Volatile Organic Compounds Source Profiles Research Articles

Temperature dependence of source profiles for volatile organic compounds from typical volatile emission sources

Source profiles of volatile organic compounds (VOCs) emitted from the evaporation of various fuels, industrial raw materials, processes and products are still limited in China. The impact of ambient temperature on the VOC released from these fugitive emission sources has also been rarely reported. In order to establish VOC source profiles for thirteen volatile emission sources, a sampling campaign was conducted in Central China, and five types of sources were investigated both in winter and summer. The dominant VOC groups varied in different sources, and they were alkanes (78.6%), alkenes (53.1%), aromatics (55.1%), halohydrocarbons (80.7%) and oxygenated VOCs (OVOCs) (76.0%), respectively. Ambient temperature showed different impacts on VOC source profiles and specific species ratios. The mass percentages of halohydrocarbons emitted from color printing and waste transfer station in summer were 42 times and 20 times higher than those in winter, respectively. The mass percentages of OVOCs emitted from car painting, waste transfer station and laundry emission sources were much higher in summer (7.9–27.8%) than those in winter (0.8–2.6%). On the contrary, alkanes from color printing, car painting and waste transfer stations were about 11, 4 and 5 times higher in winter than those in summer, respectively. The coefficient of divergence values for the source profiles obtained in winter and summer ranged in 0.3–0.7, indicating obvious differences of source profiles. Benzene/toluene ratio varied in 0.00–0.76, and it was in the range of 0.02–0.50 in winter and 0.04–0.52 in summer for the same sources, respectively. Hexanal, isobutene, m,p-xylene, toluene, 2-methylacrolein, styrene, 1-hexane and cis-2-butene dominated the ozone formation potentials (OFP). The OFP summer/winter differences were 5–320 times by MIR method and 1–79 times by Propy-Equiv method, respectively. This study firstly gave direct evidence that ambient temperature modified the mass percentages of VOC species obviously. It is important for improving VOC source apportionment and chemical reactivity simulation.

Profile Characteristics of VOCs from Wood and Economic Crop Burning

Wood and economic crops are still widely used in rural areas of China. Although their combustion is an important source of volatile organic compounds (VOCs), study on their emission characteristics is relatively weak. In this study, three kinds of wood (poplar, cedarwood, and citrus branches) and six economic crop straws (soybean stalk, sesame stalk, corn cob, cotton stalk, peanut stalk, and corn stalk) were selected and their burning was simulated in the laboratory. A dilution tunnel system was used to dilute the smoke, and then Tedlar bags were used to collect the smoke. The compositions of 102 VOCs were analyzed by Agilent 7820A/5977E gas chromatography/mass spectrometry. The ozone formation potential (OFP) of VOCs for different types of biomass burning was analyzed. The results indicated that there are differences in the VOC compositions of different types of biomass burning emissions. Ethane (11.1%), trans-2-pentene (15.4%), ethylene (8.3%), and dichloromethane (11.9%) are the main VOCs emitted from poplar and cedarwood burning. Toluene (49.8%) is the most abundant species of VOC emitted from burning of citrus branches. Ethylene (11.8%-17.5%) and acetone (9.2%-14.7%) are the main VOCs components of straw burning. Corn stalks, peanut stalks, and citrus branches have similar VOC source profiles, with the coefficient of divergence less than 0.1. The benzene/toluene ratio for biomass burning emissions obtained in this study and in the literature is in the range of 0.030-6.48. It is arguable that a value higher than 1 indicated the impact of biomass burning. The contributions of alkenens, oxygenated VOCs, and aromatic hydrocarbons to the OFP of biomass burning were 30.6%-80.3%, 6.5%-21.0%, and 3.8%-56.5%, respectively. The components contributing more than 10.0% to the OFP are ethylene, propylene, trans-2-pentene, cis-2-pentene, toluene, and propionaldehyde.

Typical industrial sector-based volatile organic compounds source profiles and ozone formation potentials in Zhengzhou, China

Volatile organic compounds (VOCs) emitted from local industries can cause PM2.5 and ozone pollution. The VOCs source profiles of 14 industries were set up on the basis of on-site sampling in this work. The sectors were divided into four following groups according to their largest fraction of emission component: oxygenated VOCs (OVOCs), aromatic, alkane, and halohydrocarbon emissions. The main species for OVOCs, alkane, and halohydrocarbon emissions were ethanol and ethyl acetate, C5–C12 substances, and 1,2-dichloroethane and trichloromethane, respectively. In terms of aromatic emissions, complex and various species were emitted. A comparison of the automobile and furniture manufacturing sectors with other regions indicated that some similarities exist in aromatic emissions. However, Zhengzhou City had a remarkably lower toluene emission than do other areas, and some special species were also detected in the locality. The ozone formation potential (OFP) profiles were also set up through the VOCs source profiles and maximum incremental reactivity (MIR) theory, which illustrated that the automobile manufacturing sector had the largest influence on ozone formation owing to increased furniture manufacturing (3.41), followed by aromatic emissions (2.94). Aromatics and OVOCs from similar sources had a significant effect on the OFP values. In general, the main influential species in Zhengzhou are ethanol, 2-hexanone, 1,2,3-trimethylbenzene, 1,2,4-trimethylbenze, m/p-xylene, o-xylene, and toluene for VOCs and ozone pollution.

Speciated VOCs Emission Inventory and Ozone Formation Potential in Sichuan Province

Based on the measured data in the literature, VOCs (volatile organic compounds) source profiles were revised and reconstructed without OVOCs (oxygenated volatile organic compounds) species to obtain the normalized VOCs source profiles. Using the 2015 Sichuan emission inventory, source profiles based on the 1 km×1 km gridded speciated VOCs emission inventory were developed, and the ozone formation potentials of the species were estimated to assess the environmental impact on ozone formation. The established VOCs source profile database consists of 45 source profiles and 519 species. Since the source profiles were established based on the revision and reconstruction of pollution sources, such as biomass burning and transportation, that are rich in OVOCs, the source profile database is better applicable to establishing the speciated VOCs emission inventory and source apportionment. The speciated VOCs emission inventory showed that the total anthropogenic emission of VOCs in Sichuan Province was 773.8 kt, of which the emissions of alkanes, olefins, alkynes, aromatics, OVOCs, halohydrocarbons, and other VOCs accounted for 21.6%, 10.0%, 1.7%, 28.0%, 26.2%, 4.2%, and 8.3% of the total respectively. The total OFP (Ozone formation potential) was 2584.9 kt, of which the OFPs of the VOCs groups mentioned above accounted for 6.9%, 26.1%, 0.5%, 42.3%, 23.2%, 0.4%, and 0.5% respectively. The main VOCs species emitted in all cities of Sichuan Province were aromatics, OVOCs, and alkanes; however, there were some significant regional differences:transportation in Chengdu, Ya'an, Aba, Ganzi, and Liangshan made a greater contribution to VOCs emissions, with alkane emissions accounting for a higher proportion in the total VOCs emission. As a heavy industrial city, Panzhihua suffered most from emissions from industrial processes, which contain a relatively high proportion of alkanes. Solvent use in Deyang, Meishan, Suining, and Ziyang made a great contribution to the VOCs emissions, and the OVOCs emission was relatively high. Emissions of VOCs and species with relatively high OFPs in Sichuan Province were mainly distributed in the Sichuan Basin, which has a dense population and highly developed industry, as well as some areas in Liangshan and Panzhihua. The main source of m-xylene and toluene was solvent use; therefore, m-xylene and toluene were relatively concentrated in developed urban areas. In addition, biomass burning contributed greatly to the emissions of ethene and formaldehyde; therefore, ethene and formaldehyde were mainly distributed in the cultivated areas of agriculturally advanced Eastern Sichuan and Southern Sichuan.

Volatile Organic Compounds Emission from Chinese Wood Furniture Coating Industry: Activity-based Emission Factor, Speciation Profiles, and Provincial Emission Inventory

Volatile organic compounds (VOCs) have been identified as the most crucial precursors of tropospheric photochemical O3 formation and secondary organic aerosols. In this study, field measurement was conducted to develop VOCs emission factors and source profiles of the wood furniture coating industry in China. An activity-based database was established, involving coat consumption-based, coating area-based, furniture production-based, and output value-based VOCs emission factors. Combining the results of field tests and literature surveys, emission factors were calculated by enterprise scale, coating type, spraying technology, and emission control device. The uncertainties were quantified by using Monte Carlo simulations. VOCs emission factors were estimated: 0.22 (0.10–0.34, 95% CI) kg kg–1 for coat consumption-based; 21.97 (10.10–29.38) g m–2 for coating area–based; 0.69 (0.34–1.00) kg piece–1 for furniture production-based; and 6.95 (3.42–10.21) kg 10–4 yuan for output value–based calculation, respectively. Aromatics and oxygenated VOCs (OVOCs) were predominant species of solvent borne paint emission, with the proportion of 71.1% and 22.9% of totals, respectively. VOCs emissions from the wood furniture coating industry were estimated at 179.76 × 103 (88.58 × 103–260.52 × 103, 95% CI) t in 2016. Due to the huge production output and intensive distribution of enterprises, VOCs emissions mainly concentrated in Guangdong, Zhejiang, Shandong, Fujian, Jiangxi, and Sichuan province, with the combined contribution of 43.8% of the national totals.

Volatile organic compounds (VOCs) source profiles of on-road vehicle emissions in China

Volatile Organic Compounds (VOCs) source profiles of on-road vehicles were widely studied as their critical roles in VOCs source apportionment and abatement measures in megacities. Studies of VOCs source profiles from on-road motor vehicles from 2001 to 2016 were summarized in this study, with a focus on the comparisons among different studies and the potential impact of different factors. Generally, non-methane hydrocarbons dominated the source profile of on-road vehicle emissions. Carbonyls, potential important components of vehicle emission, were seldom considered in VOCs emissions of vehicles in the past and should be paid more attention to in further study. VOCs source profiles showed some variations among different studies, and 6 factors were extracted and studied due to their impact to VOCs source profile of on-road vehicles. Vehicle types, being dependent on engine types, and fuel types were two dominant factors impacting VOCs sources profiles of vehicles. In comparison, impacts of ignitions, driving conditions and accumulated mileage were mainly due to their influence on the combustion efficiency. An opening and interactive database of VOCs from vehicle emissions was critically essential in future, and mechanisms of sharing and inputting relative research results should be formed to encourage researchers join the database establishment. Correspondingly, detailed quality assurance and quality control procedures were also very important, which included the information of test vehicles and test methods as detailed as possible. Based on the community above, a better uncertainty analysis could be carried out for the VOCs emissions profiles, which was critically important to understand the VOCs emission characteristics of the vehicle emissions.

Volatile Organic Compounds(VOCs) Source Profiles of Industrial Processing and Solvent Use Emissions: A Review

Industrial processing and solvent use are two most important industrial sources of volatile organic compounds (VOCs) in China, and the source profile study has attracted increasing attention recently. Studies of VOCs source profiles from industrial processing and solvent use since the year of 2000 were summarized in this study, focusing on the comparison among different studies and the potential impact of different research methods. In general, studies were very limited and focused on few sources. Specifically, only 8 of 32 sub-categories of the industrial processing (according to the source classification method of the National Guidelines for VOCs Inventories Preparation) have been reported, and in terms of the solvent use sources, 4 of 10 sub-categories have been reported. There were large differences among the VOCs patterns of different sub categories emissions of industrial processing or solvent use. In terms of studies of the similar emissions, significant differences of VOCs profiles were resulted from the different research methods, such as the different sampling methods and VOCs analysis techniques. In addition, the non-uniformity of VOC species in the source profile caused difficulty for the comparison of different research results. Oxygen-containing VOCs were important components of the above two types of pollution sources and needed to be included in the measurement. An opening and interactive database of VOCs from industrial processing and solvent use is critically essential in the future, and mechanisms of sharing and inputting relative research results should be formed to encourage researchers to join the database establishment. Correspondingly, detailed quality assurance and quality control procedures are also very important, which include the detailed information such as research objectives, sampling and analysis methods, research region and time, and test times, et al. Based on the community above, a better uncertainty analysis could be carried out for the VOCs emissions profiles, which is critically important to understand the VOCs emission characteristics of the industrial processing and solvent use.

Reactivity-based Anthropogenic VOCs Emission Inventory in China

A reactivity-based anthropogenic volatile organic compounds (VOCs) emission inventory in China in 2010 was developed on the basis of ozone formation potential (OFP), using the latest VOCs emission inventory, source profiles and maximum incremental reactivity (MIR) values. The results showed that the total anthropogenic OFP was 84187.61 kt in China in 2010, of which 6882.53 kt was from alkanes, 41496.92 kt from alkenes/alkynes, 32945.32 kt from aromatic hydrocarbons, 161.45 kt from halocarbons, and 2701.40 kt from oxygenated organics. The top 10 species in terms of OFP consisted of propene, ethene, m/p-xylene, toluene, 1-butene, o-xylene, 1,2,4-trimethyl benzene, 1,3-butadiene, m-ethyl toluene and ethyl benzene, contributing 63.95% to the total OFP but only 31.84% to the mass-based emission. Industrial sources accounted for the largest (49.29%) of the total OFP, followed by transportation sources (28.31%) and agricultural sources (22.40%). The key industrial sources with high reactivity were architectural decoration industry, oil refinery industry, storage and transport, machinery equipment industry, transport equipment industry and printing. Passenger cars, motorcycles and heavy duty vehicles were the major OFP sources of transportation. The two biomass burning sources were both the key OFP sources of agriculture. Shandong, Jiangsu, Guangdong, Zhejiang and Henan were the top five provinces with contributions of 39.65% of the total OFP in China. The reactivity-based emission inventory in this study would be of great significance for the formulation of reactivity-based ozone (O3) control strategies in China.

Source Profile of Volatile Organic Compounds (VOCs) of a Petrochemical Industry in the Yangtze River Delta, China

The profiles of major volatile organic compound (VOC) sources in petrochemical industry of the Yangtze river delta, China, were experimentally determined. Source samples were taken using summa canister near the petrochemical units. The concentrations of 72 VOC species were quantified using canister sampling and a gas chromatography–mass spectrometry system, and VOC source profiles were developed for source apportionment of VOCs. Based on the measurement of source profiles, possible tracers for various emission sources were identified; The VOCs emitted from the whole refinery were characteristic by aromatic (43.2%), alkane (27.7%), halonhydrocarbon (21.2%) and oxygenated VOCs(7.3%). And the obvious differences in VOCs chemical profiles among four main sectors (Petroleum refining, Olefin refining, Aromatic refining and Wastewater treatment sectors). Petroleum refining with the higher proportions of C3-C10 alkanes, Olefin refining with the higher proportions of BTX(benzene, toluene, m,p-xylene). and C2-C4 alkenes. Aromatic refining with the higher proportions of BTX(benzene, toluene, m,p-xylene), wastewater treatment with the higher proportions of BTX (benzene, toluene, m,p-xylene), and part halonhydrocarbon and oxygenated VOCs were also its characteristic compounds .

Source apportionment of VOCs in a suburb of Nanjing, China, in autumn and winter

Volatile organic compounds (VOCs) were measured in a suburb of Nanjing by on-line gas chromatography-flame ionization detector (GC-FID) instruments from September 2011 to January 2012. The measured VOC concentrations are dominated by alkanes (47 %), alkenes (25 %) and aromatics (20 %); in which alkenes attributed 57 % to the propylene-equivalent concentrations and 58 % to the ozone formation potential. The benzene to toluene (B/T) ratio was 1.60 ± 1.28, larger than 1, suggesting that the combustion sources might be significant at this site. Based on the measured VOC concentrations, a receptor model (PCA/APCS; principal component analysis/absolute principal component scores) coupled with the measured VOC source profiles was applied to identify the major VOC sources. Five surrogated VOC sources were identified: fossil-fuel/biomass/biofuel combustion accounted for 28 % of the total VOC concentrations, followed by the combination of solvent usage and industrial sources 1 (26 %), fuel evaporations (23 %), vehicular exhaust (18 %) and industrial sources 2 (5 %). Furthermore, the method was applied to analyze VOC sources in four quadrants (northeast, northwest, southeast and southwest) based on wind directions. Industrial sources were the most significant contributors (33 %) in the NE quadrant; VOCs in the NW quadrant were mainly contributed by the combination of fuel evaporation and fossil fuel/biomass/biofuel combustion (50 %). The most important source in the SE quadrant was the combination of solvent usage and industrial sources 1 (35 %), while 51 % of VOC concentrations were attributed to fossil fuel/biomass/biofuel combustion in the SW quadrant, indicating that the source contributions in various quadrants were quite different. This study may provide useful information for establishing effective air pollution control strategies in this region.

Source Profiles and Chemical Reactivity of Volatile Organic Compounds from Solvent Use in Shanghai, China

Chamber experiments, exhaust collection, and in-situ sampling were employed to study the emission profiles of volatile organic compounds (VOCs) from solvent use, specifically indoor paint, auto paint, furniture paint, and print ink, which are of significant importance with regard to VOC emissions in Shanghai. The results showed that there were some differences among these VOC source profiles of the emissions associated with different solvents. On the one hand, for emissions from imported indoor solvents, ~50% of the total mass concentration was contributed by aromatics, and ~30% by alkanes. On the other hand, VOC source profiles from domestic indoor paint, furniture paint, and auto paint were similar in the sense that aromatics made a much larger contribution to total VOCs, specifically, 98% for domestic indoor paint, 80%–93% for the other two, and C8–C9 aromatics accounted for ~70% of total VOCs. For VOCs from printing, C2–C5 species dominated by more than 50%, followed by C8–C9 aromatics. VOCs from the use of different solvents presented different chemical reactivities. Among the four solvents listed above, the average OH loss rate constant (k-avg) and maximum incremental reactivity (MIR-avg) of VOCs from printing were the lowest, with values of 8.2 × 10 –12 cm 3 /molecule/s and 2.9 g(O3)/g(VOC), respectively. For VOCs from painting, the average reactivity was twice that of VOCs from printing, and its value of MIR-avg was 4.7–6.3 g(O3)/g(VOC). There are significant variations in the VOC source profiles related to solvent use in different studies. The representativeness of the solvents studied and the VOC samples collected should thus be more closely examined. The accuracy of VOC source profiles related to solvent use is highly dependent on location and sampling frequency.

Speciated VOC Emission Inventory and Spatial Patterns of Ozone Formation Potential in the Pearl River Delta, China

The Pearl River Delta region (PRD) of China has long suffered from severe ground-level ozone pollution. Knowledge of the sources of volatile organic compounds (VOCs) is essential for ozone chemistry. In this work, a speciated VOC emission inventory was established on the basis of updated emissions and local VOC source profiles. The top 10 species, in terms of ozone formation potentials (OFPs), consisted of isoprene, mp-xylene, toluene, ethylene, propene, o-xylene, 1,2,4-trimethylbenzene, 2-methyl-2-butene, 1-butene, and alpha-pinene. These species contributed only 35.9% to VOCs emissions but accounted for 64.1% of the OFP in the region. The spatial patterns of the VOC source inventory agreed well with city-based source apportionment results, especially for vehicle emissions and industry plus VOC product-related emissions. Mapping of the OFPs and measured ozone concentrations indicated that the formation of higher ozone in the south and southeast of the PRD region differed from that in the Conghua area, a remote area in the north of the PRD. We recommend that the priorities for the control of VOC sources include motorcycles, gasoline vehicles, and solvent use because of their larger OFP contributions.

Source profiles of volatile organic compounds (VOCs) measured in China: Part I

The profiles of major volatile organic compound (VOC) sources in China, including vehicle exhaust, gasoline vapor, paint, asphalt, industrial and residential coal burning, biomass burning, and the petrochemical industry, were experimentally determined. Source samples were taken using a dilution chamber for mobile and stationary sources, biomass burning in an actual Chinese farmer's house, and ambient air in a petrochemical industrial area. The concentrations of 92 VOC species were quantified using canister sampling and a gas chromatography–flame ionization detection/mass spectrometry system, and VOC source profiles were developed for source apportionment of VOCs in the Pearl River Delta region. Based on the measurement of source profiles, possible tracers for various emission sources were identified; e.g., 2-methylpentane and 1,3-butadiene could be used as tracers for vehicle exhaust; the characteristic compounds of architectural coating were aromatics such as toluene and m, p-xylene; the light hydrocarbons, namely n-butane, trans-2-butene, and n-pentane, dominated the composition of gasoline vapor; and n-nonane, n-decane, and n-undecane were found to be typical of diesel vapor and asphalt application processes. As different emission sources are characterized by overlapping VOC species, the ratio of possible VOC tracers could be used to assess the contribution of various sources. The ratios between n-butane and isobutane, 1,3-butadiene and isoprene, and the ratios of aromatics (e.g., toluene to benzene and ethylbenzene to m, p-xylene) in the measured sources were compared.