Emission Characteristics Of VOCs Research Articles

Process-specified emission factors and characteristics of VOCs from the auto-repair painting industry

Daily use of passenger vehicles leads to considerable emission of volatile organic compounds (VOCs), which are key precursors to the ground-level ozone pollution. While evaporative and tailpipe emission of VOCs from the passenger vehicles can be eliminated largely, or even completely, by electrification, VOCs emission from the use of coatings in auto-repair is unavoidable and has long been ignored. Here, we present for the first time, to the best of our knowledge, a comprehensive investigation on the emission factors and process-specified characteristics of VOCs from auto-repair painting, based on field measurements over 15 representative auto-repair workshops in the Pearl-River-Delta area, China. Replacement of solvent-borne coatings with water-borne counterparts, which was only achieved partially in the Basecoat step but not in the Putty, Primer and Clearcoat steps, could reduce the per automobile VOCs emission from 756.5 to 489.6 g and the per automobile ozone formation potential (OFP) from 2776.5 to 1666.4 g. Implementation of exhaust after-treatment led to a further reduction of the per automobile VOCs emission to 340.9 g, which is still ca. 42% higher than that from the state-of-art painting processes for the manufacture of passenger vehicles. According to the analysis of VOCs compositions, the Putty process was dominated by the emission of styrene, while Primer, Basecoat (solvent-borne) and Clearcoat steps were all characterized by the emission of n-butyl acetate and xylenes. By contrast, water-borne Basecoat step showed a prominent emission of n-amyl alcohol. Notably, for the full painting process to repair an automobile, n-butyl acetate emerged as the most abundant species in the VOCs emission, whereas xylenes contributed most significantly to the OFP. Scenario analysis suggested that reducing VOCs contents in the coatings, as well as improving the after-treatment efficiency, were highly potential solutions for effective reduction of VOCs emission from auto-repair. Our study contributes to an update of industrial inventories of VOCs emission, and may provide valuable insights for reducing VOCs emission and OFPs from the auto-repair industry.

Evaporative emission characteristics of VOCs from in-use light-duty gasoline vehicles

VOCs are an important precursor pollutant of ozone (O3) and secondary organic aerosols (SOA). Vehicle evaporative emission is an essential source of VOCs in urban area, among which lack of localized tests of running loss process in China. This study tested all the evaporative emission processes of in-use light-duty gasoline vehicles (LDGVs), including refueling, running loss, hot soak, and 48-h diurnal breathing loss (DBL) based on the variable temperature Sealed Housing for Evaporative Determination (VT-SHED) of REU (China 4, China 5) vehicles and REC (China 6, with Onboard Refueling Vapor Recovery system) vehicles. The emission factors (EFs), species profiles, Ozone formation potential (OFP), and SOA formation potential (SOAP) of all evaporative emission processes of REU and REC vehicles were obtained. We found that the running loss emissions was less affected by the Onboard Refueling Vapor Recovery (ORVR) system, the average running loss EFs of REU and REC vehicles was 9.386 mg/km; refueling and DBL EFs of REC vehicles was 1.491 mg/L and 0.179 g/day, respectively, 99.8% and 56.0% lower than those of REU vehicles, the hot soak EFs was 0.087 g/h in average. The refueling emissions process was dominated by alkanes (REU: 77.8%; REC: 75.4%), and C4 and C5 species dominated (REU: 75.6%; REC: 67.6%). Among the running loss, hot soak and DBL emissions, alkanes, oxygenated VOCs (OVOCs) and aromatics were the dominant VOCs groups, OVOCs account for a higher proportion in REC vehicles than in REU vehicles. REC vehicles had higher proportion of C1–C3 than REU vehicles, it may be that ORVR has a better adsorption effect on species with large carbon numbers. Running loss VOCs species had a strong correlation with hot soak VOCs species. The OFP of running loss in REU and REC vehicles were 0.9–1.3 and 0.3–0.7 times higher than those of refueling and 48-h DBL, while the SOAP were 10.7–12.9 and both 1.1 times higher, respectively. These findings can provide valuable basis for emission estimation and characteristic analysis for evaporative process of LDGVs and support the development of appropriate pollution-control policy.

Determining an optimal control strategy for anthropogenic VOC emissions in China based on source emissions and reactivity

An evidence-based control strategy for emission reduction of VOC sources can effectively solve the regional PM2.5 and O3 compound pollution in China. We estimated the anthropogenic VOC emission inventory in China in 2018 and established a source profile database containing 129 sources based on localized detection and the latest research results. Then, the distribution of the ozone formation potential (OFP) and secondary organic aerosol formation potential (SOAFP) for emission sources was analyzed. Moreover, priority control routes for VOC emission sources were proposed for different periods. Anthropogenic VOC emissions in China reached 27,211.8 Gg in 2018, and small passenger cars, industrial protective coatings, biomass burning, heavy trucks, printing, asphalt paving, oil storage and transportation, coking, and oil refining were the main contributors. Industrial protective coatings, small passenger cars, and biomass burning all contributed significantly to OFP and SOAFP. Priority in emission reduction control should be given to industrial protective coatings, small passenger cars, heavy trucks, coking, printing, asphalt paving, chemical fibers, and basic organic chemical sources over the medium and long term in China. In addition, the priority control route for VOC emission sources should be adjusted according to the variations in VOC emission characteristics and regional differences, so as to obtain the maximum environmental benefits.

Emission Characteristics and the Environmental Impact of VOCs from Typical FRP Manufacture Industry

The VOC emission characteristics of the typical fiber-reinforced plastics (FRPs) industry were studied for an assessment of the impact on the environment. The results showed that the VOC emissions of the typical FRP industry mainly come from grille, sheet, winding, molding, and pultrusion process links, including ketones, aldehydes, alcohols, and benzene series. The benzene series’ concentration represented by styrene was much higher than that of other species. The generation potential of ozone and the SOA in the typical production process were evaluated: in terms of ozone impact, the OFP values of the winding process were the highest, accounting for 65.9% of the total contribution. For the component contribution, the OFP contribution of the benzene series represented by styrene was far more than that of other VOC species, and the styrene mainly came from the use of unsaturated resin. In terms of the SOA impact, the pultrusion process contributed the most to the generation of SOA, accounting for 63.9% of the total SOA contribution. In terms of the component contribution, the contribution of SOA mainly came from the benzene series, accounting for nearly 95% of the total contribution of VOCs. Therefore, FRP enterprises should give priority to controlling the emission of the benzene series.

Emission Characteristics of PM (PMtotal, PM10, PM2.5), NOx, CO and VOCs Emitted from LNG-fired Gas Turbine and Small Domestic Boiler

In recent years, natural gas is increasingly being used in the heating and power generation sectors as a clean fuel with an aim to reduce air pollution. In this study, a standard test method was used to measure air pollutants and identify emission characteristics for gas turbines and small domestic boilers, which use LNG as fuel. For gas turbines, the air pollutants were measured at 14 sites, whereas for small domestic boilers, six of them were installed in a laboratory to run tests due to limitations in on-site measuring and testing. However, the small domestic boilers were all new machines and were operated for long consecutive hours for testing, meaning that the results could vary from that of on-site boilers. The results show that gas turbines and small domestic boilers not only emit PM2.5, but also particulate matters larger than PM2.5. According to the measurements, the average concentration level of PMtotal, PM10, and PM2.5 generated from gas turbines are 51.8, 38.5, and 28.1 µg/m3 (@O2 15%), respectively. Those generated from small domestic boilers were 31.3, 26.2, and 20.0 µg/m3 (@O2 4%), respectively. The NOx concentration levels complied with the emission limits. Especially where a NOx control device was in place, both the NOx and CO concentration levels were relatively low. However, the NOx and CO concentration levels were generated from small domestic boilers were relatively high, since the emission limits were not applied. VOCs were measured at 10 facilities where 28 samples were collected. The compounds that were identified were Aromatics, Oxygenated VOCs, Alkanes, in that order, which were consistent across the samples. Aromatics consisted mostly of toluene, o,m,p-xylenes, benzene, and ethylbenzene. Among oxygenated VOCs, ethyl acetate, vinyl acetate, and isopropyl alcohol, etc. were identified. In other words, gas turbines generated a wider range and higher concentration levels of VOCs compared to small domestic boilers. The emission factors of gas turbines and small domestic boilers were derived from the measurements, and then compared with the standard emission factors of other countries (NAER, U.S. EPA AP-42, EMEP/EEA). PM emission factors calculated in this study were lower than that of existing emission factors and the calculated NOx emission factors (uncontrolled) for the small boilers were also lower. The CO emission factor for gas turbines was lower than that of existing emission factors, but higher for the small domestic boilers. Emission factors of benzene, toluene, and xylenes, which are hazardous air pollutants, were lower than those of U.S. EPA AP-42.

Emission Characteristics and Environment Impacts of VOCs from Typical Rubber Manufacture

The emission characteristics of VOCs from three typical rubber manufacture industries were studied by GC-MS/FID. Maximum incremental reactivity(MIR) and fractional aerosol coefficient(FAC) were employed to evaluate the ozone formation potential(OFP) and secondary organic aerosol(SOA) formation potential. The results show that the VOC types emitted from the manufacturing of rubber products mainly include alkanes, ketones, aldehydes, alcohols, and benzene series. For traditional rubber products manufactured through rubber mixing and vulcanization, the main pollutants are ketones and alcohols, whereas for production processes involving gluing and painting, the main pollutants belong to the benzene series. In terms of ozone impact, the traditional processes contribute to ozone formation mainly through oxygenated hydrocarbons. In industries that utilize adhesives and paints, the extensive use of these organic solvents lead to a significantly higher contribution of the benzene series than other VOC species to ozone formation; the benzene series account for 82.9% of the total contribution. In terms of SOA impact, the benzene series are the main contributor to SOA, whereas the contribution of VOCs from traditional processes is small; hence, SOA primarily originates from the gluing and painting processes. Therefore, in traditional production of rubber products through rubber mixing and vulcanization, the emission of oxygenated hydrocarbons should be preferentially controlled, whereas for rubber industries utilizing gluing and painting processes, the emission of benzene series should be preferentially controlled.

Source Profiles and Impact of VOCs Based on Production Processes in Foundry Industries

The characteristics of the VOCs species in foundry industries based on the production processes were analyzed through gas chromatography-mass spectrometry (GC-MS) after sampling the emissions of VOCs in 9 typical foundry enterprises using air packages and absorption tubes. The source profiles of the VOCs species in foundry industries based on production processes were established for the first time in China. In addition, the emission characteristics of VOCs and the contribution of VOCs emitted by various production processes to ozone generation were also studied. The results showed that the characteristic components of the VOCs in foundry industries were predominantly aromatic hydrocarbons, halogenated hydrocarbons, and oxygenated hydrocarbons. The average concentrations were 50.9%, 20.8%, and 12.6%, respectively. In general, aromatic hydrocarbons, such as toluene, benzene, and m/p-xylene; halogenated hydrocarbons, such as trichloroethylene and dichloromethane; oxygenated hydrocarbons, such as acetone, ethyl acetate, cyclopentanone, and some alkanes, were the primary VOCs species of the foundry industries. The emission characteristics of different production processes were related to the solvents and surface treating agents used by each process. The results also demonstrated that painting was the largest contributor of VOCs concentrations among all the production processes, followed by the modeling procedure and the silica sol and pouring processes. The OFP values for the different production processes ranged from 0.29-96.09 mg·m-3. Painting was the largest contributor to OFP, followed by the modeling procedure and the melting and pouring processes. Aromatic hydrocarbons and oxygenated hydrocarbons were the dominant contributors to OFP, and 1,3,5-trimethylbenzene, 1,2,4-trimethylbenzene, toluene, and m/p-xylene were the main active components in the foundry industry, with a total contribution to the ozone generation potential of nearly 60%. It is suggested that the painting process should be prioritized regarding control measures to reduce its emissions and impact, while the waste gas from the modeling procedure and the melting and pouring processes should be collected efficiently and treated properly before being discharged to the environment.

Emission profiles, ozone formation potential and health-risk assessment of volatile organic compounds in rubber footwear industries in China.

The emission characteristics of VOCs in the rubber footwear industry (RFI) and its effect on human health are poorly understood to date. Herein, up to 68 VOCs, sorted into seven classes including alkanes, alkenes, acetylene, aromatics, halocarbons, carbon disulfide, and oxygenated VOCs, were monitored. VOCs emitted from three main processing stages of RFI, including shaping, painting and vulcanizing, were 383, 1507 and 1026 mg/m3, respectively. The top 10 VOCs contributing to the concentration and ozone formation potential were identified. Generally, alkanes were the major component emitted from three stages, contributing 48.58%-63.07% of the total VOCs. Alkenes contributed most to the OFP, accounting for 37.2%-69.1%. Based on the risk assessment, a definite cancer risk for workers in shaping workshop should be noticed. Several VOCs with a life carcinogenic risk higher than 10-4, especially benzene, bromodichloromethane, ethylbenzene and 1,1,2-trichloroethane, should be focused on. Therefore, more attention should be taken for the extended-ranges of VOCs in subordinate RFI, except for the publicly concerned aromatics in rubber industry. A VOCs emission inventory from the production process of Chinese RFI in 2000-2016 was compiled. It is estimated that Chinese RFIs have emitted a total of 319 × 104 t VOCs in those past 17 years.

소형챔버를 이용한 드라이클리닝 모직물 목도리의 휘발성유기화합물 방출 특성

소형챔버를 이용한 드라이클리닝 모직물 목도리의 휘발성유기화합물 방출 특성

A study for predicting the VOC emission characteristic of adsorbent blended building materials

The excellent adsorption properties of adsorbent can form effective adsorption and fixation of VOC molecules. Therefore, some scholars have proposed to control the VOC emission of building materials by adding adsorbent. Most adsorbents and building materials are porous media, however, there are great differences between their microstructures. The emission characteristics of the adsorbent blended building materials are also different from the original building materials. Based on the analysis of micro mass transfer mechanism of VOC molecules in building materials, this paper developed a theoretical prediction system for the characteristic parameters of the VOC emission from adsorbent blended building materials, by which the new VOC emission characteristics of the low-emission building materials can be predicted. This study is significant for optimizing the blending ratios and methods of adsorbent for engineering application, and it can provide a basis for designing efficient VOC control strategies.

Long-term indoor gas pollutant monitor of new dormitories with natural ventilation

New furniture and wood-based decoration are the major sources of gas pollutant in indoor environments. Ventilation is the most straightforward approach to eliminate the indoor gaseous pollution. There were many studies investigating the VOC emission characteristics of various building materials, but people still can’t answer the question that how long should we ventilate for an acceptable indoor concentration level in the real life. This study monitors the long-term gas pollutant concentration of 14 new student dormitory rooms with newly furnitured beds, desks and closets. The formaldehyde, TVOC, and ammonia concentrations were measured, the concentration of detected composition of VOCs was listed, and the decay rate under natural ventilation was analyzed. To determine the natural ventilation rate, the traditional tracer gas method and fast VOC decay method were compared, then a quick ventilation rate method was proposed. The VOC emission rate from the furniture was also measured at different times during the whole testing period. As the field measurement has many un-controlled factors, a small single room model was built and furnitured with corresponding loading amount of furniture board materials. The influence of furniture density, supplier and room location on VOC emission rates was also analyzed.

On-road emission characteristics of VOCs from light-duty gasoline vehicles in Beijing, China

This study is the third in a series of three papers aimed at characterizing the VOC emissions of vehicles in Beijing. In this study, 30 light-duty vehicles fueled with gasoline were evaluated using a portable emission measurement system (PEMS) as they were driven on a predesigned, fixed test route. All of the tested vehicles were rented from private vehicle owners and spanned regulatory compliance guidelines ranging from Pre-China I to China IV. Alkanes, alkenes, aromatics and some additional species in the exhaust were collected in Tedlar bags and analyzed using gas chromatography/mass spectrometry (GC–MS). Carbonyls were collected on 2,4-dinitrophenyhydrazine (DNPH) cartridges and analyzed using high-performance liquid chromatography (HPLC). Overall, 74 VOC species were detected from the tested vehicles, including 22 alkanes, 6 alkenes, 1 alkyne, 16 aromatics, 3 cyclanes, 10 halohydrocarbons, 12 carbonyls and 4 other compounds. Alkanes, aromatics and carbonyls were the dominant VOCs with weight percentages of approximately 36.4%, 33.1% and 17.4%, respectively. The average VOC emission factors and standard deviations of the Pre-China I, China I, China II, China III and China IV vehicles were 469.3 ± 200.1, 80.7 ± 46.1, 56.8 ± 37.4, 25.6 ± 11.7 and 14.9 ± 8.2 mg/km, respectively, which indicated that the VOC emissions significantly decreased under stricter vehicular emission standards. Driving cycles also influenced the VOC emissions from the tested vehicles. The average VOC emission factors based on the travel distances of the tested vehicles under urban driving cycles were greater than those under highway driving cycles. In addition, we calculated the ozone formation potential (OFP) using the maximum incremental reactivity (MIR) method. The results of this study will be helpful for understanding the true emission levels of light-duty gasoline vehicles and will provide information for controlling VOC emissions from vehicles in Beijing, China.

냉간모드에서의 이륜자동차 VOCs 배출특성연구

냉간모드에서의 이륜자동차 VOCs 배출특성연구

Emission Characteristics of Particulate Matters and VOCs in Cow Dung Combustion

Emission Characteristics of Particulate Matters and VOCs in Cow Dung Combustion Biomass fuel has been greatly used for cooking especially in developing countries and several studies have concentrated on the toxicity level of the combustion emissions. This study focused on the characteristics of particulate matter(PM) and VOCs from cow dung combustion. Data collection and results from the combustion were taken from the usage of a dual cone calorimeter, in which it showed that the heatflux, 50kW/m2 has the highest CO2 yield having 1,407.7138.2 mg/kg. When the temperature is high, the combustion will also increase. The concentrations of PM and VOCs were determined using a dust spectrometer and gas chromatography/mass spectrometry, respectively. The outcome of the tests presented that PM10 concentration were highest at 15kW/m2 with a total of 1,660.0709.5 g/m3. On the other hand, VOCs like benzene and toluene were detected during lower combustion temperature. Higher heat rate may cause an ample amount of CO2 concentration release, however, it also causes some VOCs and ultrafine dusts undetected. The generation of ultrafine dusts and VOCs was particularly high when the combustion temperature was low. .

A numerical simulation of VOC emission and sorption behaviors of adhesive-bonded materials under floor heating condition

The objective of this study is to investigate the VOC emission and sorption characteristics of adhesive-bonded materials under floor heating condition. The study focuses on adhesive-bonded materials covering a large surface area, such as plywood flooring/epoxy adhesive assembly as an emission-dominated material, and PVC wallpaper/starch-based adhesive/gypsum board assembly as a sorption-dominated material, installed in a residential housing unit equipped with a radiant floor heating system. The numerical analysis based on mass transfer model is used, and the model was validated, by comparing the simulated results with previously published experimental data. Comparative simulation of emission and sorption between the single finishing material and composite material was performed. With respect to VOC emission, the simulation results showed that the epoxy adhesive allowed a stronger emission from the plywood flooring composite, and also the adhesive effect on VOC emission was shown to become significant under floor heating condition. Another simulation on VOC sorption demonstrated that the starch-based adhesive appeared to increase sorption strength and period. Also, it showed that the adhesive may play a role of mass transfer bridge between the finishing material and substrate, allowing a stronger sorption when low-VOC gypsum board was used as a substrate. The presence of adhesive due to the bonding method can affect the emission and sorption of building finishing materials. The impact on indoor air quality when emission- and sorption-dominated adhesive-bonded materials coexist in a floor heated space was also discussed.

Evaluation of VOC emission and sorption characteristics of low-VOC adhesive-bonded building materials

To reduce the risk of indoor air pollution caused by synthetic building materials, low-volitile organic compounds (VOC) building materials, including adhesives, are commonly used in building construction. Although adhesives do not directly contact indoor air, they affect VOC mass transfer at the surface of finishing materials by diffusion. This study investigates VOC emission and sorption behaviors of building materials with low-VOC adhesives. Small chamber emission and sorption experiments were designed in parallel to field measurements to examine the onsite VOC emission and sorption rates of adhesive-bonded building materials. It was found that the onsite emission rates from a wallpaper composite (polyvinyl chloride wallpaper + paper adhesive + gypsum board) were higher than the emission rates detected in the small-scale chamber, which demonstrates the possible sorption effect of the wallpaper composite. The results of the sorption chamber experiment confirm that the wallpaper is a sorptive building material and that the bonding of wallpaper to gypsum board increases the sorption and re-emission rates. These results indicate that even though low-VOC adhesive-bonded materials are used, additional indoor air quality control techniques should be applied to minimize re-emission by sorption processes over long periods of time.

Determination of the equivalent emission parameters of wood-based furniture by applying C-history method

VOC pollution in indoor air has become a serious problem in urban areas of China. Building materials and furniture used indoors are the main sources of such pollution. How to determine the VOC emission characteristics of furniture rapidly and conveniently is an important but difficult problem. In this paper, we extend the C-history method for determining the VOC emission characteristic parameters (i.e., the initial emittable VOC concentration, C 0 , the partition coefficient, K , and the diffusion coefficient, D ) of homogeneous building materials developed by Xiong et al. (2011a) to measure the parameters of VOC emissions from wood-based furniture in a 30 m 3 full-scale chamber. The conditions under which there are three equivalent parameters, C 0,equ , K equ and D equ for multi-layer board and wood-based furniture is analyzed and presented. A series of tests were performed to determine the three parameters of some commonly used wood-based furniture in China. A run of independent ventilated chamber experiments were carried out to validate the method. The results show that: (1) The agreement of the formaldehyde and six VOCs concentrations between the ventilated experiment and the simulated results based on the determined parameters is very good; (2) The method could be used in testing multi-layer board and wood-based furniture. The testing time is usually less than 3 days as compared with the furniture testing method typically performed under ventilated chamber conditions and take 5,7,14 or 28 days. The possibilities and limitations of applying the method to the existing furniture labeling schemes are discussed. ► Conditions under which there are equivalent parameters for wood-based furniture. ► Applying C-history method in wood-based furniture testing. ► Independent validation method was used during the test. ► Formaldehyde and other six VOCs were selected as targets. ► Reducing the typical testing time to within 3 days.

Predicting emission characteristics of volatile organic compounds from wet surface coatings

A mathematical model is developed to describe the emission characteristics of VOCs from homogeneous wet coating materials deposited on impermeable substrates. The model considers mass transfer in the material and in air, boundary layer resistance and the change in the coating thickness with time due to emission of VOC. Key features of the model are incorporation of concentration dependent VOC diffusion coefficients predicted from a physical model and nonlinear equilibrium isotherm at the coating/air interface. The model is applied to predict emission characteristics of MMA from acrylic based surface coatings. In an attempt to investigate the influences of equilibrium isotherm type and diffusion formalism on the predictions, simulations are performed with either constant or concentration dependent diffusivities and linear or nonlinear equilibrium isotherms. The lowest MMA concentration in air is predicted by incorporating the concentration dependent diffusivity and nonlinear equilibrium isotherm. The results suggest that assuming the diffusivity of MMA constant or equilibrium isotherm linear may lead to wrong conclusions about the emission rates from wet coatings. The model is general, fully predictive and can be used to predict emission rates of different VOCs from different coating materials if diffusion and thermodynamic parameters are available.

Assessment of the Emission Characteristics of VOCs from Interior Furniture Materials during the Construction Process

In this study, the indoor concentrations of pollutants from different materials that are used in kitchens and living rooms are measured during the construction process. The measurements are carried out in three households: the first is built using only conventional materials, the second household uses some environmentally sound materials and the last uses nothing but environmentally sound materials. The construction stage that had the greatest effect on indoor pollutant concentration is evaluated after installing all of the materials and measuring the indoor concentrations throughout the construction process. The pollutant concentration is measured 10 times at different stages of construction and in the days following the completion of construction. Results show that the living room and kitchen furniture made of particle board and MDF emits the largest amounts of pollutants. In addition, of all the pollutants measured, including benzene, toluene, ethylbenzene, styrene, 1,4-dichloro-benzene and formaldehyde, only toluene did not satisfy the Indoor Air Quality Management Act of Korea. The toluene concentration increase rapidly after the introduction of kitchen and living room indoor furniture. This is due to the material of which the furniture is composed and these results are validated using a small chamber method.

VOC Emission Characteristics of Petrochemical Wastewater Treatment Facilities in Southern Taiwan

The wastewater treatment plants (WWTPs) of three representative petrochemical plants in southern Taiwan were sampled to investigate their VOC emission characteristics. Generally, emissions decline along the process flow, while the VOC concentration accumulates to as much as around 2400 mg/m3 (as total hydrocarbons) at several closed vessel vents during the primary treatment. VOC emission rates (g/s) and fluxes (g/m2 hr) exhibit a similar trend of reducing concentrations in the WWTPs. From the field analysis data, VOC emission potential is best indicated by the concept of emission flux rather than concentration or emission rate. The Water 8 emission model version 4, developed by the U.S. EPA in 1995, was used to simulate the emission rate. The output results were compared to the calculated VOC liquid–gas mass equilibrium based essentially on the saturated gas concentration of the individual VOC components in wastewater. The comparisons clearly identified the proposed mass transfer approach using as a reliable timesaving alternative to Water 8, which requires numerous input parameters and water analysis data.