HCHO Emission Research Articles

Determination of formaldehyde release from wood-based panels using SPME-GC-FAIMS

Several standardized methods exist to determine formaldehyde (HCHO) release from wood-based panels (WBPs). These methods were developed decades ago to be used in manufacturers laboratories to provide a mean of production control. They are robust and take several hours to yield results. Modern WBP panel production, however, is a continuous process. Therefore the established methods are too time-consuming for process control and process optimization with respect to HCHO release. Moreover, there is a strong trend of lowering the regulatory HCHO emission limits. Thus, there is a need for a comparatively fast and precise method which is suitable for the use on-site in a WBP manufacturers laboratory. In this work, an optimization of the solid phase micro extraction gas chromatography high field asymmetric waveform ion mobility spectrometry (SPME-GC-FAIMS) method is presented with respect to GC-FAIMS settings and the calibration procedure. It is also shown that, in addition to WBP block samples, also particles can be used for the measurement. The industrial applicability of SPME-GC-FAIMS system was demonstrated by testing the HCHO release of freshly produced WBPs on-site in the manufacturers laboratory.

Emission factor estimation in regional air quality studies of residential natural gas fuel interchangeability

Natural gas is a ubiquitous fuel, obtained from a variety of source deposits that present an inherent variation in composition. As newer sources of natural gas become available (such as Liquefied Natural Gas and shale gas) the compositional variation is expected to increase, which can affect emissions during combustion in appliances, including criteria pollutants. Unfortunately, experimental observations of the effect of natural gas composition on combustion products are sparse due to the wide range of burner designs and high cost of experimentation. The current work develops a rigorous methodology for statistical inference on available data that accounts for the limited nature of experimental observations. The goal is to overcome data size and quality limitations and provide best estimates of emission response to fuel composition change by identifying a continuous probability distribution with a high likelihood of representing the data and high correlation to the experimental observations. Quantitative measures of agreement between the data and a set of candidate distributions form the basis of the evaluation. In addition, qualitative assessment of the reliability of distribution identification is derived from a quantitative rating system for desired features of the data set and chosen distribution. Finally, this methodology is applied to sample data from the Lawrence Berkeley National Laboratory to develop a comprehensive and self-consistent set of emission factor estimates applicable to investigations of modeling the effect of natural gas interchangeability on urban air quality. By following the developed process, representative distributions, ranges of estimates, and evaluations of the estimate reliability are obtained for changes in CO, NOx, NO2, and HCHO emissions as a function of change in fuel Wobbe Number for six classifications of residential appliances.

BioArena System for Knowing and Understanding the Biological World: A Review with New Experimental Results

A simple observation is the basis of the development of BioArena system: according to the first observations during the biological incubation after inoculation there is formaldehyde (HCHO) emission from the chromatographic spots; in this emission process, the level of HCHO molecules decreases time dependently. In fact, the antibiotic effect of an antibiotic-like compound decreases in parallel with the HCHO emission. The investigations demonstrated clearly a unique function and role of endogenous HCHO and its one main reaction product, ozone (O3), in the antiproliferative (e.g., antimicrobial) effect of different molecules with diverse chemical structures. The results in BioArena can be extended for in vivo conditions (e.g., greenhouse experiments), as well. For the pretreatment with different doses of inducers (immunostimulation-inducing molecules) there are always four bioequivalent immunostimulating response ranges (quadruple bioequivalent immune response system) in plants. The inducers (e.g., N-methylated basic amino acids, salicylic acid, cinnamic acid, and trace elements) do not participate directly in the induction of the immunostimulating effect. These new findings support a statement that HCHO and its reaction products (mainly O3), as bioreactive small molecules, are responsible for the immunostimulating activity (in vivo conditions), as well.

Radical precursors and related species from traffic as observed and modeled at an urban highway junction

Nitrous acid (HONO) and formaldehyde (HCHO) are important precursors for radicals and are believed to favor ozone formation significantly. Traffic emission data for both compounds are scarce and mostly outdated. A better knowledge of today's HCHO and HONO emissions related to traffic is needed to refine air quality models. Here the authors report results from continuous ambient air measurements taken at a highway junction in Houston, Texas, from July 15 to October 15, 2009. The observational data were compared with emission estimates from currently available mobile emission models (MOBILE6; MOVES [MOtor Vehicle Emission Simulator]). Observations indicated a molar carbon monoxide (CO) versus nitrogen oxides (NOx) ratio of 6.01 ± 0.15 (r 2 = 0.91), which is in agreement with other field studies. Both MOBILE6 and MOVES overestimate this emission ratio by 92% and 24%, respectively. For HCHO/CO, an overall slope of 3.14 ± 0.14 g HCHO/kg CO was observed. Whereas MOBILE6 largely underestimates this ratio by 77%, MOVES calculates somewhat higher HCHO/CO ratios (1.87) than MOBILE6, but is still significantly lower than the observed ratio. MOVES shows high HCHO/CO ratios during the early morning hours due to heavy-duty diesel off-network emissions. The differences of the modeled CO/NOx and HCHO/CO ratios are largely due to higher NOx and HCHO emissions in MOVES (30% and 57%, respectively, increased from MOBILE6 for 2009), as CO emissions were about the same in both models. The observed HONO/NOx emission ratio is around 0.017 ± 0.0009 kg HONO/kg NOx which is twice as high as in MOVES. The observed NO2/NOx emission ratio is around 0.16 ± 0.01 kg NO2/kg NOx, which is a bit more than 50% higher than in MOVES. MOVES overestimates the CO/CO2 emission ratio by a factor of 3 compared with the observations, which is 0.0033 ± 0.0002 kg CO/kg CO2. This as well as CO/NOx overestimation is coming from light-duty gasoline vehicles. Implications: Nitrous acid (HONO) and formaldehyde (HCHO) are important precursors for radicals that ultimately contribute to ozone formation. There still exist uncertainties in emission sources of HONO and HCHO and thus regional air quality modeling still tend to underestimate concentrations of free radicals in the atmosphere. This paper demonstrates that the latest U.S. Environmental Protection Agency (EPA) traffic emission model MOVES still shows significant deviations from observed emission ratios, in particular underestimation of HCHO/CO and HONO/NOx ratios. Improving the performance of MOVES may improve regional air quality modeling.

Modified Nanocrystalline Cellulose Used for Improving Formaldehyde Emission and Bonding Strength of Urea Formaldehyde Resin Adhesive

Nanocrystalline cellulose (NCC) was used for improving the formaldehyde (HCHO) emission and bonding strength of urea formaldehyde (UF) resin adhesive in fiberboard and plywood. The original NCC was modified by 3-aminopropyltriethoxysilane (APTES) and the wetting property with UF resin adhesive was improved by 26.4%. The UF resin adhesive with modified NCC was characterized by X-ray powder diffraction (XRD), thermogravimetric analysis (TG) and Fourier transform infrared (FT-IR). The crystal region of UF resin adhesive was influenced by NCC and the diffraction intensity of the peak at 2θ = 22.82° was enhanced significantly. The thermal stability of UF resin adhesive with 1.0% modified NCC increased by 4.9%. And modified NCC led hydroxyl groups into the UF resin adhesive. HCHO emission and bonding strength of the UF resin adhesive with modified NCC were tested according to Chinese National Standards GB/T 17657-1999 and GB/T 9846-2004. The HCHO emission of fiberboard and plywood with 1.5% modified NCC decreased by 13.0% and 53.2%, respectively. The bonding strength of fiberboard increased by 158.3% (from 0.12 MPa of control group to 0.31 MPa of fiberboard with 1.5% modified NCC), while 1.5% modified NCC led to a 23.6% increase in the plywood.

Application of an adjoint neighborhood‐scale chemistry transport model to the attribution of primary formaldehyde at Lynchburg Ferry during TexAQS II

AbstractDuring the 2006 Second Texas Air Quality Study (TexAQS II) field study, ambient mixing ratios of formaldehyde (HCHO) up to 52 ppbv were observed at Lynchburg Ferry in the Houston Ship Channel on the morning of 27 September 2006. These elevated mixing ratios coincided with a flare event during a sequential planned shutdown of a petrochemical facility ~8 km from the monitoring site. An adjoint version of the Houston Advanced Research Center (HARC) neighborhood air quality model was used to perform 4‐D variational inverse modeling of industrial emissions of HCHO and other ozone precursors based on Lynchburg Ferry observations. The simulation employed a horizontal domain size and grid resolution of 8 km × 8 km and 400 m, and was conducted for a 1.5 h period (8–9:30 A.M.) during which the highest HCHO concentrations were recorded. The event emissions of ethene and propene computed by the inverse model are consistent with the largest estimated emissions for the facility in question derived from the Solar Occultation Flux technique during TexAQS II. Moreover, the computed peak flare emissions of HCHO during the shutdown event were around 282 kg/h, which is less than but comparable in magnitude to the largest area‐wide total (primary plus secondary) formaldehyde flux from the Houston Ship Channel measured by Differential Optical Absorption Spectroscopy during TexAQS II. The estimated flare event emissions of primary formaldehyde are roughly 50 times larger than HCHO emissions from flares used in routine operations, as inferred from remote sensing and/or real‐time in situ measurements during the 2009 SHARP campaign.

Formaldehyde concentration and its influencing factors in residential homes after decoration at Hangzhou, China

Air pollution surveys of formaldehyde (HCHO) were conducted in 2324 rooms decorated within one year in 2007–2009 in Hangzhou, China. The mean HCHO concentration (CHCHO) was 0.107 ± 0.095 mg/m3, and 38.9% of samples exceeded the Chinese National Standard GB 50325-2010. Over the past 3 years, the CHCHO decreased with time (p < 0.05). Relationships of potential factors to indoor CHCHO were also evaluated. CHCHO was related to temperature (T), relative humidity (RH), time duration of the windows and doors being closed before sampling (DC), time duration from the end of decoration to sampling (DR) and source characteristics (d). A model to relate indoor CHCHO to these five factors (T, RH, DC, DR, d) was established based on 298 samples (R2 = 0.87). Various factors contributed to CHCHO in the following order: T, 43.7%; d, 31.0%; DC, 10.2%; DR, 8.0%; RH, 7.0%; specifically, meteorological conditions (i.e., RH plus T) accounted for 50.7%. The coefficient of T and RH, RTH, was proposed to describe their combined influence on HCHO emission, which also had a linear relationship (R2 = 0.9387) with HCHO release in a simulation chamber test. In addition, experiments confirm that it is a synergistic action as T and RH accelerate the release of HCHO, and that is a significant factor influencing indoor HCHO pollution. These achievements could lead to reference values of measures for the efficient reduction of indoor HCHO pollution.

Particulate reinforcement and formaldehyde adsorption of modified nanocrystalline cellulose in urea-formaldehyde resin adhesive

In this study, nanocrystalline cellulose (NCC) was used for reinforcement and formaldehyde (HCHO) adsorption of urea-formaldehyde (UF) resin adhesive in fiberboard. The original NCC was modified by 3-aminopropyltriethoxysilane for improving the wetting property with UF resin adhesive. The UF resin adhesive with modified NCC was analyzed by X-ray powder diffraction, thermogravimetric analysis, and Fourier transform infrared. The HCHO emission and bending and bonding strength of the UF resin adhesive with modified NCC were tested according to Chinese National Standard GB/T 17657-1999. Compared with the original UF resin adhesive, modified NCC led to limited effects on the crystal structure, thermal stability, and characteristic absorption peaks of UF resin adhesive. The HCHO emission of the UF resin adhesive with 1.0% modified NCC decreased by 13.0%, while the bending and bonding strength increased by 40.5 and 158.3%, respectively. The improvements of modified UF resin adhesive were destroyed by the reunion of NCC when the content was more than 1.5%.

합판 공장 부산물을 이용한 파티클보드의 물성에 관한 연구 - 표층 구성요소 및 파티클 전처리 여부에 따른 비교 -

This study was performed to analyse cause of quality deterioration using byproduct of plywood and to determine physical and mechanical properties of particleboard used new bonding condition we found. The result of bending strength of Com-Ply board using EMDI is 57.7 on linear direction and 25.1 on vertical direction. EMDI has better water-resisting qualities than Urea formaldehyde adhesive according to result of thickness swelling and water absorption test. Pre-treatment soaked particle 72 hours in water caused increase of HCHO emission.

First direct measurements of formaldehyde flux via eddy covariance: implications for missing in-canopy formaldehyde sources

Abstract. We report the first observations of formaldehyde (HCHO) flux measured via eddy covariance, as well as HCHO concentrations and gradients, as observed by the Madison Fiber Laser-Induced Fluorescence Instrument during the BEACHON-ROCS 2010 campaign in a rural, Ponderosa Pine forest northwest of Colorado Springs, CO. A median noon upward flux of ~80 μg m−2 h−1 (~24 pptv m s−1) was observed with a noon range of 37 to 131 μg m−2 h−1. Enclosure experiments were performed to determine the HCHO branch (3.5 μg m-2 h−1) and soil (7.3 μg m−2 h−1) direct emission rates in the canopy. A zero-dimensional canopy box model, used to determine the apportionment of HCHO source and sink contributions to the flux, underpredicted the observed HCHO flux by a factor of 6. Simulated increases in concentrations of species similar to monoterpenes resulted in poor agreement with measurements, while simulated increases in direct HCHO emissions and/or concentrations of species similar to 2-methyl-3-buten-2-ol best improved model/measurement agreement. Given the typical diurnal variability of these BVOC emissions and direct HCHO emissions, this suggests that the source of the missing flux is a process with both a strong temperature and radiation dependence.

Modified nanocrystalline cellulose from two kinds of modifiers used for improving formaldehyde emission and bonding strength of urea-formaldehyde resin adhesive

In this study, nanocrystalline cellulose (NCC) was used for increasing the bonding strength of urea-formaldehyde (UF) resin adhesive, with a reduction of formaldehyde (HCHO) emissions. The surface of NCC was modified by 3-aminpropyltriethoxysilane (APTES) and 3-methacryloxypropyltrimethoxysilane (MPS) for the lack of compatibility with UF resin adhesive. The modified NCC was characterized by X-ray powder diffraction (XRD), thermogravimetric analysis (TG), and wetting property. HCHO emission and bonding strength of the UF resin adhesive with modified NCC were tested according to Chinese National Standards GB/T 17657-1999 and GB/T 9846-2004. The results of XRD, TG, and wetting property from NCC modified by APTES showed more significant improvements than that from NCC modified by MPS. The HCHO emission of UF resin adhesive with 1.5% NCC modified by APTES decreased by 53.2% and bonding strength increased by 23.6%, while the results from the NCC modified by MPS were 21.3% and 7.0%, respectively.

A Novel Approach of Chitosan Additive to Remove Formaldehyde from Building Materials

Formaldehyde (HCHO) which emitted from building materials, such as plywood and adhesive, is a carcinogenic substance in indoor air. Chitosan is produced from the structural element in the exoskeleton of crustaceans (such as crabs and shrimp), and has the ability to absorb HCHO. In this study, the HCHO removal efficiency by chitosan additives was evaluated for two building materials - adhesive and plywood. The experiments were performed in a small chamber based on the method of Japanese Industrial Standards (JIS) A1901 to evaluate the HCHO emission from adhesive and plywood before and after the application of chitosan additives. Both the HCHO concentration in the chamber and the HCHO emission factor of two adhesives, urea-formaldehyde (UF) resin and Poly Vinyl Acetate (PVAC) resin, were reduced from 0.02~0.21 ppm and 0.12~1.05 mg/m2h to 0~0.14 ppm and 0.12~0.63 mg/m2h after using chitosan additives. The best HCHO removal efficiency was adding 9% chitosan additives in the adhesives. The amount of absorbed HCHO is proportional to the amount of chitosan additives, and approximate 0.02 mg of HCHO can be absorbed by per mg of chitosan additive (i.e. absorption capacity 0.02 g HCHO/g Chitosan).

Biomass burning emission estimates inferred from satellite column measurements of HCHO: Sensitivity to co-emitted aerosol and injection height

[1] We infer monthly regional biomass burning emissions of formaldehyde (HCHO) during 2006 from space-borne column measurements of HCHO from the SCIAMACHY instrument over Canada, boreal Asia, South America, southern Africa, and Indonesia. We remove the influence of biogenic volatile organic compounds using an offline chemical mechanism. We quantify the sensitivity of our emission estimates to aerosol single scattering albedo, ω, indicative of fresh (ω = 0.8) and aged (ω > 0.9) aerosol, and the relative vertical distribution of the aerosol and HCHO, both which compromise the interpretation of space-based HCHO columns. For our control calculation we assume freshly-emitted gases and aerosols that are mainly confined to the boundary layer. Associated posterior emissions are generally lower than the prior emissions except over Canada and boreal Asia during northern hemisphere summer months. Accounting for faster vertical mixing results in posterior emissions 20%–100% higher than the corresponding control calculation, and consequently more consistent with the prior. Assuming an aged aerosol generally results in a 20% decrease in posterior emissions relative to prior values. Based on the range of posterior estimates from our sensitivity analyses, not accounting for uncertainties associated with the underlying gas-phase and heterogeneous chemistry, we estimate HCHO emission uncertainties are typically 20%–30% but can be up to 300% in extreme cases.

Potential of pulp and paper sludge as a formaldehyde scavenger agent in MDF resins

Abstract Sludge of pulp and paper mills have natural adhesive properties. The primary sludge (PS, contains fibers) and secondary sludge (SS, contains proteins) could also be suitable for manufacturing medium-density fiberboard (MDF). Protein in SS can react with formaldehyde (HCHO), and as an additive in urea-formaldehyde (UF) resins it can reduce formaldehyde emission. Thus, SS was investigated in the present study. PS and SS were collected from two mills and characterized in terms of chemical composition, fiber length distribution, pH, and buffering capacity. MDF samples were processed according to an experimental design, in which UF resin content was reduced from 12% to 8% and replaced by SS in the range of 5%–15%. Gel time measurement showed high SS reactivity with UF resin. The SS reduced HCHO emissions by up to 68% compared to control panels, without compromising internal bond strength. The bonding effect of SS was lower than expected due to the high pH, thus the buffering capacity reduced UF performance. Moreover, sludge reduced bending performance. Dimensional stability was the greatest disadvantage of sludge panels.

혈장변성접착제를 사용한 내수합판의 특성

This study was carried out to examine properties of water resistant plywood by using serum protein adhesive which is natural, environment-friendly and human-friendly. For the preparation of the serum protein adhesive, pig blood from slaughterhouse was centrifuged and serum was separated from corpuscles and concentrated to 30% by dry weight basis. This concentrated serum protein was modified with PF resin (50% NVC) with the ratio of 9 : 2.5. Plywood made by this modified serum protein gave 1.21 N/<TEX>$mm^2$</TEX> of dry bonding strength, 0.80 N/<TEX>$mm^2$</TEX> of wet boil bonding strength, 0% of cyclic delamination test value, and 0.025 ppm of HCHO emission, which met the excellent super <TEX>$E_0$</TEX> grade and water resistant plywood.

Source identification and budget analysis on elevated levels of formaldehyde within the ship plumes: a ship-plume photochemical/dynamic model analysis

Abstract. Elevated levels of formaldehyde (HCHO) along the ship corridors have been observed by satellite sensors, such as ESA/ERS-2 GOME (Global Ozone Monitoring Experiment), and were also simulated by global 3-D chemistry-transport models. In this study, three likely sources of the elevated HCHO levels in the ship plumes as well as their contributions to the elevated HCHO levels (budget) were investigated using a newly-developed ship-plume photochemical/dynamic model: (1) primary HCHO emission from ships; (2) secondary HCHO production via the atmospheric oxidation of non-methane volatile organic compounds (NMVOCs) emitted from ships; and (3) atmospheric oxidation of CH4 within the ship plumes. For this ship-plume modelling study, the ITCT 2K2 (Intercontinental Transport and Chemical Transformation 2002) ship-plume experiment, which was carried out about 100 km off the coast of California on 8 May 2002 (11:00 local standard time), was chosen as a base study case because it is the best defined in terms of (1) meteorological data, (2) in-plume chemical composition, and (3) background chemical composition. From multiple ship-plume model simulations for the ITCT 2K2 ship-plume experiment case, CH4 oxidation by elevated levels of in-plume OH radicals was found to be the main factor responsible for the elevated levels of HCHO in the ITCT 2K2 ship-plume. More than ~88% of the HCHO for the ITCT 2K2 ship-plume is produced by this atmospheric chemical process, except in the areas close to the ship stacks where the main source of the elevated HCHO levels would be primary HCHO from the ships (due to the deactivation of CH4 oxidation from the depletion of in-plume OH radicals). Because of active CH4 oxidation by OH radicals, the instantaneous chemical lifetime of CH4 (τCH4) decreased to ~0.45 yr inside the ship plume, which is in contrast to τCH4 of ~1.1 yr in the background (up to ~41% decrease) for the ITCT 2K2 ship-plume case. A variety of likely ship-plume situations at three different latitudinal locations within the global ship corridors was also studied to determine the enhancements in the HCHO levels in the marine boundary layer (MBL) influenced by ship emissions. It was found that the ship-plume HCHO levels could be 19.9–424.9 pptv higher than the background HCHO levels depending on the latitudinal locations of the ship plumes (i.e., intensity of solar radiation and temperature), MBL stability and NOx emission rates. On the other hand, NMVOC emissions from ships were not found to be a primary source of photochemical HCHO production inside ship plumes due to their rapid and individual dilution. However, the diluted NMVOCs would contribute to the HCHO productions in the background air.

Formaldehyde and its relation to CO, PAN, and SO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; in the Houston-Galveston airshed

Abstract. The Houston-Galveston Airshed (HGA) is one of the major metropolitan areas in the US that is classified as a nonattainment area of federal ozone standards. Formaldehyde (HCHO) is a key species in understanding ozone related air pollution; some of the highest HCHO concentrations in North America have been reported for the HGA. We report on HCHO measurements in the HGA from summer 2006. Among several sites, maximum HCHO mixing ratios were observed in the Houston Ship Channel (HSC), a region with a very high density of industrial/petrochemical operations. HCHO levels at the Moody Tower (MT) site close to downtown were dependent on the wind direction: southerly maritime winds brought in background levels (0.5–1 ppbv) while trajectories originating in the HSC resulted in high HCHO (up to 31.5 ppbv). Based on the best multiparametric linear regression model fit, the HCHO levels at the MT site can be accounted for as follows: 38.5±12.3% from primary vehicular emissions (using CO as an index of vehicular emission), 24.1±17.7% formed photochemically (using peroxyacetic nitric anhydride (PAN) as an index of photochemical activity) and 8.9±11.2% from industrial emissions (using SO2 as an index of industrial emissions). The balance 28.5±12.7% constituted the residual which cannot be easily ascribed to the above categories and/or which is transported into the HGA. The CO related HCHO fraction is dominant during the morning rush hour (06:00–09:00 h, all times are given in CDT); on a carbon basis, HCHO emissions are up to 0.7% of the CO emissions. The SO2 related HCHO fraction is significant between 09:00–12:00 h. After 12:00 h HCHO is largely formed through secondary processes. The HCHO/PAN ratios are dependent on the SO2 levels. The SO2 related HCHO fraction at the downtown site originates in the ship channel. Aside from traffic-related primary HCHO emissions, HCHO of industrial origin serves as an appreciable source for OH in the morning.

Aldehydes and Methanol Emission Mechanisms and Characteristics from a Methanol/Gasoline-Fueled Spark-Ignition (SI) Engine

Formaldehyde (HCHO), acetaldehyde (CH3CHO), and methanol (CH3OH) emission characteristics as well as their conversion efficiencies on the three-way catalytic converter (TWC) were investigated on a three-cylinder, spark-ignition (SI) engine when it ran on gasoline and M85 (gasoline/methanol = 15:85), respectively. In addition, their emission mechanisms were simulated on a plug flow reactor (PFR) model with the detailed kinetic mechanism of primary reference fuels as well. Simulation results show that there exist contribution zones for both HCHO and CH3CHO emissions in pipes along with decrescent temperatures; it contains two subzones of the generation zone (ZG) and the following generation−consumption zone (ZG−C). Aldehydes emissions become the peak value at the critical point, and the critical temperature of HCHO is higher than that of CH3CHO. The increase of the initial temperature and residence time of the gases in the pipe will move the aldehydes emissions from ZG to ZG−C along the emission profiles. The initial temperature of the exhaust pipe lies between the critical temperatures of HCHO and CH3CHO; thus, the HCHO emission decreases while the CH3CHO emission increases with the increase of the engine torque, i.e., initial temperature. With the increase of the engine speed, the decrease of the residence time takes the dominant role, the HCHO emission increases, while the CH3CHO emission decreases. However, the initial temperature in TWC is higher than the critical temperature of CH3CHO; the aldehydes conversion efficiencies decrease; and minus efficiencies appear at high engine speeds. Simulation results coincide well with the emission characteristics.

Formaldehyde and Methanol Emissions from a Methanol/Gasoline-Fueled Spark-Ignition (SI) Engine

With a three-cylinder spark-ignition (SI) engine, formaldehyde (HCHO) and methanol (CH3OH) emission characteristics as well as the three-way catalytic converter (TWC) conversion efficiency were investigated when it ran on gasoline, M10, M20, and M85 (gasoline blended with 10, 20, and 85% of methanol in volume), respectively. HCHO and CH3OH were detected by gas chromatography (GC) with a pulsed discharge helium ionization detector (PDHID). Experimental results show that HCHO emission increases with engine speed, while CH3OH emission from a methanol/gasoline blend-fueled engine decreases with it. HCHO emission from a gasoline-fueled engine varies in a “U” curve with the engine torque. The addition of 10% methanol in gasoline doubles the HCHO emission. The increasing methanol fraction greatly improves HCHO and CH3OH emission; their concentrations are both approximately linear to the amount of cyclically supplied fuel methanol. CH3OH can be totally removed by lightened-off TWC. However, the HCHO concentration may increase rather than decrease via the conversion of TWC at high engine speeds.

Comparison of emissions from on-road sources using a mobile laboratory under various driving and operational sampling modes

Abstract. Mobile sources produce a significant fraction of the total anthropogenic emissions burden in large cities and have harmful effects on air quality at multiple spatial scales. Mobile emissions are intrinsically difficult to estimate due to the large number of parameters affecting the emissions variability within and across vehicles types. The MCMA-2003 Campaign in Mexico City has showed the utility of using a mobile laboratory to sample and characterize specific classes of motor vehicles to better quantify their emissions characteristics as a function of their driving cycles. The technique clearly identifies "high emitter" vehicles via individual exhaust plumes, and also provides fleet average emission rates. We have applied this technique to Mexicali during the Border Ozone Reduction and Air Quality Improvement Program (BORAQIP) for the Mexicali-Imperial Valley in 2005. We analyze the variability of measured emission ratios for emitted NOx, CO, specific VOCs, NH3, and some primary fine particle components and properties by deploying a mobile laboratory in roadside stationary sampling, chase and fleet average operational sampling modes. The measurements reflect various driving modes characteristic of the urban fleets. The observed variability for all measured gases and particle emission ratios is greater for the chase and roadside stationary sampling than for fleet average measurements. The fleet average sampling mode captured the effects of traffic conditions on the measured on-road emission ratios, allowing the use of fuel-based emission ratios to assess the validity of traditional "bottom-up" emissions inventories. Using the measured on-road emission ratios, we estimate CO and NOx mobile emissions of 175±62 and 10.4±1.3 metric tons/day, respectively, for the gasoline vehicle fleet in Mexicali. Comparisons with similar on-road emissions data from Mexico City indicated that fleet average NO emission ratios were around 20% higher in Mexicali than in Mexico City whereas HCHO and NH3 emission ratios were higher by a factor of 2 in Mexico City than in Mexicali. Acetaldehyde emission ratios did not differ significantly whereas selected aromatics VOCs emissions were similar or smaller in Mexicali. Nitrogen oxides emissions for on-road heavy-duty diesel truck (HDDT) were measured near Austin, Texas, as well as in both Mexican cities, with NOy emission ratios in Austin &lt; Mexico City &lt; Mexicali.