particles, like [ultrafine particles] and black carbon, and we are now trying to look at those, too.”

The new methodologies could result in changes to current emission estimates in some sectors as countries revise their existing data to conform.

Saarinen said under the Convention on Long-range Transboundary Air Pollution, countries will start officially reporting black carbon emissions in 2015, though some will likely start reporting in 2014.

By Jenny Johnson