Volatile Organic Compounds Emission Factors Research Articles

Exhaust emissions of volatile organic compounds of powered two-wheelers: Effect of cold start and vehicle speed. Contribution to greenhouse effect and tropospheric ozone formation

Powered two-wheeler (PTW) vehicles complying with recent European type approval standards (stages Euro 2 and Euro 3) were tested on chassis dynamometer in order to measure exhaust emissions of about 25 volatile organic compounds (VOCs) in the range C1–C7, including carcinogenic compounds as benzene and 1,3-butadiene. The fleet consists of a moped (engine capacity≤50cm3) and three fuel injection motorcycles of different engine capacities (150, 300 and 400cm3). Different driving conditions were tested (US FPT cycle, constant speed). Due to the poor control of the combustion and catalyst efficiency, moped is the highest pollutant emitter. In fact, fuel injection strategy and three way catalyst with lambda sensor are able to reduce VOC motorcycles' emission of about one order of magnitude with respect to moped. Cold start effect, that is crucial for the assessment of actual emission of PTWs in urban areas, was significant: 30–51% of extra emission for methane. In the investigated speed range, moped showed a significant maximum of VOC emission factor at minimum speed (10km/h) and a slightly decreasing trend from 20 to 60km/h; motorcycles showed on the average a less significant peak at 10km/h, a minimum at 30–40km/h and then an increasing trend with a maximum emission factor at 90km/h. Carcinogenic VOCs show the same pattern of total VOCs. Ozone Formation Potential (OFP) was estimated by using Maximum Incremental Reactivity scale. The greatest contribution to tropospheric ozone formation comes from alkenes group which account for 50–80% to the total OFP. VOC contribution effect on greenhouse effect is negligible with respect to CO2 emitted.

Emission Factors from Aerial and Ground Measurements of Field and Laboratory Forest Burns in the Southeastern U.S.: PM2.5, Black and Brown Carbon, VOC, and PCDD/PCDF

Aerial- and ground-sampled emissions from three prescribed forest burns in the southeastern U.S. were compared to emissions from laboratory open burn tests using biomass from the same locations. A comprehensive array of emissions, including PM2.5, black carbon (BC), brown carbon (BrC), carbon dioxide (CO2), volatile organic compounds (VOCs), and polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) were sampled using ground-based and aerostat-lofted platforms for determination of emission factors. The PM2.5 emission factors ranged from 14 to 47 g/kg biomass, up to three times higher than previously published studies. The biomass type was the primary determinant of PM2.5, rather than whether the emission sample was gathered from the laboratory or the field and from aerial- or ground-based sampling. The BC and BrC emission factors ranged from 1.2 to 2.1 g/kg biomass and 1.0 to 1.4 g/kg biomass, respectively. A decrease in BC and BrC emission factors with decreased combustion efficiency was found from both field and laboratory data. VOC emission factors increased with decreased combustion efficiency. No apparent differences in averaged emission factors were observed between the field and laboratory for BC, BrC, and VOCs. The average PCDD/PCDF emission factors ranged from 0.06 to 4.6 ng TEQ/kg biomass.

Study on the characteristics of pollutant emission from floor adhesive formulated using red clay

Development of building materials has been actively underway using natural materials in order to improve indoor air quality. Among such natural materials, red clay has been frequently used for development of building materials. In this study, 138 different environment-friendly adhesives were analyzed, aiming at determining the performance of adhesives prepared using red clay. The emission factors of formaldehyde and total volatile organic compounds (TVOCs) were examined for adhesives that had acquired the environment-friendly building materials certification before comparing with the characteristics of emission from red clay containing adhesives. In order to analyze pollutant reduction performance of the red clay adhesive, we exposed the clays to pollutants of formaldehyde and volatile organic compounds (VOCs), and analyzed the emission reduction performance due to adsorption on the red clay. The analysis results demonstrated the emission reduction performance of formaldehyde. Lastly, we compared the pollutant emission factors from multilayer building materials using red clay adhesive and general materials. The comparison results showed low emission factors for formaldehyde and VOCs. These results can be used as the basic data on performance characteristics of red clay adhesive.

Investigation of speciated VOC in gasoline vehicular exhaust under ECE and EUDC test cycles

The emission factors and compositions of volatile organic compounds (VOC) in exhaust gas from in-use gasoline passenger cars were characterized using a chassis dynamometer. Three passenger cars were tested at the ECE and the EUDC drive cycles to represent both urban and suburban driving scenarios. Exhaust gas was collected in Summa canisters and analyzed by gas chromatography–mass spectrometry (GC–MS). Common gaseous emissions (CH4, NOx, CO, and CO2) were measured by an on-board monitoring system. The VOC emission factors of different cars ranged from 0.10 to 0.25gkm−1 at the ECE cycle, and 0.01–0.02gkm−1 at the EUDC cycle. A total of 57 individual VOC were detected in the exhaust gas, and the weight percentages were very consistent among the three cars. Ethylene (11.80wt.%), toluene (11.27wt.%), and benzene (8.83wt.%) were the most abundant VOC in exhaust gas. Aromatics (38.32%) dominated the low speed conditions (ECE), while alkanes (37.34%) were the major compounds at the high speed condition (EUDC). The total amount of alkenes did not change much between those two cycles, while ethylene is abundant in the ECE and EUDC cycles. Ozone formation potential (OFP) was calculated to estimate the ozone yield from VOC emissions by gasoline cars and the results showed that OFP of VOC emission at the ECE cycle was about ten times higher than that at the EUDC cycle.

Volatile Organic Compound Emission Factors from Road Traffic in a Highway Tunnel in the Tokyo Metropolitan Area in Japan

Volatile Organic Compound Emission Factors from Road Traffic in a Highway Tunnel in the Tokyo Metropolitan Area in Japan

Evaluation of formaldehyde and VOCs emission factors from paints in a small chamber: The effects of preconditioning time and coating weight

The aims of this study were to improve the emission test method for the 20L small chamber standardized in Korea using paints and to develop an optical test method for paints. The emission factors of the total volatile organic compounds (TVOC) and formaldehyde from oil-based paints, emulsion paints and water-dispersion paints coated at 300g/m2 and cured for 24 (48)h were determined using the 20L small chamber method. The emission factors of TVOC and formaldehyde from all paints under steady state conditions were determined after 7 days with 24 (48)h of curing. The Korean standards require that paints be measured and analyzed on the third day after a test. However, the emission factors of TVOC and formaldehyde from the paints only began to stabilize 7 days after installing the samples. Until now, the emission test results have been reported mainly as concentration vs. time or emission factor vs. time profiles of TVOC and formaldehyde. The emission factors of the target volatile organic compounds (VOCs) and aldehyde types were obtained under specific test conditions according to the different coating weights. For all target volatile organic compounds and aldehyde types examined, the paint coating weight had an effect on emission.

Effect of Wind Tunnel Air Velocity on VOC Flux from Standard Solutions and CAFO Manure/Wastewater

Researchers and practitioners have used wind tunnels and flux chambers to quantify the flux of volatile organic compounds (VOCs), ammonia, and hydrogen sulfide and estimate emission factors from animal feeding operations (AFOs) without accounting for effects of air velocity or sweep air flow rate. Laboratory experiments were conducted using a small rectangular wind tunnel (30.5 cm length, 15.2 cm width, 5.1 cm height). The objectives of the research were to (1) quantify the effect of wind velocity on VOC flux rates, (2) compare and contrast a two-film model with different wind speed corrections, and (3) provide insight into methods for either selecting appropriate wind tunnel velocities or conducting post-sampling wind velocity corrections to simulate field emission rates. Fluxes were measured on standard solutions and on manure/wastewater from beef cattle and dairy AFOs. Volumetric air exchange rates were varied between 0.6 and 44 exchanges per minute, corresponding to calculated longitudinal air velocities of 0.003 to 0.23 m s-1. Exhaust air was sampled using stainless steel sorbent tubes and analyzed for eleven volatile organic compounds comprised of seven volatile fatty acids (VFAs: acetic, propionic, isobutyric, butyric, isovaleric, valeric, and hexanoic) and four heavier molecular weight semivolatile organic compounds (sVOCs: phenol, p-cresol, indole, and skatole) using gas chromatography/mass spectrometry. Sulfur-containing VOCs were quantified using a portable total reduced sulfur meter. Flux rates for VOCs with small dimensionless Henry's law constants (i.e., those found at AFOs) increased with increasing air velocity. The two-film model with an experimentally derived reference gas-film transfer coefficient was found to reliably predict VOC flux at velocities between 0.003 and 0.23 m s-1. However, the two-film model did not reliably predict VOC flux with other air velocity correction formulae, an indication that flux is a function of wind tunnel geometry and turbulence factors, and not just average air velocity or sweep air flow rate. These results corroborate other studies that show that air velocity is a major factor affecting VOC fluxes from AFOs, verifying that an air velocity correction factor is required for estimating accurate VOC emission factors using wind tunnels and flux chambers.

Vehicular emission of volatile organic compounds (VOCs) from a tunnel study in Hong Kong

Abstract. Vehicle emissions of volatile organic compounds (VOCs) were determined at the Shing Mun Tunnel, Hong Kong in summer and winter of 2003. One hundred and ten VOCs were quantified in this study. The average concentration of the total measured VOCs at the inlet and outlet of the tunnel were 81 250 pptv and 117 850 pptv, respectively. Among the 110 compounds, ethene, ethyne and toluene were the most abundant species in the tunnel. The total measured VOC emission factors ranged from 67 mg veh−1 km−1 to 148 mg veh−1 km−1, with an average of 115 mg veh−1 km−1. The five most abundant VOCs observed in the tunnel were, in decreasing order, ethene, toluene, n-butane, propane and i-pentane. These five most abundant species contributed over 38% of the total measured VOCs emitted. The high propane and n-butane emissions were found to be associated with liquefied petroleum gas (LPG)-fueled taxis. Fair correlations were observed between marker species (ethene, i-pentane, n-nonane, and benzene, toluene, ethylbenzene and xylenes – BTEX) with fractions of gasoline-fueled or diesel-fueled vehicles. Moreover, ethene, ethyne, and propene are the key species that were abundant in the tunnel but not in gasoline vapors or LPG. The ozone formation potential from the VOCs in Hong Kong was evaluated by the maximum increment reactivity (MIR). It was found to be 568 mg of ozone per vehicle per kilometer traveled. Among them, ethene, propene and toluene contribute most to the ozone-formation reactivity.

Characteristics of gaseous pollutants from biofuel-stoves in rural China

The research team analyzed the emission characteristics of gaseous pollutants, including volatile organic compounds (VOCs), from biomass combustion in improved stoves in rural China. The research included measurements from five biofuels and two stove types in the months of January, April, and September. The measurements were conducted according to U.S. EPA Method 25 using a collection system with a cooling device and two-level filters. CO, CO 2, NO x , CH 4 and THC analyzers were used for in-field, real-time emission measurements. The emission data indicate that gaseous pollutants were emitted at higher concentrations in the early combustion stage and lower concentrations in the later stage. CH 4 and THC, as well as CO and CO 2, presented positive relationships during the whole entire combustion process for all tests. The chemical profiles of flue gas samples were analyzed by GC/MS and GC/FID/ECD. Aromatics, carbonyls, and alkenes & alkynes dominated the VOC emissions, respectively accounting for 37%, 33%, and 23% of total VOC emissions by volume. Benzene was the most abundant VOC species, consisting of 17.3 ± 8.1% of VOCs, followed by propylene (11.3 ± 3.5%), acetone (10.8 ± 8.2%), toluene (7.3 ± 5.7%) and acetaldehyde (6.5 ± 7.3%). Carbon mass balance approach was applied to calculate CO, CO 2, CH 4, NO x , and VOC species emission factors. This analysis includes a discussion of the differences among VOC emission factors of different biofuel-stove combinations.

In Situ, Fast-response, Molecular-selective Methods for Measuring Emission Factors of Volatile Organic Compounds (VOCs) into the Atmosphere

Abstract A sensitive, real-time, and molecular-selective analyzer using a resonance-enhanced multiphoton ionization/time-of-flight mass spectrometer (REMPI-TOFMS) was combined with the chamber method to measure emission factors of VOCs during painting. Temporal variation of VOC emission was successfully captured on site on a second time scale. Exact and detailed assessment of emission is realized with molecular-dependent characteristics considered.

MEASUREMENT OF VOLATILE ORGANIC COMPOUNDS EMISSION FACTORS FROM COATING MATERIALS BY USE OF A THREE LITERS CHAMBER

A 20 liters chamber which is standardized in JIS A 1901:2003 “Small chamber method - Determination of the emission of volatile organic compounds and aldehydes for building products” has been popularly used for measurement of volatile organic compounds (VOC) emission factors from coating materials. A 3 liters chamber which was newly developed for measurement of VOC emission factors from coating materials was evaluated and compared with the 20 liters chamber in the study. Air tightness, recovery and mass transfer coefficient of the 3 liters chamber were evaluated in accordance with JIS A 1901:2003. Further, correlation between VOC emission factors obtained by the 20 liters chamber method and the 3 liters chamber method was examined through measurement of acrylic enamel paint and a textured coating material.The results can be summarized as follows;1) Air tightness of the 3 liters chamber meets the requirement of ENV13419-1:1999 “Building products, Determination of the emission of volatile organic compounds - Part1: Emission test chamber method.”2) Recovery and mass transfer coefficient of the 3 liters chamber satisfy the requirements of JIS A 1901:2003.3) VOC emission factors obtained show high correlation between the 20 liters chamber method and the 3 liters chamber method.

Determination of Volatile Organic Profiles and Photochemical Potentials from Chemical Manufacture Process Vents

The main objective of this study was to monitor the volatile organic compounds (VOCs) in the stack gas released from organic chemical industrial plants to determine emission factors. Samples from 52 stacks, with or without air pollution control devices (APCDs), from seven industrial processes were taken and VOCs measured using U.S. Environmental Protection Agency (EPA) Method 18. These 7 processes, including 26 plants, were the manufacturers of acrylonitrile–butadiene–styrene (ABS), polyvinyl chloride (PVC), polystyrene (PS), acrylic resin (ACR), vinyl chloride (VC), para–terephthalic acid (PTA), and synthetic fiber (SYF). The results clearly indicate significant variations of emission factors among the various industrial processes, particularly emission factors for those without APCDs. As expected, those with APCDs yield much less emission factors. Regardless of those with or without APCDs, the order of manufacturing processes with regard to VOC emission factors is SYF > ABS > PS > ACR > PTA > PVC > VC. The emission factors for some processes also differ from those in EPA–42 data file. The VOC profiles further indicate that some VOCs are not listed in the U.S. VOC/Particulate Matter Speciation Data System (SPECIATE). The potential O3 formation is determined from the total amount of VOC emitted for each of seven processes. The resultant O3 yield varied from 0.22 (ACR) to 2.33 g O3 g–1 VOC (PTA). The significance of this O3 yield is discussed.

Emission Factors for Gas-Powered Vehicles Traveling Through Road Tunnels in São Paulo, Brazil

The objective of this study was to improve the vehicular emissions inventory for the light- and heavy-duty fleet in the metropolitan area of São Paulo (MASP), Brazil. To that end, we measured vehicle emissions in road tunnels located in the MASP. On March 22-26, 2004 and May 04-07, 2004, respectively, CO, CO2, NOx, SO2, and volatile organic compounds (VOCs) emissions were measured in two tunnels: the Janio Quadros, which carries light-dutyvehicles; and the Maria Maluf, which carries light-duty vehicles and heavy-duty diesel trucks. Pollutant concentrations were measured inside the tunnels, and background pollutant concentrations were measured outside of the tunnels. The mean CO and NOx emission factors (in g km(-1)) were, respectively, 14.6 +/- 2.3 and 1.6 +/- 0.3 for light-duty vehicles, compared with 20.6 +/- 4.7 and 22.3 +/- 9.8 for heavy-duty vehicles. The total VOCs emission factor for the Maria Maluf tunnel was 1.4 +/- 1.3 g km(-1). The main VOCs classes identified were aromatic, alkane, and aldehyde compounds. For the heavy-duty fleet, NOx emission factors were approximately 14 times higher than those found for the light-duty fleet. This was attributed to the high levels of NOx emissions from diesel vehicles.

Volatile organic compound emission factors from roadside measurements

Volatile organic compounds (VOCs) play a significant role in the generation of urban photochemical smog. In addition, some VOCs, such as benzene, are harmful to human health. In Japan, motor vehicles are the dominant source of VOCs. Therefore, it is important to determine the emission of VOCs from vehicles in order to estimate human risk and the production mechanisms of photochemical smog. In this study, we estimated emission factors with a methodology that considered the following points: (1) real-world emissions, (2) individual VOCs, (3) low vehicle speeds, (4) low investigation cost, and (5) user-friendly methodology. Samples were collected approximately 5 m from each side of National Route No. 467 in Kanagawa Prefecture, Japan. Sampling consisted of twelve 1-h sampling periods at three points on three dates: 21 February 2003 (7:00–19:00), 13 May 2003 (7:00–19:00), and 13 September 2003 (8:00–20:00). The samples were analyzed using GC/FID and GC/MS. In addition, information on vehicle types, traffic volumes, and weather conditions was collected from beside the road. Emission factors of individual VOCs were estimated from the measured data by running the CALINE4 dispersion model as an inverse model. The average speed of all vehicles was 22 km h −1; 81.3% of all vehicles were light-duty vehicles, 12.3% were heavy-duty vehicles, and 6.5% were motorcycles. We estimated the emission factors of 34 individual VOCs. The emission factors for all vehicles combined averaged over all sampling days ranged from 0.25 to 51 mg vehicle −1 km −1. The emission factors of benzene and toluene were 5.2 and 17 mg vehicle −1 km −1, respectively. In addition, the estimated emission factors were compared with those estimated from other recent studies. The emission factors for light-duty vehicles (LDVs), heavy-duty vehicles (HDVs), and motorcycles separately were also estimated by using a non-negative least squares method. However, these emission factors were found to be unreliable for the current sample size; therefore, the sample size needed to estimate reliable emission factors was calculated.

Gaseous and Particulate Emissions from Prescribed Burning in Georgia

Prescribed burning is a significant source of fine particulate matter (PM2.5) in the southeastern United States. However, limited data exist on the emission characteristics from this source. Various organic and inorganic compounds both in the gas and particle phase were measured in the emissions of prescribed burnings conducted at two pine-dominated forest areas in Georgia. The measurements of volatile organic compounds (VOCs) and PM2.5 allowed the determination of emission factors for the flaming and smoldering stages of prescribed burnings. The VOC emission factors from smoldering were distinctly higher than those from flaming except for ethene, ethyne, and organic nitrate compounds. VOC emission factors show that emissions of certain aromatic compounds and terpenes such as alpha and beta-pinenes, which are important precursors for secondary organic aerosol (SOA), are much higher from active prescribed burnings than from fireplace wood and laboratory open burning studies. Levoglucosan is the major particulate organic compound (POC) emitted for all these studies, though its emission relative to total organic carbon (mg/g OC) differs significantly. Furthermore, cholesterol, an important fingerprint for meat cooking, was observed only in our in situ study indicating a significant release from the soil and soil organisms during open burning. Source apportionment of ambient primary fine particulate OC measured at two urban receptor locations 20-25 km downwind yields 74 +/- 11% during and immediately after the burns using our new in situ profile. In comparison with the previous source profile from laboratory simulations, however, this OC contribution is on average 27 +/- 5% lower.

Travel Characteristics of Urban Freight Vehicles and Their Effects on Emission Factors

This study collected local commercial vehicle data in Knox County, Tennessee, from the U.S. Postal Service (USPS) and two companies engaged in package pickup and delivery (PUD). Another urban commercial vehicle data set with a wider spectrum of freight companies was obtained from North Carolina for comparative analysis. The two data sets were analyzed to develop two sets of values for input parameters for the U.S. Environmental Protection Agency's MOBILE6 model. Statistical tests permitted four aggregated vehicle usage classes to be formed. Two runs of MOBILE6 modeled the two commercial vehicle data sets in their entirety. Four additional runs modeled each vehicle usage class individually through the use of average speed and starts per day specific to the driving pattern of each class. Differences between the values of input parameters and emission factors based on data collected by this study and those based on the default values of MOBILE6 are discussed. Commercial vehicles examined by this study indicated higher annual mileage accumulation rates than the default values. Also their vehicle miles traveled and engine start distributions by hour of day varied considerably from the default values, occurring primarily between the two daily peak traffic periods (morning and evening). The study found higher volatile organic compounds (VOCs), carbon monoxide (CO), and nitrogen oxide emission factors than in default runs for USPS vehicles, whose driving pattern resulted in lower-than-default average speed. Higher VOC and CO emission factors were found for gasoline and diesel package PUD vehicles due to lower-than-default average speeds and higher-than-default starts per day.

Effect of outside air ventilation rate on volatile organic compound concentrations in a call center

Abstract A study of the relationship between outside air ventilation rate and concentrations of volatile organic compounds (VOCs) generated indoors was conducted in a call center office building. The building, with two floors and a total floor area of 4600 m 2 , is located in the San Francisco Bay Area, CA. Ventilation rates were manipulated with the building's four air handling units (AHUs). VOC and CO 2 concentrations in the AHU returns were measured on 7 days during a 13-week period. VOC emission factors were determined for individual zones on days when they were operating at near steady-state conditions. The emission factor data were subjected to principal component (PC) analysis to identify groups of co-varying compounds. Potential sources of the PC vectors were ascribed based on information from the literature. The per occupant CO 2 generation rates were 0.0068–0.0092 l s −1 . The per occupant isoprene generation rates of 0.2–0.3 mg h −1 were consistent with the value predicted by mass balance from breath concentration and exhalation rate. The relationships between indoor minus outdoor VOC concentrations and ventilation rate were qualitatively examined for eight VOCs. Of these, acetaldehyde and hexanal, which likely were associated with material sources, and decamethylcyclopentasiloxane, associated with personal care products, exhibited general trends of higher concentrations at lower ventilation rates. For other compounds, a clear inverse relationship between VOC concentrations and ventilation was not observed. The net concentration of 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate isomers, examples of low-volatility compounds, changed very little with ventilation likely due to sorption and re-emission effects. These results illustrate that the efficacy of ventilation for controlling VOC concentrations can vary considerably depending upon the operation of the building, the pollutant sources and the physical and chemical processes affecting the pollutants. Thus, source control measures, in addition to adequate ventilation, are required to limit concentrations of VOCs in office buildings.

Emission Characteristics of Volatile Organic Compounds from Semiconductor Manufacturing

A huge amount of volatile organic compounds (VOCs) is produced and emitted with waste gases from semiconductor manufacturing processes, such as cleaning, etching, and developing. VOC emissions from semiconductor factories located at Science-Based Industrial Park, Hsin-chu, Taiwan, were measured and characterized in this study. A total of nine typical semiconductor fabricators (fabs) were monitored over a 12-month period (October 2000-September 2001). A flame ionization analyzer was employed to measure the VOC emission rate continuously in a real-time fashion. The amount of chemical use was adopted from the data that were reported to the Environmental Protection Bureau in Hsin-chu County as per the regulation of the Taiwan Environmental Protection Administration. The VOC emission factor, defined as the emission rate (kg/month) divided by the amount of chemical use (L/month), was determined to be 0.038 ± 0.016 kg/L. A linear regression equation is proposed to fit the data with the correlation coefficient (R2) = 0.863. The emission profiles of VOCs, which were drawn using the gas chromatograph/mass spectrometer analysis method, show that isopropyl alcohol is the dominant compound in most of the fabs.

Assessment of the strategies for reducing volatile organic compound emissions in the automotive industry in Taiwan

Automotive coating processes must adhere to consumer preferences, such as anti-rust, weatherproof and overall appearance of coatings. Some solvents are added as thinners and additives to avoid excessive viscosity of the coating materials and to increase facility in painting. In addition, solvents use in the automotive industry in Taiwan is estimated at 7200 ton/year in major coating processes, including electrodeposition coating, primer coating, top coating, and bar coating. Volatile organic compounds (VOCs) are not easily controlled. It is important to know the VOC-pollution sources and emission characteristics before treating the VOCs in automobile industry. In this study, 80 stacks in five factories were tested to evaluate emission characteristics in each VOC-source. After examining the flue gases, the amount of solvents used for washing spray gun and base coating are estimated at 3350 ton/year, and about 1700 ton/year for primer coat and clear coat. The organic solvents include toluene, xylene, ethyl acetate, n-butyl acetate, and ketone. VOC emission factors from each plant ranges between 500 and 650 g-VOC/l coating. To reduce the amount of coating and waste liquor, recommended methods include increasing gun spray efficiency, lengthening the same color-painting period, reducing the solvent content in painting and adding treatment equipment. The high-solid content painting, waterborne coat, and powder coat should be used for traditional painting. Moreover, carbon adsorption bed and zeolite rotator recovery system can replace scrubbers, since they can be used as solvent recovery equipment.

Influence of road traffic on volatile organic compound concentrations in and above a deep Alpine valley

Volatile organic compounds (VOCs) were measured with a motor-glider during six days of July and August, 1996, in Switzerland’s Mesolcina valley. Morning and afternoon profiles from the motor-glider reached up to 4000 m above sea level (m asl). Additional measurements were made on the valley floor with the same type of instrument. The concentration differences at various altitudes between morning and afternoon were correlated with traffic emission factors for the individual VOCs. Traffic emissions govern the concentrations of anthropogenic VOCs in this Alpine valley and above the crests. Due to vertical transport of air, VOC concentrations can increase strongly during daytime at high altitudes (∼2000–4000 m asl) over the Alps.