Elevated production of NH 4 NO 3 from the photochemical processing of vehicle exhaust: Implications for air quality in the Seoul Metropolitan Region

Link, Michael F.; Kim, Jounghwa; Park, Gyutae; Lee, Taehyoung; Park, Taehyun; Babar, Zaeem Bin; Sung, Kijae; Kim, Pilho; Kang, Seok‐Won; Kim, Jeong Soo; Choi, Yongjoo; Son, J.; Lim, Ho-Jin; Farmer, Delphine K.

doi:10.1016/j.atmosenv.2017.02.031

Cited by 65 publications

(42 citation statements)

References 54 publications

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“…On the other hand, NH 3 emissions during the urban section were 38 and 32 mg NH 3 /km for GV1 (for the normal and dynamic test respectively) and 11 mg NH 3 /km for GV2. Staying with the results presented by Link et al [28], these NH 3 emissions when reacted with HNO 3 present in the atmosphere would result in approximately 38 mg PM 2.5 /km for GV1 and approximately 11 mg PM 2.5 /km for GV2. It should be noted that tailpipe PM limit for passenger vehicles in the EU is 4.5 mg/km.…”

Section: On-road Emissions From the Gasoline Vehiclessupporting

confidence: 73%

“…Due to the intensive use of the SCR, and the high production of NH 3 , to reduce the NO x emissions, and in absence of an ammonia oxidation catalyst, the DV1 emitted 17 mg NH 3 /km (32 mg NH 3 /km in the urban section). In turn, these NH 3 emissions will potentially react in the atmosphere to produce approximately 17 mg PM 2.5 /km [28].…”

Section: On-road Emissions From the Diesel Vehiclesmentioning

confidence: 99%

“…During this combustion operation NO x and H 2 react and form NH 3 over the TWC increasing the emissions of NH 3 , which is not regulated for light-duty vehicles. As a result, NH 3 is now the dominant reactive nitrogen species emitted by gasoline and LPG vehicles [27,28], including hybrids [29,30]. Moreover, the budget of transport-related NH 3 emissions has been expected to increase as a result of a more intensive use of the SCR systems installed by the most recent diesel vehicles in order to meet the NO x requirements recently introduced with real driving emissions (RDE) procedure [31,32].…”

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confidence: 99%

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Regulated and Non-Regulated Emissions from Euro 6 Diesel, Gasoline and CNG Vehicles under Real-World Driving Conditions

et al. 2020

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The transport sector is one of the main sources air pollutants. Different exhaust after-treatment systems have been implemented over the years to control the emissions of criteria pollutants. However, while reducing the emissions of the target compounds these systems can lead to the emissions of other pollutants and/or greenhouse gases such as NH 3 or N 2 O. Following the implementation of the Real Driving Emissions (RDE) test procedure in the EU, vehicles have been equipped with more complex after-treatment configurations. The impact that these technologies may have on the emissions of non-regulated pollutants during real-world driving have not been evaluated until now. In the current study we present the on-road emissions of a series of non-regulated pollutants, including NH 3 , N 2 O, CH 4 and HCHO, measured with a portable FTIR from a series of Euro 6d, Euro 6c and Euro 6d-TEMP, gasoline diesel and compressed natural gas (CNG) vehicles during real-world testing. The obtained results show that it is possible to measure N 2 O, NH 3 , CH 4 and HCHO during on-road operation. The results also highlight the importance of the measurement of the emissions of these pollutants during real-world driving, as the emissions of NH 3 (a particulate matter precursor) and those of N 2 O and CH 4 (green-house gases) can be high from some vehicle technologies. NH 3 emissions were up to 49 mg/km for gasoline passenger cars, up to 69 mg/km for the CNG light-commercial vehicle and up to 17 mg/km a diesel passenger car equipped with a selective catalytic reduction system (SCR). On the other hand, N 2 O and CH 4 emissions accounted for up to 9.8 g CO 2 eqv/km for a diesel passenger car equipped with a combination of diesel oxidation catalysts (DOC), lean NO x traps (LNT), SCR and possibly an ammonia slip catalyst ASC.Atmosphere 2020, 11, 204 2 of 18 organic compounds (NMVOCs) and CH 4 are the main precursors of ground-level (tropospheric) O 3 . Aiming at improving Europe's air quality, policy actions have increasingly been taken to address transport-related air pollution. At European Union (EU) level, this has included the regulation of emissions by setting emission standards (Euro 1 to Euro 6) or by setting requirements for fuel quality.To meet these standards, passenger cars have been equipped with different emission control systems. Thus, three-way catalytic converters (TWC) are commonly used to reduce the emissions of CO, hydrocarbons (HC) and NO x from gasoline cars. In the case of diesel cars, CO and HC emissions are reduced using diesel oxidation catalysts (DOC), and NO x emissions using selective catalytic reduction systems (SCR), lean NO x traps (LNT) or a combination of both. While reducing the emissions of the target compounds these systems can lead to the emissions of other pollutants that are not currently regulated for the passenger cars in the EU. The emitted pollutants include NH 3 [2,3] and N 2 O. In fact, several laboratory-based studies have indicated that vehicle emissions of NH 3 and N 2 O are linked to the use o...

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Section: On-road Emissions From the Gasoline Vehiclessupporting

confidence: 73%

Section: On-road Emissions From the Diesel Vehiclesmentioning

confidence: 99%

mentioning

confidence: 99%

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Regulated and Non-Regulated Emissions from Euro 6 Diesel, Gasoline and CNG Vehicles under Real-World Driving Conditions

et al. 2020

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“…The fraction of sulfate and nitrate was measured to be 34-49 % in total, with their ratio depending on the case, and the fraction of ammonium varied between 10 and 15 %. Link et al (2017) found that even high NO x emissions can produce negligible amounts of secondary nitrate aerosol if related ammonia emissions are small. Because secondary ammonium nitrate aerosol formation is limited by ammonia, its formation is probably more related to the exhaust after-treatment than the fuel.…”

Section: Instrumentation and Data Analysismentioning

confidence: 99%

Comparison of primary and secondary particle formation from natural gas engine exhaust and of their volatility characteristics

et al. 2017

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Abstract. Natural gas usage in the traffic and energy production sectors is a growing trend worldwide; thus, an assessment of its effects on air quality, human health and climate is required. Engine exhaust is a source of primary particulate emissions and secondary aerosol precursors, which both contribute to air quality and can cause adverse health effects. Technologies, such as cleaner engines or fuels, that produce less primary and secondary aerosols could potentially significantly decrease atmospheric particle concentrations and their adverse effects. In this study, we used a potential aerosol mass (PAM) chamber to investigate the secondary aerosol formation potential of natural gas engine exhaust. The PAM chamber was used with a constant UV-light voltage, which resulted in relatively long equivalent atmospheric ages of 11 days at most. The studied retro-fitted natural gas engine exhaust was observed to form secondary aerosol. The mass of the total aged particles, i.e., particle mass measured downstream of the PAM chamber, was 6-268 times as high as the mass of the emitted primary exhaust particles. The secondary organic aerosol (SOA) formation potential was measured to be 9-20 mg kg −1 fuel . The total aged particles mainly consisted of organic matter, nitrate, sulfate and ammonium, with the fractions depending on exhaust after-treatment and the engine parameters used. Also, the volatility, composition and concentration of the total aged particles were found to depend on the engine operating mode, catalyst temperature and catalyst type. For example, a high catalyst temperature promoted the formation of sulfate particles, whereas a low catalyst temperature promoted nitrate formation. However, in particular, the concentration of nitrate needed a long time to stabilize -more than half an hour -which complicated the conclusions but also indicates the sensitivity of nitrate measurements on experimental parameters such as emission source and system temperatures. Sulfate was measured to have the highest evaporation temperature, and nitrate had the lowest. The evaporation temperature of ammonium depended on the fractions of nitrate and sulfate in the particles. The average volatility of the total aged particles was measured to be lower than that of primary particles, indicating better stability of the aged natural gas engine-emitted aerosol in the atmosphere. According to the results of this study, the exhaust of a natural gas engine equipped with a catalyst forms secondary aerosol when the atmospheric ages in a PAM chamber are several days long. The secondary aerosol matter has different physical characteristics from those of primary particulate emissions.

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“…S3-1 in the Supplement). When corrected for calculated OH suppression, it was 25 % lower than from the SO 2 calibration and was equiv-alent to an integrated OH concentration over 4.6 days at a typical noontime concentration of 1.5 × 10 6 molecules cm −3 (Mao et al, 2010). The OH suppression from VOCs and other OH-reactive gases were calculated using the oxidation chemistry model with 30 s −1 of external OH reactivity, representing rural areas (Feiner et al, 2016;Lee et al, 2009;Peng et al, 2016;Yoshino et al, 2006).…”

Section: Organics-dominatedmentioning

confidence: 99%

Photochemical aging of aerosol particles in different air masses arriving at Baengnyeong Island, Korea

Kang¹,

Lee²,

Brune³

et al. 2018

Atmos. Chem. Phys.

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Abstract. Atmospheric aerosol particles are a serious health risk, especially in regions like East Asia. We investigated the photochemical aging of ambient aerosols using a potential aerosol mass (PAM) reactor at Baengnyeong Island in the Yellow Sea during 4–12 August 2011. The size distributions and chemical compositions of aerosol particles were measured alternately every 6 min from the ambient air or through the highly oxidizing environment of a potential aerosol mass (PAM) reactor. Particle size and chemical composition were measured by using the combination of a scanning mobility particle sizer (SMPS) and a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). Inside the PAM reactor, O3 and OH levels were equivalent to 4.6 days of integrated OH exposure at typical atmospheric conditions. Two types of air masses were distinguished on the basis of the chemical composition and the degree of aging: air transported from China, which was more aged with a higher sulfate concentration and O  :  C ratio, and the air transported across the Korean Peninsula, which was less aged with more organics than sulfate and a lower O  :  C ratio. For both episodes, the particulate sulfate mass concentration increased in the 200–400 nm size range when sampled through the PAM reactor. A decrease in organics was responsible for the loss of mass concentration in 100–200 nm particles when sampled through the PAM reactor for the organics-dominated episode. This loss was especially evident for the m∕z 43 component, which represents less oxidized organics. The m∕z 44 component, which represents further oxidized organics, increased with a shift toward larger sizes for both episodes. It is not possible to quantify the maximum possible organic mass concentration for either episode because only one OH exposure of 4.6 days was used, but it is clear that SO2 was a primary precursor of secondary aerosol in northeast Asia, especially during long-range transport from China. In addition, inorganic nitrate evaporated in the PAM reactor as sulfate was added to the particles. These results suggest that the chemical composition of aerosols and their degree of photochemical aging, particularly for organics, are also crucial in determining aerosol mass concentrations.

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Elevated production of NH 4 NO 3 from the photochemical processing of vehicle exhaust: Implications for air quality in the Seoul Metropolitan Region

Cited by 65 publications

References 54 publications

Regulated and Non-Regulated Emissions from Euro 6 Diesel, Gasoline and CNG Vehicles under Real-World Driving Conditions

Regulated and Non-Regulated Emissions from Euro 6 Diesel, Gasoline and CNG Vehicles under Real-World Driving Conditions

Comparison of primary and secondary particle formation from natural gas engine exhaust and of their volatility characteristics

Photochemical aging of aerosol particles in different air masses arriving at Baengnyeong Island, Korea

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