scholarly journals Vehicular volatile organic compounds (VOCs)-NO<sub><i>x</i></sub>-CO emissions in a tunnel study in northern China: emission factors, profiles, and source apportionment

2018 ◽  
Author(s):  
Congbo Song ◽  
Yan Liu ◽  
Shida Sun ◽  
Luna Sun ◽  
Yanjie Zhang ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Emission Inventory ◽  
Northern China ◽  
Emission Factors ◽  
Voc Emissions ◽  
Evaporative Emissions ◽  
Emission Standards ◽  
Volatile Organic ◽  
Vehicular Exhaust

Abstract. Vehicular emission is a key contributor to ambient volatile organic compounds (VOCs) and NOx in Chinese megacities. However, the information of real-world emission factors (EFs) for a typical urban fleet is still limited, hindering the development of a more reliable emission inventory in China. Based on a more-than-two-week (August 8–24, 2017) tunnel test in urban Tianjin in northern China, and on the use of a statistical regression model, the Positive Matrix Factorization (PMF) receptor model, and the Calculate Emissions from Road Transport (COPERT) IV model, characteristics of vehicular VOCs-NOx-CO emissions were analyzed systematically. The fleet-average EFs (pollutant: downslope, upslope, and overall in mg km−1 veh−1) were estimated respectively as follows: (NO: 61.92 ± 72.46, 158.58 ± 73.48, 97.52 ± 69.84), (NO2: 16.52 ± 11.49, 23.98 ± 20.14, 15.86 ± 9.38), (NOx: 79.45 ± 78.43, 181.22 ± 88.29, 116.56 ± 77.61), and (CO: 269.96 ± 342.38, 577.76 ± 382.22, 344.67 ± 250.01). The EFs of NO-NO2-NOx and CO from heavy-duty vehicles (or diesel vehicles) were differentiated from light-duty vehicles (or gasoline vehicles). The ratios (v / v) of NO2 to NOx in the primary vehicular exhaust were approximately 0.18 ± 0.09, 0.10 ± 0.22 and 0.10 ± 0.05 for downslope, upslope, and the entire tunnel, respectively. The fleet-average EF of the 99-target non-methane VOCs (NMVOCs) was 40.56 ± 12.18 mg km−1 veh−1, lower than the previous studies in China. The BTEX (benzene, toluene, ethylbenzene, p-xylene, m-xylene and o-xylene) levels decreased by approximately 79 % when emission standards increased from China I to China V. The source profiles of NMVOCs from the tailpipe and evaporative emissions were resolved by the PMF model. The evaporative emissions accounted for nearly one-half of the total vehicular VOC emissions, indicating that evaporative and tailpipe emissions contributed equally to VOC emissions. The relative contributions of evaporative NMVOC emissions to total vehicular NMVOC emissions are temperature-dependent with the average increasing ratio of 7.55 % °C−1. The primary emission ratio (ER, m / m) of VOCs / NOx was approximately 2.04, suggesting that vehicular NOx and VOCs can be co-emitted with a proper ER. According to the vehicular ERs of VOCs / NOx in Tianjin (2000–2016) and China (2010–2030), as even more stringent emission standards are implemented in the future, the O3 chemical regimes were likely to be VOCs-limited (i.e., 8 : 1 threshold) for cities or regions where VOCs and NOx emissions are dominated by vehicular exhaust. Our study enriched the database on the fleet-average emission factors of on-road vehicles for emission inventory, air quality modeling, and health effects studies, provided implications for following O3 control in China from the view of primary emission, and highlighted the importance of further control of evaporative emissions.

scholarly journals Surface–atmosphere fluxes of volatile organic compounds in Beijing

2020 ◽  
Vol 20 (23) ◽  
pp. 15101-15125
Author(s):  
W. Joe F. Acton ◽  
Zhonghui Huang ◽  
Brian Davison ◽  
Will S. Drysdale ◽  
Pingqing Fu ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Emission Inventory ◽  
Central Area ◽  
High Reactivity ◽  
Emission Rates ◽  
Voc Emissions ◽  
Formation Potential ◽  
Surface Atmosphere ◽  
Volatile Organic

Abstract. Mixing ratios of volatile organic compounds (VOCs) were recorded in two field campaigns in central Beijing as part of the Air Pollution and Human Health in a Chinese Megacity (APHH) project. These data were used to calculate, for the first time in Beijing, the surface–atmosphere fluxes of VOCs using eddy covariance, giving a top-down estimation of VOC emissions from a central area of the city. The results were then used to evaluate the accuracy of the Multi-resolution Emission Inventory for China (MEIC). The APHH winter and summer campaigns took place in November and December 2016 and May and June 2017, respectively. The largest VOC fluxes observed were of small oxygenated compounds such as methanol, ethanol + formic acid and acetaldehyde, with average emission rates of 8.31 ± 8.5, 3.97 ± 3.9 and 1.83 ± 2.0 nmol m−2 s−1, respectively, in the summer. A large flux of isoprene was observed in the summer, with an average emission rate of 5.31 ± 7.7 nmol m−2 s−1. While oxygenated VOCs made up 60 % of the molar VOC flux measured, when fluxes were scaled by ozone formation potential and peroxyacyl nitrate (PAN) formation potential the high reactivity of isoprene and monoterpenes meant that these species represented 30 % and 28 % of the flux contribution to ozone and PAN formation potential, respectively. Comparison of measured fluxes with the emission inventory showed that the inventory failed to capture the magnitude of VOC emissions at the local scale.

scholarly journals VOC emissions, evolutions and contributions to SOA formation at a receptor site in Eastern China

2013 ◽  
Vol 13 (3) ◽  
pp. 6631-6679 ◽  
Author(s):  
B. Yuan ◽  
W. W. Hu ◽  
M. Shao ◽  
M. Wang ◽  
W T.. Chen ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Emission Inventory ◽  
Eastern China ◽  
Receptor Site ◽  
Voc Emissions ◽  
Parameterization Method ◽  
Voc Oxidation ◽  
Volatile Organic ◽  
Emission Ratios

Abstract. Volatile organic compounds (VOCs) were measured by two online instruments (GC-FID/MS and PTR-MS) at a receptor site on Changdao Island (37.99° N, 120.70° E) in eastern China. Reaction with OH radical dominated the chemical loss of most VOC species during the Changdao campaign. A photochemical age based parameterization method is used to calculate VOC emission ratios and to quantify the evolution of ambient VOCs. The calculated emission ratios of most hydrocarbons agree well with those obtained from emission inventory, but the emission ratios of oxygenated VOCs (OVOCs) are significantly lower than those from emission inventory. The photochemical age based parameterization method is also used to investigate primary emissions and secondary formation of organic aerosol. The primary emission ratio of OA to CO are determined to be 14.9 μg m−3 ppm−1 and SOA are produced at an enhancement ratio of 18.8 μg m−3 ppm−1 to CO after 50 h of photochemical processing in the atmosphere. SOA formation is significantly higher than the level determined from VOC oxidation under both high-NOx (2.0 μg m−3 ppm−1 CO) and low-NOx condition (6.5 μg m−3 ppm−1 CO). Polycyclic aromatic hydrocarbons (PAHs) and higher alkanes (>C10) account for as high as 17.4% of SOA formation, which suggests semi-volatile organic compounds (SVOCs) may be a large contributor to SOA formation during the Changdao campaign. SOA formation potential of primary VOC emissions determined from both field campaigns and emission inventory in China are lower than the measured SOA levels reported in Beijing and Pearl River Delta (PRD), indicating SOA formation cannot be explained by VOC oxidation in this regions. SOA budget in China is estimated to be 5.0–13.7 Tg yr−1, with a fraction of at least 2.7 Tg yr−1 from anthropogenic emissions, which are much higher than the previous estimates from regional models.

scholarly journals Species and characteristics of volatile organic compounds emitted from an auto-repair painting workshop

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. Y. Song ◽  
H. Chun
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Large Scale ◽  
Butyl Acetate ◽  
Small Scale ◽  
Indoor Environments ◽  
Voc Emissions ◽  
Volatile Organic ◽  
Before And After ◽  
Adsorption Systems

AbstractVolatile organic compounds (VOCs) are secondary pollutant precursors having adverse impacts on the environment and human health. Although VOC emissions, their sources, and impacts have been investigated, the focus has been on large-scale industrial sources or indoor environments; studies on relatively small-scale enterprises (e.g., auto-repair workshops) are lacking. Here, we performed field VOC measurements for an auto-repair painting facility in Korea and analyzed the characteristics of VOCs emitted from the main painting workshop (top coat). The total VOC concentration was 5069–8058 ppb, and 24–35 species were detected. The VOCs were mainly identified as butyl acetate, toluene, ethylbenzene, and xylene compounds. VOC characteristics differed depending on the paint type. Butyl acetate had the highest concentration in both water- and oil-based paints; however, its concentration and proportion were higher in the former (3256 ppb, 65.5%) than in the latter (2449 ppb, 31.1%). Comparing VOC concentration before and after passing through adsorption systems, concentrations of most VOCs were lower at the outlets than the inlets of the adsorption systems, but were found to be high at the outlets in some workshops. These results provide a theoretical basis for developing effective VOC control systems and managing VOC emissions from auto-repair painting workshops.

scholarly journals Water-Enhanced Flux Changes under Dynamic Temperatures in the Vertical Vapor-Phase Diffusive Transport of Volatile Organic Compounds in Near-Surface Soil Environments

2021 ◽  
Vol 13 (12) ◽  
pp. 6570
Author(s):  
Asma Akter Parlin ◽  
Monami Kondo ◽  
Noriaki Watanabe ◽  
Kengo Nakamura ◽  
Mizuki Yamada ◽  
...  
Keyword(s):  
Air Quality ◽  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Vapor Phase ◽  
Inverse Correlation ◽  
Diffusive Transport ◽  
Near Surface ◽  
Voc Emissions ◽  
Transport Behavior ◽  
Volatile Organic

The quantitative understanding of the transport behavior of volatile organic compounds (VOCs) in near-surface soils is highly important in light of the potential impacts of soil VOC emissions on the air quality and climate. Previous studies have suggested that temperature changes affect the transport behavior; however, the effects are not well understood. Indeed, much larger changes in the VOC flux under in situ dynamic temperatures than those expected from the temperature dependence of the diffusion coefficients of VOCs in the air have been suggested but rarely investigated experimentally. Here, we present the results of a set of experiments on the upward vertical vapor-phase diffusive transport of benzene and trichloroethylene (TCE) in sandy soils with water contents ranging from an air-dried value to 10 wt% during sinusoidal temperature variation between 20 and 30 °C. In all experiments, the flux from the soil surface was correlated with the temperature, as expected. However, the changes in flux under wet conditions were unexpectedly large and increased with increasing water content; they were also larger for TCE, the volatility of which depended more strongly on the temperature. Additionally, the larger flux changes were accompanied by a recently discovered water-induced inverse correlation between temperature and flux into the overlying soil. These results demonstrated that the flux changes of VOCs under dynamic temperatures could be increased by volatilization-dissolution interactions of VOCs with water. Future extensive studies on this newly discovered phenomenon would contribute to a better understanding of the impacts of soil VOC emissions on the air quality and climate.

Volatile organic compounds sources in Paris in spring 2007. Part II: source apportionment using positive matrix factorisation

2011 ◽  
Vol 8 (1) ◽  
pp. 91 ◽  
Author(s):  
Cécile Gaimoz ◽  
Stéphane Sauvage ◽  
Valérie Gros ◽  
Frank Herrmann ◽  
Jonathan Williams ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compound ◽  
Organic Compounds ◽  
Emission Inventory ◽  
Positive Matrix ◽  
Air Mass ◽  
Volatile Organic ◽  
Industrial Sources ◽  
Fuel Evaporation ◽  
Matrix Factorisation

Environmental context Volatile organic compounds are key compounds in atmospheric chemistry as precursors of ozone and secondary organic aerosols. To determine their impact at a megacity scale, a first important step is to characterise their sources. We present an estimate of volatile organic compound sources in Paris based on a combination of measurements and model results. The data suggest that the current emission inventory strongly overestimates the volatile organic compounds emitted from solvent industries, and thus needs to be corrected. Abstract A positive matrix factorisation model has been used for the determination of volatile organic compound (VOC) source contributions in Paris during an intensive campaign (May–June 2007). The major sources were traffic-related emissions (vehicle exhaust, 22% of the total mixing ratio of the measured VOCs, and fuel evaporation, 17%), with the remaining emissions from remote industrial sources (35%), natural gas and background (13%), local sources (7%), biogenic and fuel evaporation (5%) and wood-burning (2%). It was noted that the remote industrial contribution was highly dependent on the air-mass origin. During the period of oceanic influences (when only local and regional pollution was observed), this source made a relatively low contribution (<15%), whereas the source contribution linked to traffic was high (54%). During the period of continental influences (when additional continental pollution was observed), remote industrial sources played a dominant role, contributing up to 50% of measured VOCs. Finally, the positive matrix factorisation results obtained during the oceanic air mass-influenced period were compared with the local emission inventory. This comparison suggests that the VOC emission from solvent industries might be overestimated in the inventory, consistent with findings in other European cities.

scholarly journals Emissions of volatile organic compounds from crude oil processing – Global emission inventory and environmental release

2020 ◽  
Vol 727 ◽  
pp. 138654 ◽  
Author(s):  
Hamid Rajabi ◽  
Mojgan Hadi Mosleh ◽  
Parthasarathi Mandal ◽  
Amanda Lea-Langton ◽  
Majid Sedighi
Keyword(s):  
Volatile Organic Compounds ◽  
Crude Oil ◽  
Organic Compounds ◽  
Emission Inventory ◽  
Oil Processing ◽  
Global Emission ◽  
Volatile Organic
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