Volatile Organic Compounds Source Profiles Research Articles

Emission factors and source profiles of volatile organic compounds from the automobile manufacturing industry

Controlling volatile organic compounds (VOCs) emitted from the automobile manufacturing industry requires establishing VOCs emission factors (EFs) and source profiles refinedly. In this study, 41 samples involved 32 VOCs discharge links were collected from three factories. The EFs and VOCs source profiles were estimated by the material balance method and weighted average method, respectively. The ozone formation potential (OFP) of the 110 VOCs species were calculated by the maximum incremental reactivity (MIR). According to estimations, the ranges of EFs were 0.23–1.66 kg VOCs/SUV car and 2.14–14.86 g VOCs/m2 painted area. EFs of six materials were firstly estimated, which are electrophoretic primer (152.31 ± 97.39 g VOCs/SUV car, 0.97 ± 0.38 g VOCs/m2 painted area), sealant (48.39 ± 26.20 g VOCs/SUV car, 0.46 ± 0.25 g VOCs/m2 painted area), floating coat (87.40 ± 75.63 g VOCs/SUV car, 0.86 ± 0.74 g VOCs/m2 painted area), colored paint (127.24 ± 168.24 g VOCs/SUV car, 1.25 ± 1.66 g VOCs/m2 painted area), varnish (205.46 ± 218.14 g VOCs/SUV car, 2.01 ± 2.15 g VOCs/m2 painted area), and cleaning solvent (328.54 ± 404.94 g VOCs/SUV car, 3.23 ± 3.98 g VOCs/m2 painted area). OVOCs (37.40–51.60 %) and aromatics (36.40–37.00 %) were the dominant components. n-Butyl acetate, 1,2,4-trimethylbenzene, undecane, n-hexanal, acetone, 1,2,3-trimethylbenzene, 1,3,5 -trimethylbenzene, m/p/o-xylene, 3-ethylbenzene, and 4-ethylbenzene were the major VOCs species, accounting for 68 % of total VOCs in the automobile manufacturing industry. Considering the OFP values of species, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene, 1,2,3-trimethylbenzene, m/p-xylene, acetaldehyde, methyl ethyl ketone are the key active species that should be prioritized for control.

Characteristics of Volatile Organic Compounds Emitted from Airport Sources and Their Effects on Ozone Production.

In recent years, commercial air transport has increased considerably. However, the compositions and source profiles of volatile organic compounds (VOCs) emitted from aircraft are still not clear. In this study, the characteristics of VOCs (including oxygenated VOCs (OVOCs)) emitted from airport sources were measured at Shenzhen Bao'an International Airport. The results showed that the compositions and proportions of VOC species showed significant differences as the aircraft operating state changed. OVOCs were the dominant species and accounted for 63.17%, 58.44%, and 51.60% of the total VOC mass concentration during the taxiing, approach, and take-off stages. Propionaldehyde and acetone were the main OVOCs, and dichloromethane and 1,2-dichloroethane were the main halohydrocarbons. Propane had the highest proportion among all alkanes, while toluene and benzene were the predominant aromatic hydrocarbons. Compared with the source profiles of VOCs from construction machinery, the proportions of halogenated hydrocarbons and alkanes emitted from aircraft were significantly higher, as were those of propionaldehyde and acetone. OVOCs were still the dominant VOC species in aircraft emissions, and their calculated ozone formation potential (OFP) was much higher than that of other VOC species at all stages of aircraft operations. Acetone, propionaldehyde, formaldehyde, acetaldehyde, and ethylene were the greatest contributors to ozone production. This study comprehensively measured the distribution characteristics of VOCs, and its results will aid in the construction of a source profile inventory of VOCs emitted from aircraft sources in real atmospheric environments.

Characterizing VOCs emissions of five packaging and printing enterprises in China and the emission reduction potential of this industry

The packaging and printing industry has become an important source of industrial volatile organic compounds (VOCs) emissions in China, due to the abundant consumption of organic materials. Effective control measures must be developed which rely on a comprehensive understanding of both current emission characteristics and future emission projections. However, representative VOCs source profiles and updated EFs of packaging and printing industry in China are still lacking. In order to fully explore the VOCs emissions characteristics of packaging and printing industry, field measurements including 17 processes in five packaging and printing factories were conducted in this study. The emission factors (EFs), VOCs source profiles, ozone formation potential (OFP) and secondary organic aerosols potential (SOAP) of 110 VOCs species were acquired. Speciated VOCs emission inventory of packaging and printing industry was compiled based on the activity data in 2020. The future reduction perspectives of packaging and printing industry in China were projected. The VOCs EFs of different materials were estimated, including solvent-based ink (287 g/kg), water-based ink (117 g/kg), soybean oil ink (44 g/kg), UV curing ink (22 g/kg), solvent-based adhesive (420 g/kg), and water-based adhesive (139 g/kg). The VOCs EFs of products were 35.58 kg/t for plastic wrapper, 7.28 g/m2 for soft package plastic, 0.083 g/piece for carton, 0.54 g/piece for tin case, and 0.14 g/piece for aluminum can. The total VOCs emissions in Chinese packaging and printing industry was estimated to 634.32 Gg in 2020. Guangdong, Zhejiang, Jiangsu, Fujian, Shandong, and Sichuan contributed 73% to total VOCs emissions. Printing workshop was the main contributor to both primary emission and secondary pollutant generation. OVOCs was the most abundant specie in three sub-industries. The key VOCs species in PF were ethylacetate, ethanol, 2-pentanone, methyl ethyl ketone, and i-propanol. I-propanol, ethanol, m-tolualdehyde, and dichloromethane were dominated in PP. Ethanol, m/p-xylene, i-propanol, o-xylene, and acetaldehyde were the key species in MC. The key VOCs species to OFP and SOAP were ethanol, methyl ethyl ketone, 2-pentanone, ethyl methacrylate, acetaldehyde, toluene, and xylene, which should be prioritized. The VOCs emissions would be reduced by 46.5% in 2025 and 66.4% in 2030 with stringent control measures. Increasing the usage proportion of low-VOCs-contained raw material and improving treatment efficiency are the key technologies to reduce the VOCs emissions in the packaging and printing industry.

Emission factors and source profiles of VOCs emitted from coke production in Shanxi, China

Coking plants in China generate a substantial amount of volatile organic compounds (VOCs). The emission factors (EFs) of VOCs from coking plants are not well known, and thus, this study characterized the VOCs in the emissions from four coking plants in Shanxi, China. The EFs of VOCs from different stages of the coking process were calculated, and coal charging exhibited the highest EFs of VOCs, followed by the flue gases from combustion of coke oven gas, wastewater treatment, coke pushing and chemical byproduct recycling. The VOCs in emissions differed by coking process. Alkanes, aromatics and alkenes were the main VOCs emitted during the coking, wastewater treatment and chemical byproduct recycling processes, respectively. To effectively control the contribution of VOCs from coking processes to secondary organic aerosols and ozone formation, attention should be given to wastewater treatment and coal loading processes. The mean annual weight of VOCs emitted from coking plants in China from 2019 to 2021 was estimated to be 32.91 Gg with coking, chemical byproduct recycling, and wastewater treatment processes accounting for 91.34%, 7.85%, and 0.80% of total VOCs, respectively. An uneven spatial distribution of VOCs emissions in China was identified, with Shanxi, Shaanxi, Hebei, Inner Mongolia and Shandong being the largest contributors.

Differences in compositions and effects of VOCs from vehicle emission detected using various methods

Vehicle exhaust and oil fuel evaporation emit volatile organic compounds (VOCs). The differences in VOC compositions and their effects determined using different methods have not been addressed sufficiently. In this study, VOC samples are obtained from single gasoline and diesel vehicle exhausts using a portable emission measurement system, from a tunnel in Yichang City, and from gasoline and diesel evaporation at gas stations. A total of 107 VOCs are analysed. The calculated VOC source profiles (based on VOC source profiles of single-vehicle type and vehicle fleet composition in the tunnel) and the tested source profiles (from a tunnel test) are compared. The results show that gasoline burning can reduce alkenes from a mass fraction of 53.1% (for evaporation) to 3.6% (for burning), as well as increase the mass fraction of alkenes from 1.3% (for diesel evaporation) to 34.0% (for diesel burning). The calculated VOC source profiles differed from the tested VOC source profiles, with a coefficient of divergence of 0.6. Ethane, ethylene, n-undecane, and n-dodecane are used to distinguish VOCs in gasoline and diesel exhausts. Cis-2-butene, 2-methylpentane, m/p-xylene, o-xylene, and n-decane can be used to separate gasoline from diesel. The xylene/ethylbenzene ratios accurately reveal the photochemical age. Gasoline burning increases health risks associated with VOCs compared with gasoline evaporation. Furthermore, it modifies the main contributor to ozone formation potential. This study is expected to facilitate refined VOC source apportionment and studies pertaining to speciated emission inventories.

Review on Source Profiles of Volatile Organic Compounds (VOCs) in Typical Industries in China

The source profile of volatile organic compounds (VOCs) is essential for establishing reactivity- and toxicity-based emission inventories and developing effective air pollution control strategies. In this paper, the establishment of VOC source profiles and the VOC emission characteristics are reviewed in the petrochemical, solvent use, and chemical industries, and the most up-to-date profiles of the three industries in China are compiled via necessary adjustment and reconstruction of the test data from the literature. Alkanes dominated and OVOCs were often neglected in the overall petrochemical industry and refined processes. They accounted for 60.6% and 3.2% in the merged profiles. Aromatics and OVOCs dominated in the industrial solvent use industry. OVOCs were the most prevalent in the printing and dyeing industries, furniture manufacturing industries, and automobile coating process, whereas aromatics were major contributors of the total VOCs in metal surface coating, shipping coating, and other surface coating industries in the merged profiles. A wide range of products and limited profile studies were obtained in chemical industry, and the compositions of VOCs varied significantly in the production of 30 products in the merged profile. The future research directions of VOC source profiles are discussed, mainly focusing on the sampling, establishment, and evaluation of VOC profiles.

Impact of Water-Based Coating Substitution on VOCs Emission Characteristics for the Surface-Coating Industries and Policy Effectiveness: A Case Study in Jiangsu Province, China

As solvent-based coatings are gradually phasing out in China, the volatile organic compounds (VOCs) emission characteristics of surface-coating industries have changed rapidly. Sector-based field measurements were conducted to build VOCs emission factors and source profiles of surface-coating industries in Jiangsu Province. A VOCs emission inventory was developed, and the projections for 2020 to 2030 were set. It was found that VOCs content in water-based coatings is 50.8% of solvent-based coatings on average. VOCs emission factors of solvent-based coatings ranged from 0.40 to 0.51 kg kg−1, while those of water-based coatings ranged from 0.14 to 0.24 kg kg−1. Compared to solvent-based coatings, the proportion of aromatics emitted from water-based coatings was 44.2% lower, while the proportion of oxygenated VOCs (OVOCs) was 11.6% higher. The results showed that VOCs emissions were about 134 Gg in Jiangsu Province in 2020, of which the solvent-based coating sources contributed 79.6% of the total. Aromatics were the main species contributing 52.9% of VOCs emissions and 85.9% of ozone formation potential (OFP). According to emission prediction results of four scenarios, the emission reduction of implementing low-content VOCs coating substitution is 8.7% higher than that of adopting the best available end-of-pipe treatment measures by 2030.

Emission characteristics, environmental impact assessment and priority control strategies derived from VOCs speciation sourcely through measurement for wooden furniture-manufacturing industry in China

Volatile organic compounds (VOCs) from wooden furniture-manufacturing industry is an important emission source. The VOC content levels, source profiles, emission factors and inventories, O3 and SOA formation, and priority control strategies were investigated from the source. One hundred sixty-eight representative woodenware coatings were sampled, and VOC species and contents were determined. The VOC, O3 and SOA emission factors per gram of coatings for three types of woodenware coatings were quantified. The total VOC, O3 and SOA emissions from wooden furniture-manufacturing industry in 2019 were 976,976 t/a, 2,840,282 t/a, 24,970 t/a, and solvent-based coatings accounted for 98.53 %, 99.17 % and 99.6 % of the total VOC, O3 and SOA emissions, respectively. Aromatics and esters were major organic groups, contributing 49.80 % and 36.03 % to total VOC emissions, respectively. Aromatics contributed 86.14 % and 100 % to total O3 and SOA emissions, respectively. The top 10 species contributing to VOC, O3 and SOA had been identified. Four benzene series, including o-Xylene, m-Xylene, toluene and ethylbenzene, were ranked as the first-class priority control species, accounting for 85.90 % and 99.89 % of the total O3 and SOA, respectively. Priority should be given to solvent-based coatings, aromatics and four benzene series for future O3 and SOA reduction for wooden furniture-manufacturing industry.

Emission factors and source profiles of volatile organic compounds from typical industrial sources in Guangzhou, China

Volatile organic compounds (VOCs) are important precursors of ozone (O3) and fine particulate matter (PM2.5). An accurate depiction of the emission characteristics of VOCs is the key to formulating VOC control strategies. In this study, the VOC emission factors and source profiles in five industrial sectors were developed using large-scale field measurements conducted in Guangzhou, China (100 samples for the emission factors and 434 samples for the source profile measurements). The emission factors based on the actual measurement method and the material balance method were 1.6–152.4 kg of VOCs per ton of raw materials (kg/t) and 3.1–242.2 kg/t, respectively. The similarities between the emission factors obtained using these two methods were examined, which showed a coefficient of divergence (CD) of 0.34–0.72. Among the 33 subdivided VOC source profiles developed in this study, sources including light guide plate (LGP), photoresist mask, and plastic products were the first time developed in China. Due to regional diversities in terms of production technologies, materials, and products, the emission characteristics of the VOCs varied, even in the same sector, thereby demonstrating the importance of developing localized source profiles of VOCs. The ozone formation potential (OFP) of the shipbuilding and repair sector from fugitive emissions was the highest value among all the industrial sectors. Controlling the emissions of aromatics and OVOCs was critical to reducing the O3 growth momentum in industrial sectors. In addition, 1,2-dibromoethane showed high carcinogenic risk potentials (CRPs) during most of the industrial sectors and should be prioritized for controlling.

Volatile organic compound emissions from typical industries: Implications for the importance of oxygenated volatile organic compounds

Industrial productions emit large reactive volatile organic compounds (VOCs) into atmosphere, affecting tropospheric atmospheric chemistry and human health. In this study, VOC samples of industrial process and solvent use were collected from typical industries. The mass concentrations of total VOC (TVOCs) were 34.10 ± 35.46 mg m−3 (mean ± 95% C.I.) measured in industrial process and 25.39 ± 16.88 mg m−3 in solvent use. Difference of VOC profiles between industrial process and solvent use was revealed. Much higher concentrations or percentages of halocarbons were emitted from industrial process, while more abundant alkanes were measured in solvent use. The relative proportions of B:T:E (benzene, toluene and ethylbenzene) were similar for these two industrial sources, but quite different from that of combustion sources. Different ratios of F/A (formaldehyde/acetaldehyde) and A/P (acetaldehyde/propionaldehyde) were found between industrial process and solvent use, suggesting that the ratios might be used as the references to distinguish these two industrial sources. The oxygenated VOCs (OVOCs) were the largest VOC group and ranked No.1 contributor of ozone formation potentials (OFPs) in these two sources. Our results provide the source profiles of industrial VOCs and emphasize the contribution of industrial OVOCs in ozone formations.

Spatially Resolved Source Apportionment of Industrial VOCs Using a Mobile Monitoring Platform

Industrial emissions of volatile organic compounds (VOCs) directly impact air quality downwind of facilities and contribute to regional ozone and secondary organic aerosol production. Positive matrix factorization (PMF) is often used to apportion VOCs to their respective sources using measurement data collected at fixed sites, for example air quality monitoring stations. Here, we apply PMF analysis to high time-resolution VOC measurement data collected both while stationary and while moving using a mobile monitoring platform. The stationary monitoring periods facilitated the extraction of representative industrial VOC source profiles while the mobile monitoring periods were critical for the spatial identification of VOC hotspots. Data were collected over five days in a heavily industrialized region of southwestern Ontario containing several refineries, petrochemical production facilities and a chemical waste disposal facility. Factors associated with petroleum, chemical waste and rubber production were identified and ambient mixing ratios of selected aromatic, unsaturated and oxygenated VOCs were apportioned to local and background sources. Fugitive emissions of benzene, highly localized and predominantly associated with storage, were found to be the dominant local contributor to ambient benzene mixing ratios measured while mobile. Toluene and substituted aromatics were predominantly associated with refining and traffic, while methyl ethyl ketone was linked to chemical waste handling. The approach described here facilitates the apportionment of VOCs to their respective local industrial sources at high spatial and temporal resolution. This information can be used to identify problematic source locations and to inform VOC emission abatement strategies.

Species profile and reactivity of volatile organic compounds emission in solvent uses, industry activities and from vehicular tunnels

A survey was conducted of the volatile organic compounds (VOCs) released from sources of solvent use, industry activities and vehicle emissions in Guiyang, a capital city of China. Samples were collected by canisters and analyzed by GC-MS-FID. The species profiles of VOCs emitted from sources were obtained. Results showed that xylenes, ethylbenzene, acetone and dichloromethane were the characteristics species for painting, 2-propanol and ethyl acetate for printing, α-pinene for solid wood furniture manufacturing, and 2-butanone for biscuit baking. These characteristics species could be as tracers for the sources respectively. In most of samples from the solvent use, the benzene/toluene (B/T) ratio was less than 0.3, indicating that the ratio could be as the indicator for tracing the solvent use related sources. The results also suggested that the toluene/xylene (T/X) ratio be as the indicator to distinguish the VOCs sources of painting (<2) from the printing (>2). Aromatics contributed the most to ozone formation potential (OFP) of most painting and non-paper printing sources, and oxygen-containing VOCs (OVOCs) were major species contributing to OFP of the sources from food production and paper printing. The OFP of the VOCs emissions from vehicle in tunnels and from other manufactures were dominated by both aromatics and alkenes. The α-pinene could explain 56.94% and 32.54% of total OFP of the VOCs sources from filing cabinet and solid wood furniture manufacturing, which was rarely been involved in previous studies of VOCs source profiles, indicating that the species of concern for VOCs sources are still insufficient at present.

Integrated assessment of volatile organic compounds from industrial biomass boilers in China: emission characteristics, influencing factors, and ozone formation potential.

Industrial biomass boilers (IBBs) are widely promoted in China as a type of clean energy. However, they emit large amount of volatile organic compounds (VOCs) and the emission characteristics and the underlying factors are largely unknown due to the sampling difficulties. In this study, three wood pellet-fueled and two wood residue-fueled IBBs were selected to investigate the characteristics of VOC emissions and to discover their underlying impacting factors. The emission factor of VOCs varied from 21.6 ± 2.8mg/kg to 286.2 ± 10.8mg/kg for the IBBs. Oxygenated VOCs (OVOCs) were the largest group, contributing to 30.3 - 73.6% of the VOC emissions. Significant differences were revealed in the VOC source profiles between wood pellet-fueled and wood residue-fueled IBBs. Operating load, excess air, furnace temperature, and fuel type were identified as the primary factors influencing VOC emissions. The excess air coefficient should be limited below 3.5, roughly corresponding to the operating load of 62% and furnace temperature of 630°C, to effectively reduce VOC emissions. VOC emissions also showed great differences in different combustion phases, with the ignition phase having much greater VOC emissions than the stable combustion and the ember phases. The ozone formation potential (OFP) ranged from 4.3 to 31.2mg/m3 for the IBBs, and the wood residue-fueled IBBs yielded higher OFP than the wood pellet-fueled ones. This study underscored the importance of OVOCs in IBB emissions, and reducing OVOC emissions should be prioritized in formulating control measures to mitigate their impacts on the atmospheric environment and human health.

New understanding of source profiles: Example of the coating industry

The source profiles of VOCs in the industry are closely related to the raw and auxiliary materials, process characteristics and waste gas treatment of the enterprise, as well as the number of VOCs that can be identified by analytical methods. In the process of industry transformation, it is necessary to update the source profiles. This study selects the coating industry as a case study as it is in a transitional stage and has high volatile organic compounds (VOCs) production and odor complaints. The VOCs emissions in seven coating enterprises in 2019 were studied using a broad-spectrum and high species identification rate analysis method to identify many new species of VOCs, which increased the total emissions by 6.4 times compared with previous studies. A total of 26 new types of VOCs pollutants were identified, especially the number of oxygenated VOCs species increased by 3.1 times, and proved that butyl acetate replaced the benzene series to become was the new dominant species in the coating industry. And the average ozone formation potential (OFP) of coating industry was 2.6 times the measurement result of the classic method of PAMs and TO15. The source reactivity increased on average by 366.7%.

Impacts of applying ethanol blended gasoline and evaporation emission control to motor vehicles in a megacity in southwest China

The use of ethanol blended gasoline and evaporation emissions control are effective means to reduce air pollutant emissions from motor vehicles. However, there is currently a lack of comprehensive assessment of the impact of these measures on air quality, in particular to control volatile organic compounds (VOCs), an important precursor to PM2.5 and O3 formation. Therefore, this study sets up different motor vehicle pollution control scenarios based on ethanol gasoline substitution and evaporative emission control, respectively. The emission changes of atmospheric pollutants, O3 formation potential (OFP) and VOCs species from motor vehicles under each control scenario were analyzed, and the chemical transport model WRF/CMAQ was used to evaluate the changes of pollutant concentration in the ambient air under different scenarios. The results show that the VOCs emissions from motor vehicles in Chengdu increased by 25% from 2014 to 2019, which is attributed to the rapid growth of motor vehicle population and the aggravation of road congestion. Under different control scenarios, the emission of NOx, VOCs and PM2.5 decreased to different degrees, mainly from evaporation emissions control measures. The use of ethanol blended gasoline can reduce the VOCs emissions while increased OFP by 26%, due to the presence of highly reactive species in the VOCs source profiles, which ultimately determined the OFP of motor vehicles. Thus, it is necessary to the control of alkenes, aromatics, oxygenated VOCs (OVOCs) and other highly reactive characteristic emission species of gasoline vehicles. The simulation results of model show that under different control scenarios the PM2.5 concentrations decreased to different degrees, the urban area with the maximum decrease rate of 9.0–9.2%. The combination of the use of ethanol blended gasoline and evaporation emissions control had a good effect on PM2.5 concentration control, while the evaporation emissions control of motor vehicles alone can lead to a decrease in O3 concentration, i.e. a decrease by 1.9–2.5%.

A newly integrated dataset of volatile organic compounds (VOCs) source profiles and implications for the future development of VOCs profiles in China

Volatile organic compounds (VOCs) source profiles can be used for a number of purposes, such as creating speciated air pollutant emission inventories and providing inputs to receptor and air quality models. In this study, we first collected and schematically evaluated more than 500 Chinese domestic source profiles from literature and field measurements, and then established a most up-to-date dataset of VOCs source profiles in China by integrating 363 selective VOCs profiles into 101 sector-based source profiles. The profile dataset covers eight major source categories and contains 447 VOCs species including non-methane hydrocarbons (NMHCs) species and oxygenated VOCs (OVOCs) species. The results shown that (1) VOCs composition characteristics exhibit variations for most Level-II source sectors and Level-III sub-sectors even under the same Level-I source category; (2) OVOCs, which were significantly missing in previous profiles, account for more than 95% in cooking and 20– 40% in non-road mobile, biomass burning and solvent use sources; (3) aromatics account for 20%–40% in most emission sources except cooking source, alkenes and alkynes account for ~20% in combustion sources (stationary combustion, mobile source and biomass burning), alkanes are abundant in gasoline-related emission sources(on-road mobile source and fuel oil storage and transportation); (4) missing OVOCs species could bring 30%–50% to ozone formation potentials in most emission sources; and (5) there are considerable differences in VOCs chemical groups and individual species for most emission sources between this dataset and the widely used U.S. SPECIATE database, indicating the importance of developing domestic VOCs source profiles. The dataset developed in this study can help support reactive VOCs species-based ozone control strategy and provide domestic profile data for source apportionment and air quality modeling in China and other countries or regions with similar emission source characteristics.

Sector-based volatile organic compounds emission characteristics from the electronics manufacturing industry in China

Controlling volatile organic compounds (VOCs) is an efficient method for alleviating fine particulate matter (PM2.5) and ozone (O3). This study targeted the electronics manufacturing industry in China, including semiconductor device (SD), printed circuit board (PCB), display device (DD) and electronic terminal product (ETP). The concentration of VOCs was 4.5–86.1 mg m−3; the highest and lowest values were observed in ETP and PCB, respectively. Additionally, the local emission factors were calculated, which were 1.6 × 10−3 t/slice (SD), 9.8 × 10−6 t/m2 (PCB), 2.4 × 10−4 t/slice (DD) and 1.8 × 10−3 t/1000set (ETP), respectively. Meanwhile, sector-based source profiles are also established. Generally, OVOCs were the dominant VOCs group for PCB, DD and ETP, accounting for 92.8%–96.2%, whereas alkanes and halocarbons accounted for a high proportion (70.4% and 24.6%, respectively) in SD. The major species of OVOCs in each sector were similar: n-butyl acetate and acetone in SD and DD, and isopropanol and ethanol in PCB and ETP. However, 2-methylpentane, 3-methylpentane, n-pentane, and trichloroethylene were the major alkanes and halocarbons in SD, respectively, and the sector-based ozone and secondary organic aerosol formation potentials (OFPs and SOAPs) were calculated. This suggests that 2-methylpentane, isopropanol, acetone, ethanol, and m,p-xylene should be preferentially controlled to reduce the OFPs, while m,p-xylene, ethylbenzene, o-xylene, toluene and o-ethyltoluene were the priority control species to reduce SOAPs. Furthermore, the comparison of VOCs source profiles in these four sectors with other places showed that the proportions of individual compounds were different. This study provides a foundation for associated research on VOCs in the electronics manufacturing industry.

Source profiles and reactivity of volatile organic compounds from anthropogenic sources of a megacity in southwest China

Volatile organic compounds (VOCs) from anthropogenic sources are deleterious to air quality, climate, human health and vegetation. However, research on VOCs source profiles of the non-solvent use in some industries and the emission characteristics of motor vehicles under actual road conditions is limited in China. In this research, VOCs source profiles of industries (wood-based panel manufacturing and pharmacy) based on all product processes were constructed, and those of light and medium duty vehicles exhaust based on actual road conditions at different speeds were acquired in Chengdu, a megacity in southwest China. The results show that VOCs groups of various sources were dominated by oxygenated VOCs (OVOCs), which accounted for 27–84% of the total VOCs emission. Due to the great contribution of OVOCs to industrial source reactivity (SR), attention should be paid to the control over the emissions of the species with high reactivity, such as aromatics and alkenes, but also to the production processes with relatively large proportions of OVOCs species emission. VOCs emissions from gasoline and diesel vehicles running at a speed ranging from 0 to 40 km/h have approximately the same ozone formation potential (OFP), while the contribution of VOCs emission from diesel vehicles to the formation of urban ozone pollution deserves further attention. It is found that VOCs emission characteristics of some industries in China have changed as the upgrading of production processes in automobile manufacturing and other industries, such as the extensive use of water-based coatings instead of outdated solvent-based coatings, which increased the uncertainty of judgment parameters (B/T ratio, etc.) in source apportionment research. The ranges of B/T ratio of industrial process sources, solvent use sources and motor vehicles are 0.00–0.23, 0.01–0.75 and 0.35–0.92, respectively. Therefore, updating existing source profiles and further understanding the emission constitutions of characteristic species in these source profiles (such as BTEX ratio) will be conducive to further research on emission inventory, source apportionment for O3 pollution control effectively.

Speciation of VOC emissions related to offshore North Sea oil and gas production

Abstract. The North Sea is Europe's key oil and gas (O&amp;amp;G) basin with the output currently meeting 3 %–4 % of global oil supply. Despite this, there are few observational constraints on the nature of atmospheric emissions from this region, with most information derived from bottom-up inventory estimates. This study reports on airborne measurements of volatile organic compounds (VOCs) emitted from O&amp;amp;G-producing regions in the North Sea. VOC source emission signatures for the primary extraction products from offshore fields (oil, gas, condensate, mixed) were determined in four geographic regions. Measured iso-pentane to n-pentane (iC5 / nC5) ratios were 0.89–1.24 for all regions, used as a confirmatory indicator of O&amp;amp;G activities. Light alkanes (ethane, propane, butane, pentane) were the dominant species emitted in all four regions; however, total OH reactivity was dominated by unsaturated species, such as 1,3-butadiene, despite their relatively low abundance. Benzene to toluene ratios indicated the influence of possible terrestrial combustion sources of emissions in the southern, gas-producing region of the North Sea, seen only during south or south-westerly wind episodes. However, all other regions showed a characteristic signature of O&amp;amp;G operations. Correlations between ethane (C2H6) and methane (CH4) confirmed O&amp;amp;G production to be the primary CH4 source. The enhancement ratio (ΔC2H6/ΔCH4) ranged between 0.03–0.18, indicating a spatial dependence on emissions with both wet and dry CH4 emission sources. The excess mole fraction demonstrated that deepwater oil extraction resulted in a greater proportion of emissions of higher carbon number alkanes relative to CH4, whereas gas extraction, typically from shallow waters, resulted in a less complex mix of emissions dominated by CH4. The VOC source profiles measured were similar to those in the UK National Atmospheric Emissions Inventory (NAEI) for oil production, with consistency between the molar ratios of light alkanes to propane. The largest discrepancies between observations and the inventory were for mono-aromatic compounds, highlighting that these species are not currently fully captured in the inventory. These results demonstrate the applicability of VOC measurements to distinguish unique sources within the O&amp;amp;G sector and give an overview of VOC speciation over the North Sea.

Process-based VOCs Source Profiles and Contributions to Ozone Formation in Typical Organic Solvent-used Industries in Hangzhou

The solvent-used industry plays an important role in volatile organic compounds (VOCs) emission, which has caused an increasing concern. Herein, VOCs samples collected before and after treatments from the painting industry, printing industry and printing & dyeing industry in Hangzhou were measured. Then, the VOCs removal efficiencies of different treatments were detailedly investigated. Among them, high-temperature incineration technology achieved the highest VOCs removal efficiency, averaging 93.0%. Process-based source profiles suggested that aromatics and alkanes accounted for more than 76.5% of VOCs, mainly including toluene, styrene, n-decane, n-undecane and n-dodecane. Furthermore, the ozone formation potentials (OFPs) based on processes suggested that toluene, meta-xylene, n-butene, styrene and ortho-xylene should be preferentially controlled to reduce the OFPs in painting industry and printing & dyeing industry. For printing industry, the contributions of top five species to the OFPs were relatively balanced, which indicated these species should all be given more attention. Finally, the low-temperature plasma technology and the combined technology of activated carbon adsorption with condensation were found to reduce the OFPs for their ability to preferably removing aromatics or olefins. The results were beneficial to develop effective VOCs abatement strategies and complemented the VOCs source profiles in solvent-used industries.