J. Borken-Kleefeld

Global anthropogenic emissions of particulate matter including black carbon

This paper presents the first comprehensive assessment of historical (1990-2010) global anthropogenic particulate matter (PM) emissions including consistent and harmonized calculation of mass-based size distribution (PM1, PM2.5, PM10) as well as primary carbonaceous aerosols including black carbon (BC) and organic carbon (OC). The estimates were 10 developed with the integrated assessment model GAINS, where sourceand region-specific technology characteristics are explicitly included. This assessment includes a number of previously unaccounted or often misallocated emission sources, i.e., kerosene lamps, gas flaring, diesel generators, trash burning; some of them were reported in the past for selected regions or in the context of a particular pollutant or sector but not included as part of a total estimate. Spatially, emissions were calculated for 170 source regions (as well as international shipping), presented for 25 global regions, and allocated to 0.5 o x 15 0.5 o longitude-latitude grids. No independent estimates of emissions from forest fires and savannah burning are provided and neither windblown dust nor unpaved roads emissions are included. We estimate that global emissions of PM have not changed significantly between 1990 and 2010, showing a strong decoupling from the global increase in energy consumption and consequently, CO2 emissions but there are significantly different regional trends, with a particularly strong increase in East Asia and Africa and a strong decline in Europe, North 20 America and Pacific. This in turn resulted in important changes in the spatial pattern of PM burden, e.g., European, North American, and Pacific contributions to global emissions dropped from nearly 30% in 1990 to well below 15% in 2010, while Asia’s contribution grew from just over 50% to nearly 2/3 of the global total in 2010. For all considered PM species, Asian sources represented over 60% of the global anthropogenic total, and residential combustion was the most important sector contributing about 60% for BC and OC, 45% for PM2.5 and less than 40% for PM10 where large combustion sources and 25 industrial processes are equally important. Global anthropogenic emissions of BC were estimated at about 6.6 and 7.2 Tg in 2000 and 2010, respectively, and represent about 15% of PM2.5 but for some sources reach nearly 50%, i.e., transport sector. Our global BC numbers are higher than previously published owing primarily to inclusion of new sources. This PM estimate fills the gap in emission data and emission source characterization required in air quality and climate modelling studies and health impact assessments at a regional and global level, as it includes both carbonaceous and non30 carbonaceous constituents of primary particulate matter emissions. The developed emission data set has been used in several Atmos. Chem. Phys. Discuss., doi:10.5194/acp-2016-880, 2016 Manuscript under review for journal Atmos. Chem. Phys. Published: 20 October 2016 c

Specific Climate Impact of Passenger and Freight Transport

Emissions of short-lived species contribute significantly to the climate impact of transportation. The magnitude of the effects varies over time for each transport mode. This paper compares first the absolute climate impacts of current passenger and freight transportation. Second, the impacts are normalized with the transport work performed and modes are compared. Calculations are performed for the integrated radiative forcing and mean temperature change, for different time horizons and various measures of transport work. An unambiguous ranking of the specific climate impact can be established for freight transportation, with shipping and rail having lowest and light trucks and air transport having highest specific impact for all cases calculated. Passenger travel with rail, coach or two- and three-wheelers has on average the lowest specific climate impact also on short time horizons. Air travel has the highest specific impact on short-term warming, while on long-term warming car travel has an equal or higher impact per passenger-kilometer.

Sectoral marginal abatement cost curves: implications for mitigation pledges and air pollution co-benefits for Annex I countries

Using the GAINS (Greenhouse Gas–Air Pollution Interactions and Synergies) model, we derived Annex I marginal abatement cost curves for the years 2020 and 2030 for three World Energy Outlook baseline scenarios (2007–2009) of the International Energy Agency. These cost curves are presented by country, by greenhouse gas and by sector. They are available for further inter-country comparisons in the GAINS Mitigation Efforts Calculator—a free online tool. We illustrate the influence of the baseline scenario on the shape of mitigation cost curves, and identify key low cost options as well as no-regret priority investment areas for the years 2010–2030. Finally, we show the co-effect of GHG mitigation on the emissions of local air pollutants and argue that these co-benefits offer strong local incentives for mitigation.

NOx Emissions from Diesel Passenger Cars Worsen with Age

Commonly, the NOx emissions rates of diesel vehicles have been assumed to remain stable over the vehicles lifetime. However, there have been hardly any representative long-term emission measurements. Here we present real-driving emissions of diesel cars and light commercial vehicles sampled on-road over 15 years in Zurich/Switzerland. Results suggest deterioration of NOx unit emissions for Euro 2 and Euro 3 diesel technologies, while Euro 1 and Euro 4 technologies seem to be stable. We can exclude a significant influence of high-emitting vehicles. NOx emissions from all cars and light commercial vehicles in European emission inventories increase by 5-10% accounting for the observed deterioration, depending on the country and its share of diesel cars. We suggest monitoring the stability of emission controls particularly for high-mileage light commercial as well as heavy-duty vehicles.

Mode, Load, And Specific Climate Impact from Passenger Trips

The climate impact from a long-distance trip can easily vary by a factor of 10 per passenger depending on mode choice, vehicle efficiency, and occupancy. In this paper we compare the specific climate impact of long-distance car travel with coach, train, or air trips. We account for both, CO2 emissions and short-lived climate forcers. This particularly affects the ranking of aircrafts climate impact relative to other modes. We calculate the specific impact for the Global Warming Potential and the Global Temperature Change Potential, considering time horizons between 20 and 100 years, and compare with results accounting only for CO2 emissions. The cars fuel efficiency and occupancy are central whether the impact from a trip is as high as from air travel or as low as from train travel. These results can be used for carbon-offsetting schemes, mode choice and transportation planning for climate mitigation.

The Evolution and Control of NOx Emissions from Road Transport in Europe

Road transport is the largest contributor to NOx emissions in the EU. This chapter discusses NOx formation mechanisms, control strategies, trends in emissions and possible future developments. Control strategies include vehicle emission legislation, engine design, exhaust after-treatment, modification of fuel properties, alternative fuels and new powertrain technologies. Calculations show that NOx emissions from the sector decreased substantially between 1990 and 2010. Such calculations are based on the assumption that the systematic tightening of emission limits has been effective. However, there is evidence that modern diesel vehicles are not delivering the expected reductions in emissions during real-world driving. Moreover, diesel vehicles emit more NOx than petrol vehicles (with a larger proportion of “primary” NO2), and their market share has increased in many countries. These factors partly explain the observation that ambient NO2 concentrations continue to exceed health-based limits in urban areas. Up to 2020 there is a need for a more effective regulation of emissions, and the chapter proposes several measures that can be taken. Beyond 2020 emissions of NOx from the sector will depend on the market penetration of low-carbon technologies.