Road-traffic emissions of ultrafine particles and elemental black carbon in six Northern European cities

Road-Traffic Emissions of Ultrafine Particles and Elemental Black Carbon in Six Northern European Cities

Abstract. Black carbon (BC) emissions from open biomass burning (BB) are known to have a considerable impact on the radiative budget of the atmosphere at both global and regional scales; however, these emissions are poorly constrained in models by atmospheric observations, especially in remote regions. Here, we investigate the feasibility of constraining BC emissions from BB using satellite observations of the aerosol absorption optical depth (AAOD) and the aerosol extinction optical depth (AOD) retrieved from OMI (Ozone Monitoring Instrument) and MODIS (Moderate Resolution Imaging Spectroradiometer) measurements, respectively. We consider the case of Siberian BB BC emissions, which have the strong potential to impact the Arctic climate system. Using aerosol remote sensing data collected at Siberian sites of the AErosol RObotic NETwork (AERONET) along with the results of the fourth Fire Lab at Missoula Experiment (FLAME-4), we establish an empirical parameterization relating the ratio of the elemental carbon (EC) and organic carbon (OC) contents in BB aerosol to the ratio of AAOD and AOD at the wavelengths of the satellite observations. Applying this parameterization to the BC and OC column amounts simulated using the CHIMERE chemistry transport model, we optimize the parameters of the BB emission model based on MODIS measurements of the fire radiative power (FRP); we then obtain top-down optimized estimates of the total monthly BB BC amounts emitted from intense Siberian fires that occurred from May to September 2012. The top-down estimates are compared to the corresponding values obtained using the Global Fire Emissions Database (GFED4) and the Fire Emission Inventory–northern Eurasia (FEI-NE). Our simulations using the optimized BB aerosol emissions are verified against AAOD and AOD data that were withheld from the estimation procedure. The simulations are further evaluated against in situ EC and OC measurements at the Zotino Tall Tower Observatory (ZOTTO) and also against aircraft aerosol measurement data collected in the framework of the Airborne Extensive Regional Observations in SIBeria (YAK-AEROSIB) experiments. We conclude that our BC and OC emission estimates, considered with their confidence intervals, are consistent with the ensemble of the measurement data analyzed in this study. Siberian fires are found to emit 0.41±0.14 Tg of BC over the whole 5-month period considered; this estimate is a factor of 2 larger and a factor of 1.5 smaller than the corresponding estimates based on the GFED4 (0.20 Tg) and FEI-NE (0.61 Tg) data, respectively. Our estimates of monthly BC emissions are also found to be larger than the BC amounts calculated using the GFED4 data and smaller than those calculated using the FEI-NE data for any of the 5 months. Particularly large positive differences of our monthly BC emission estimates with respect to the GFED4 data are found in May and September. This finding indicates that the GFED4 database is likely to strongly underestimate BC emissions from agricultural burns and grass fires in Siberia. All of these differences have important implications for climate change in the Arctic, as it is found that about a quarter of the huge BB BC mass emitted in Siberia during the fire season of 2012 was transported across the polar circle into the Arctic. Overall, the results of our analysis indicate that a combination of the available satellite observations of AAOD and AOD can provide the necessary constraints on BB BC emissions.

On black carbon emission from automotive disc brakes

The effects of altitude and fuel composition on gaseous and particle emissions from a turbojet engine were investigated as part of the National Jet Fuels Combustion Program (NJFCP) effort. Two conventional petroleum based jet fuels (a “nominal” and a “worst-case” jet fuel) and two test fuels with unique characteristics were selected for this study. The “worst-case” conventional jet fuel with high flash point and viscosity resulted in reduced combustion efficiency supported by the reduced CO2 emissions and corresponding increased CO and THC emissions. In addition, increased particle number (PN), particle mass (PM), and black carbon (BC) emissions were observed. Operating the engine on a bimodal fuel, composed of heavily branched C12 and C16 iso-paraffinic hydrocarbons with an extremely low cetane number did not significantly impact the engine performance or gaseous emissions but significantly reduced PN, PM, and BC emissions when compared to other fuels. The higher aromatic content and lower hydrogen content in the C-5 fuel were observed to increase PN, PM, and BC emissions. It is also evident that the type of aromatic hydrocarbons has a large impact on BC emissions. Reduction in combustion efficiency resulted in reduced CO2 emissions and increased CO and THC emissions from this engine with increasing altitudes. PN emissions were moderately influenced by altitude but PM and BC emissions were significantly reduced with increasing altitude. The reduced BC emissions with increasing altitude could be a result of reduced combustion temperature which lowered the rate of pyrolysis for BC formation, which is supported by the NOx reduction trend.

Atmospheric impacts of black carbon emission reductions through the strategic use of biodiesel in California

Real-time measurements of black carbon and other pollutant emissions from residential biofuel stoves in rural China

PAH, BTEX, carbonyl compound, black-carbon, NO2 and ultrafine particle dynamometer bench emissions for Euro 4 and Euro 5 diesel and gasoline passenger cars

Abstract. Elemental Carbon (EC) has a significant impact on human health and climate change. In order to evaluate the size segregation of EC emission in the EUCAARI inventory and investigate its influence on the simulation of EC long-range transportation in Europe, we used the fully coupled online Weather Research and Forecasting/Chemistry model (WRF-Chem) at a resolution of 2 km focusing on a region in Germany, in conjunction with a high-resolution EC emission inventory. The ground meteorology conditions, vertical structure and wind pattern were well reproduced by the model. The simulations of particle number and/or mass size distributions were evaluated with observations at the central European background site Melpitz. The fine mode particle concentration was reasonably well simulated, but the coarse mode was substantially overestimated by the model mainly due to the plume with high EC concentration in coarse mode emitted by a nearby point source. The comparisons between simulated EC and Multi-angle Absorption Photometers (MAAP) measurements at Melpitz, Leipzig-TROPOS and Bösel indicated that the coarse mode EC (ECc) emitted from the nearby point sources might be overestimated by a factor of 2–10. The fraction of ECc was overestimated in the emission inventory by about 10–30 % for Russia and 5–10 % for Eastern Europe (e.g., Poland and Belarus). This incorrect size-dependent EC emission results in a shorter atmospheric life time of EC particles and inhibits the long-range transport of EC. A case study showed that this effect caused an underestimation of 20–40 % in the EC mass concentration in Germany under eastern wind pattern.

The impacts of black carbon (BC) emissions on climate change, human health, and the environment are well-documented in scientific literature. In response, efforts have been made to reduce BC emissions, particularly in sectors such as energy production, industry, and road transport. However, the maritime shipping industry has largely been exempt from stringent BC emission regulations. While the International Maritime Organization (IMO) has established emission limits for pollutants such as SOx, NOx, and VOCs, as of today, BC emissions from ships are still unregulated at the international level. Whereas the IMO expected that BC emissions would be reduced with the adoption of the SOx regulations, especially within the sulphur emission control areas, this study found that these goals remain largely unmet. This research analyzes real-world BC emissions based on 886 measurements from ships operating in the southern North Sea. Results show that observed BC emission factors (EFs) are significantly higher than previously reported in the literature and those applied by the IMO. In particular, ships equipped with exhaust gas cleaning systems (EGCS) demonstrate increased BC emissions, raising concerns about the environmental benefits of EGCS as a sustainable technology. Non-compliance with sulfur regulations also results in elevated BC emissions, underscoring the need for effective enforcement measures for the existing sulfur emission limits. Furthermore, BC EFs were found to be highly load-dependent, with ships emitting substantially more BC at lower engine loads. This is especially worrying as low engine loads are frequently used in the North Sea for navigation and strategic planning. While slow steaming is increasingly adopted for fuel efficiency at global level. These findings emphasize the significant leverage that the implementation of BC regulations and the development of BC abatement systems could represent for the maritime industry in its ambition to significantly reduce its climate impact.

Adjusting elemental carbon emissions in Northeast Asia using observed surface concentrations of downwind area and simulated contributions

Reducing Black Carbon: A Triple Win for Climate, Health, and Well-Being

The impact of black carbon (BC) emissions on climate change, human health, and the environment is well-documented in the scientific literature. Although BC still remains largely unregulated at the international level, efforts have been made to reduce emissions of BC and Particulate Matter (PM2.5), particularly in sectors such as energy production, industry, and road transport. In contrast, the maritime shipping industry has made limited progress in reducing BC emissions from ships, mainly due to the absence of stringent BC emission regulations. While the International Maritime Organization (IMO) has established emission limits for pollutants such as SOx, NOx, and VOCs under MARPOL Annex VI, as of today, BC emissions from ships are still unregulated at the international level. Whereas it was anticipated that PM2.5 and BC emissions would be reduced with the adoption of the SOx regulations, especially within the sulfur emission control areas (SECA), this study reveals that BC emissions are only partially affected by the current MARPOL Annex VI regulations. Based on 886 real-world black carbon (BC) emission measurements from ships operating in the southern North Sea, the study demonstrates that SECA-compliant fuels do contribute to a notable decrease in BC emissions. However, it is important to note that the average BC emission factors (EFs) within the SECA remain comparable in magnitude to those reported for non-compliant fuels in earlier studies. Moreover, ships using exhaust gas cleaning systems (EGCSs) as a SECA-compliant measure were found to emit significantly higher levels of BC, raising concerns about the environmental sustainability of EGCSs as an emissions mitigation strategy.

Ambient temperature has substantial impacts on vehicle emissions, but the impacts may differ between traditional and alcohol gasolines. The objective of this study was to investigate the effects of temperature on gaseous and particulate emissions with both traditional and alcohol gasoline. Regulated gaseous, particle mass (PM), particle number (PN) and black carbon (BC) emissions from typical passenger vehicles were separately quantified with gasoline, E10 (10% ethanol and 90% gasoline by volume) and M15 (15% methanol and 85% gasoline by volume) at both 30°C and −7°C. The particulate emissions with all fuels increased significantly with decreased temperature. The PM emissions with E10 were only 48.0%–50.7% of those with gasoline at 30°C but increased to 59.2%–79.4% at −7°C. The PM emissions with M15 were comparable to those with gasoline at 30°C, but at −7°C, the average PM emissions were higher than those with gasoline. The variation trend of PN emissions was similar to that of PM emissions with changes in the fuel and temperature. At 30°C, the BC emissions were lower with E10 and M15 than with gasoline in most cases, but E10 and M15 might emit more BC than gasoline at −7°C, especially M15. The results of the transient PN and BC emission rates show that particulate emissions were dominated mainly by those emitted during the cold-start moment. Overall, the particulate emissions with E10 and M15 were more easily affected by ambient temperature, and the advantages of E10 and M15 in controlling particulate emissions declined as the ambient temperature decreased.

Black carbon and organic carbon emissions from wildfires in Mexico

Black carbon (BC) emissions deteriorate air quality in cities and affect human population health. They are important also from climate point of view since atmospheric BC can absorb the solar radiation, affect cloud formation, and decrease ground albedo when deposited to snow or ice. BC is emitted to atmosphere from large variety of different anthropogenic sources. In respect of human exposure to the BC emissions, especially the on-road traffic emissions have had important role, which has led to tightening emission regulations and advanced emission mitigation actions.In this study, we fulfil the data gaps found in recent literature review by new BC emission measurements. Measurements were done for passenger cars, including diesel, diesel-hybrid, gasoline, gasoline-hybrid, and CNG passenger cars, and for two heavy-duty diesel trucks. The measurements with passenger cars were conducted at BOSMAL, Poland, in the laboratory at a chassis dynamometer in a temperature-controlled test cell, where the used driving cycle simulated real driving emissions (RDE). Temperatures in the test cell were -9 °C, 23 °C and 35 °C. The experiments with heavy-duty trucks were conducted on road in Finland in winter-time conditions. In both measurements the exhaust gas was sampled partially and diluted before the characterization with an aethalometer (AE33, Magee). BC measurements were done parallel with large number of other measurements for trace gases and particles.Our preliminary results indicate that the BC emissions of cars varied significantly depending on exhaust aftertreatment systems and driving situations. Very low BC emissions were measured for the cars and heavy-duty trucks with exhaust filtration, and ambient temperature variations had only minor effects on BC emission levels of the studied vehicles.ACKNOWLEDGEMENTS: This work was supported by the European Union’s Horizon Europe research and innovation programme under grant agreement No 101096133 (PAREMPI: Particle emission prevention and impact: from real world emissions of traffic to secondary PM of urban air).