Emission Fingerprints Research Articles

Characterizing anthropogenic methane sources in the Houston and Barnett Shale areas of Texas using the isotopic signature δ13C in CH4

Methane (CH4) is an important greenhouse gas with its mixing ratio increasing in the global atmosphere. Identifying fingerprints of CH4 emissions is critical to understanding potential impacts of various anthropogenic sources in the Greater Houston area (GHA) and extensive natural gas operations in the Barnett Shale area (BSA) of Texas. Stable carbon isotope ratios of CH4 (δ13CCH4) has been proposed to be a useful technique for differentiating individual CH4 sources. Measurements of CH4 mixing ratios and δ13CCH4 were sampled using a mobile laboratory equipped with cavity ring-down spectrometers (CRDS). Areal CH4 distributions and the background δ13CCH4 signature were obtained from filtered ambient signals; −47.0‰ (GHA) and − 48.5‰ (BSA) were calculated. The fingerprint of thirty-three anthropogenic sources in the two study areas were sampled with forty-four δ13C analyses conducted. Repeated measurements indicated the natural variation of δ13CCH4 signatures of individual CH4 sources. An unexpected massive CH4 fugitive leak was detected near the San Jacinto River Fleet site in Houston exhibiting an δ13CCH4 value around −42‰. Our results and findings demonstrate the utility of δ13CCH4for facilitating emission inventories and atmospheric modeling.

Carbazole‐Terpyridine Donor‐Acceptor Dyads with Rigid π‐Conjugated Bridges

A series of molecules in which 9H-carbazole (electron donor, D) and 2,2':6',2''-terpyridine (electron acceptor, A) are connected through rigid π-conjugated bridges (D-π-A systems) have been synthesized and their photophysical properties examined in detail, with the support of DFT calculations. The bridges are made of different sequences of ethynylene, phenylene, and anthracene groups. The synthetic strategies involve condensation of 2-acetylpyridine with the aromatic aldehyde moiety on different functionalized π-conjugated bridges and couplings with carbazole derivatives. The system incorporating anthracene in the bridge shows the typical absorption and emission fingerprints of this polycyclic hydrocarbon. The other systems have HOMOs and LUMOs centred, respectively, over the carbazole and the bridge and exhibit solvatochromic charge-transfer (CT) luminescence with high photoluminescence yield up to 70 %, except when an ethynylene unit is directly attached to the carbazole ring, due to a trans-bent non-emissive π-σ* excited state.

Spectroscopic characteristics of Hα/OI atomic lines generated by nanosecond pulsed corona-like discharge in deionized water

Basic emission fingerprints of nanosecond discharges produced in deionized water by fast rise-time positive high-voltage pulses (duration of 6 ns and amplitude of +100 kV) in a point-to-plane electrode geometry were investigated by means of time-resolved intensified charge-coupled device (ICCD) spectroscopy. Time-resolved emission spectra were measured via ICCD kinetic series during the discharge ignition and later phases over the 350–850 nm spectral range with fixed, either 3 ns or 30 ns, acquisition time and with 3 ns or 30 ns time resolution, respectively. The luminous phase of the initial discharge expansion and its subsequent collapse was characterized by a broadband vis-NIR continuum emission evolving during the first few nanoseconds which shifted more toward the UV with further increase of time. After ~30 ns from the discharge onset, the continuum gradually disappeared followed by the emission of Hα and OI atomic lines. The electron densities calculated from the Hα profile fit were estimated to be of the order of 1018–1019 cm−3. It is unknown if the Hα and OI atomic lines are generated even in earlier times (before ~30 ns) because such signals were not detectable due to the superposition with the strong continuum. However, subsequent events caused by the reflected HV pulses were observed to have significant effects on the emission spectra profiles of the nanosecond discharge. By varying the time delay of the reflected pulse from 45 to 90 ns after the primary pulse, the intensities of the Hα/OI atomic lines in the emission spectra of the secondary discharges were clearly visible and their intensities were greater with shorter time delay between primary and reflected pulses. These results indicate that the discharges generated due to the reflected pulses were very likely generated in the non-relaxed environment.

Luminous phase of nanosecond discharge in deionized water: morphology, propagation velocity and optical emission

We employed the techniques of time-resolved intensified charge-coupled device (ICCD) microscopy and spectroscopy to register basic morphologic and emission fingerprints of micro-discharges produced in deionized water. Fast rise-time positive high-voltage pulses (full width at half maximum of ∼7 ns and amplitude of ∼100 kV) in a point-to-plane electrode geometry produced micro-discharges, either periodically or in a single-pulse regime with the energy of ∼0.1 J dissipated during a single discharge event. Time resolved ICCD images evidence typical streamer-like branched filamentary morphology. Luminous discharge filaments show very fast and approximately linear initial expansion of the length with propagation velocity of ∼2 × 105 m s−1. When the HV pulse reaches its maximum value, the length of the primary luminous filaments reaches ∼1.3 mm. After initial expansion, the length of luminous filaments collapses and can be characterised by velocity of ∼1.9 × 104 m s−1. The first collapse is followed by a second slightly slower expansion, which is driven by the arrival of a reflected HV pulse, and which can be roughly approximated by propagation velocity of ∼1.5 × 105 m s−1. The second collapse (occurring after second expansion) proceeds at a nearly identical velocity compared with the first one. By combining two ICCD based techniques, we have been able to associate, for the first time ever, characteristic emission spectra with the most important phases of the micro-discharge development. The UV–vis-NIR emission spectra show a broad-band continuum evolving during the first expansion and collapse, followed by the well-known HI/OI atomic lines occurring together with continuum emission during the second expansion and collapse. We conclude that bound–free and free–free radiative transitions are basic emission characteristics of the nanosecond discharge initiation mechanism in liquid water which does not involve the formation of vapour bubbles.

δ15N values of atmospheric N species simultaneously collected using sector-based samplers distant from sources – Isotopic inheritance and fractionation

The nitrogen isotope ratios (δ15N) of atmospheric N species are commonly suggested as indicators of N emission sources. Therefore, numerous research studies have developed analytical methodologies and characterized primary (gases) and secondary emission products (mostly precipitation and aerosols) from various emitters. These previous studies have generally collected either reduced or oxidized N forms, and sampled them separately prior to determining their δ15N values. Distinctive isotopic signals have been reported for emissions from various sources, and seasonality of the δ15N values has been frequently attributed to shifts in relative contributions from sources with different isotopic signals. However, theoretical concepts suggest that temperature effects on isotopic fractionation may also affect the δ15N values of atmospheric reaction products.Here we use a sector-based multi-stage filter system to simultaneously collect seven reduced and oxidized N species downwind from five different source types in Alberta, Canada. We report δ15N values obtained with a state-of-the-art gold-furnace pre-concentrator online with an isotope ratio mass spectrometer (IRMS) to provide representative results even for oxidized-N forms. We find that equilibrium isotope effects and their temperature dependence play significant roles in determining the δ15N values of the secondary emission products. In the end, seasonal δ15N changes here are mainly caused by temperature effects on fractionation, and the δ15N values of only two N species from one source type can be retained as potential fingerprints of emissions.

Tailoring the Composition of Eu3+-Doped Y3NbO7 Niobate: Structural Features and Luminescent Properties Induced by Spark Plasma Sintering.

The defective fluorite-related Y3NbO7 host lattice was doped with Eu3+ ions to understand the influence of spark plasma sintering (SPS) process on this host lattice. The intrinsic disorder due to the occurrence of oxygen vacancies results in amorphous-type responses of the luminescent cations, and the spectral distribution varies as a function of the niobium content. Two spectral fingerprints of europium emissions were clearly enhanced. The correlation between luminescence, X-ray diffraction, and electron diffraction characterizations shows the existence of local inhomogeneity. Indeed, the particular nonequilibrium sintering conditions allowed pointing out a lack of miscibility within the Y3NbO7 solid solution domain. Thus, the SPS pellet is a composite of two extreme compositions. This phase demixing is mainly induced by the pressure coupled with a current effect that makes possible ionic migration in this Y3NbO7 ionic conductive matrix.

Effect of surface coating of KYb2F7:Tm3+ on optical properties and biomedical applications

This project aims to provide an insight on the effects of biocompatible polymers on the optical properties and the nanoparticle-cell interaction of KYb2F7:Tm3+ nanocrystals that exhibit strong near infrared (NIR) fluorescence. KYb2F7:Tm3+ nanocrystals were synthesized with a diameter of 20–30 nm and surface modified with poly(ethylene glycol), Pluronic® F-127, and poly(N-vinylpyrrolidone), due to the associated advantages. Some of these include biocompatibility and biodistribution in the instance of agglomeration and hydrophobicity as well as the addition of a targeting agent and drug loading by further functionalization. Despite the decrease in fluorescence intensity induced by the surface modification, thulium’s emission fingerprint was easily detected. Moreover, surface modified KYb2F7:Tm3+ nanocrystals failed to induce a toxic response on endothelial cells following a 24 h uptake period up to concentrations of 100 μg ml−1. In vitro toxicity and confocal imaging have demonstrated the versatility of these NIR fluorescence nanocrystals in biomedical imaging, drug delivery, and photodynamic therapy.

A laser-scanning confocal microscopy study of carrageenan in red algae from seaweed farms near the Caribbean entrance of the Panama Canal

Kappaphycus alvarezii (Doty) Doty ex P.C. Silva, a red macroalga, is a commercial source of carrageenan, a widely used polysaccharide compound important in the food and pharmaceutical industries, in nanotechnology, and in pharmacological applications. Carrageenan is found mainly in the cell wall and in the intercellular matrix. This is the first study to propose the characterization of carrageenans in vitro, using the auto-fluorescence properties of the alga treated with different polyamines: putrescine, spermidine, and spermine. This study suggests a four-phase cultivation sequence for seaweed farmers to enhance and assess the potential carrageenan yield of their crops. In phase 1, seedlings were treated with each of the polyamines. Explants were subsequently transferred through two additional culture phases before being planted on the sea farms in phase 4 and then harvested after 60 days for analysis. Images from transverse sections of 11 representative cultured K. alvarezii samples were obtained at 561 nm excitation wavelength for both the cell center and the cell wall of each sample. Spectral data were also analyzed using the spectral phasor algorithm of SimFCS developed at the Laboratory for Fluorescence Dynamics ( www.lfd.uci.edu ). We report on the identification of several spectral fluorescence emission fingerprints from different auto-fluorescence compounds spatially mapped using this technique. These fingerprints have the potential to improve strain selection of explants for enhanced carrageenan yield in seaweed farming operations as well as to enable wholesale pricing to correspond with crop quality.

Emission fingerprint of inland navigation vessels compared with road traffic, domestic heating and ocean going vessels

Despite increasing need for cargo shipping, little knowledge exists on emissions from inland navigation. Here we characterized and compared patterns of metals, and parent-, thio- and alkylated PAHs in gaseous and particulate emissions from inland navigation vessels (INVs) with those of road traffic, domestic heating (solid fuels) and ocean going vessels (OGVs) using data from this study and the literature. Diagnostic tools for tracing the environmental impact of inland navigation are proposed. INV and diesel fueled road traffic emissions were differentiated from OGVs and coal combustion via V/Ni values. The PAH inventory of particulate INV emissions also differed significantly from other emitters via a higher proportion of three ring PAHs. The ratio of phenanthrene to dibenzothiophene distinguished diesel fueled road traffic, lignite combustion, OGVs and INVs from gasoline fueled road traffic and wood combustion. The 1,7/(1,7+2,6) and 1,7/(1,7+x4) dimethylphenanthrene ratios (x4=sum of 1,3-, 2,10-, 3,9- and 3,10-dimethylphenanthrene) separated INV, road traffic (diesel), domestic heating and OGV emissions and are recommended for future application in environmental quality studies.

The black rock coatings in Rouyn-Noranda, Québec: fingerprints of historical smelter emissions and the local ore

Smelting of base metal sulfide rich ore in Rouyn-Noranda, Québec, has led to the formation of black rock coatings on exposed rocks to a maximum distance of 6 km from the smelter centre. This study has shown that these coatings are excellent mineralogical and chemical fingerprints of smelter emissions, ore types, and elemental partitioning into mineral phases. The black coatings are composed of a silica-rich matrix that formed due to the intense chemical weathering of exposed silicate rocks interacting with acidic meteoric waters. They contain metal sulfate rich layers along the atmosphere-coating interface (ACI) and rock-coating interface (RCI) formed by the in situ dissolution and precipitation of metal(loid)-bearing phases. Entombed within the silica matrix are spherical particulates and particles composed of Cu- and Zn-bearing Fe oxides (e.g., spinels), Fe oxides (e.g., hematite), Pb silicates (e.g., alamosite), sulfates (anglesite (PbSO4) and minerals of the jarosite group), amphiboles, pyroxenes, micas, Na feldspar, and clinochlore. Concentrations of elements are low in proximity to the smelter but drastically increase ∼2 km from the stack, most likely the result of a shadow effect of the smelter. This shadow effect is more pronounced if an element is highly compatible with minerals of the jarosite and spinel groups; it is called the smelter-compatibility effect. Elements displaying a high smelter-compatibility effect are Ag, Cu, Se, and As, whereas elements such as Hg, which is incompatible with the jarosite and spinel groups, show a low smelter-compatibility effect. High δ34S (5.5‰) values in proximity to the smelter and their decrease with distance is the result of mixing processes between primary and secondary sulfates in the atmosphere. The relative enrichments of metal(loid)s in coatings at Rouyn-Noranda and Sudbury, Ontario, when normalised to the MUd standard from Queensland, Australia, (MUQ) reflect the composition of the smelter emissions, ore, and lithologies. Black rock coatings of the Rouyn-Noranda and Sudbury study areas are enriched, for example, in Pb and Fe, respectively, reflecting higher abundances of galena and Fe-bearing minerals in the respective ore, emissions, and rocks in the region.

Emission Fingerprint Relationships of Low‐Level Water in Organic Solvents Based on Ln3+‐β‐Diketonate Complexes in Laponite

Detection of low‐content water in organic solvents is highly desirable for a number of chemical industries. However, most of luminescence water detectors reported so far easily generate liquid waste and the luminescence intensity of single emissive transition is susceptible by many factors. Herein a simple and green solid‐state detecting way is proposed to achieve the ratiometric detection of low‐level water in organic solvents based on Eu3+, Tb3+, and acac co‐doped Laponite (abbreviated as Eu1Tb9(acac)n@Lap). Such a luminescence detector represents excellent fingerprint correlation between water content in solvents and emission intensity ratio (IEu/ITb), and the variable emissive light colors of Eu1Tb9(acac)n@Lap is observed as water concentration in common organic solvents (MeCN, EtOH, and THF) increases (0%–5% v/v) clearly and directly with the naked eye. The approach should be a very promising strategy to achieve the low‐content water detecting in organic solvents.

Comparative analysis of cyanobacteria inhabiting rocks with different light transmittance in the Mojave Desert: a Mars terrestrial analogue

AbstractThe Mojave Desert has been long considered a suitable terrestrial analogue to Mars in many geological and astrobiological aspects. The Silver Lake region in the Mojave Desert hosts several different rock types (talc, marble, quartz, white carbonate and red-coated carbonate) colonized by hypoliths within a few kilometres. This provides an opportunity to investigate the effect of rock type on hypolithic colonization in a given environment. Transmission measurements from 300 to 800 nm showed that the transmission of blue and UVA varied between rock types. The wavelength at which the transmission fell to 1% of the transmission at 600 nm was 475 nm for white carbonate and quartz, 425 nm for red-coated carbonate and talc and 380 nm for marble. The comparative analysis of the cyanobacterial component of hypoliths under different rocks, as revealed by sequencing 16S rRNA gene clone libraries, showed no significant variation with rock type; hypoliths were dominated by phylotypes of the genusChroococcidiopsis, although less abundant phylotypes of the genusLoriellopsis, LeptolyngbyaandScytonemaoccurred. The comparison of the confocal laser scanning microscopy-λ (CLSM-λ) scan analysis of the spectral emission of the photosynthetic pigments ofChroococcidiopsisin different rocks with the spectrum of isolatedChroococcidiopsissp. 029, revealed a 10 nm red shift in the emission fingerprinting for quartz and carbonate and a 5 nm red shift for talc samples. This result reflects the versatility ofChroococcidiopsisin inhabiting dry niches with different light availability for photosynthesis.

Sequence-Specific Synthesis of Platinum-Conjugated Trichromophoric Energy Cascades of Anthracene, Tetracene, and Pentacene and Fluorescent “Black Chromophores”

A sequence-specific synthesis of trichromophoric energy cascades containing anthracenyl (A), tetracenyl (T), or pentacenyl (P) rings is achieved by coupling PtII ions and singly desilylated bis(triisopropylsilylethynyl)acenes (acene = anthracene, tetracene, or pentacene). Four sequences, T-P-T, P-T-P, A-P-T, and A-T-P, are generated. Absorption spectra of the triads show intense bands due to the S0 → S1 transitions of the acenes. The A-P-T and A-T-P, being able to absorb strongly throughout the entire visible region, are rare examples of “black chromophores”. Different sequences are shown to have different emission fingerprints. Emission spectra of A-P-T and A-T-P show that excitation at the S0 → S1 band of A gives rise to emissions from the S1 excited states of A, T, and P, implying the presence of energy transfer from the excited state of A to those of T and P.

Atmosphere's emission fingerprint affected by how clouds are stacked

Clouds, which can absorb or reflect incoming radiation and affect the amount of radiation escaping from Earth's atmosphere, remain the greatest source of uncertainty in global climate modeling.

In Vivo Skin Solvent Penetration Measurements Using Opto-thermal Radiometry and Fingerprint Sensor

This latest study on in vivo transdermal drug delivery by using opto-thermal radiometry and a capacitance-based fingerprint sensor is presented. A small amount of solvent was applied on the test sites of a volar forearm for a few minutes; opto-thermal measurements and fingerprint sensor measurements were performed both before the solvent application and periodically after. The results showed that, by selecting different detection wavelengths, opto-thermal radiometry could give the information either on the water concentration within skin or the solvent concentration within skin. The capacitance-based fingerprint sensor could clearly visualize solvent penetration through in vivo human skin, as it generated dynamic two-dimensional (2D) images of solvent distribution within skin, and combining with tape stripping, it was also possible to get solvent 3D depth profiles within skin. The correlation between opto-thermal transient emission radiometry and fingerprint sensor measurements was also evaluated.

MULTISPECTRAL CONCURRENT DETECTION OF MULTIPLE PROTEINS

Proteins constitutively function within networks. Concurrent detection of multiple proteins is crucial to clinical diagnoses and multidimensional drug profiling. Fluorescence microscopy is capable of multicolor imaging, and has the capability to quantify essentially any physiological changes that occur at the single-cell level and in the context of live single cells, and thus provides an alternative to flow cytometry for multiplexed live single-cell assay. The staining of cells with multiple labels is still a technical challenge while multiplexed assays are complicated by spectral emission overlaps and measurement errors. In this study, we applied emission fingerprinting technique provided by Zeiss LSM 510 META detector, and achieved concurrent detection of ten proteins expressed on the same endothelial cell sample. This approach can be further applied to real-time measurement of multiple proteins expressed on live single cell surface, and therefore will enable a novel approach of multiplexed live single cell detection.

Effects of basin topography and monsoon conditions on transport and occurrence of atmospheric PCDD/Fs in the Taichung Basin

Topographical and meteorological factors, such as monsoons, can drastically affect ambient dioxin levels. In order to better understand these phenomena, four sampling lines (comprising 16 sampling sites) were selected in accordance with the topographical characteristics and the transport paths of the Taichung Basin. The ambient air samples were simultaneously collected according to US EPA TO-9A. Seventeen polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were analyzed by a high-resolution gas chromatograph/high-resolution mass spectrometer. Field measurements indicated that, during monsoons, PCDD/Fs concentrations varied from 128 to 4,230 fg m(-3). Two locations, the pass between two tablelands and the valley in front of a mountain, had the highest PCDD/Fs concentrations; those concentrations were about two to five times greater than the average concentration. There were 189 analyses of 11 kinds of PCDD/Fs emission sources used to develop emission fingerprints for a CMB8.2 simulation. Chemical mass balance (CMB8.2) model simulation with PCDD/Fs and surface wind field measurements were performed. Results of CMB8.2 modeling indicated that the major source of most sites was secondary copper smelting. The CMB8.2 model indicated the effects of hills and river valleys on pollutant transport. Results indicated that secondary copper smelting must be controlled to reduce the ambient concentrations of PCDD/Fs in the Taichung Basin.

Differential Contribution of Dermal Resident and Bone Marrow–Derived Cells to Collagen Production during Wound Healing and Fibrogenesis in Mice

Recent studies show that bone marrow (BM)-derived cells migrating into a dermal wound promote healing by producing collagen type I. However, their contribution to the repair process has not been fully verified yet. It is also unclear whether BM-derived cells participate in dermal fibrogenesis. We have addressed these issues using transgenic mice that harbor tissue-specific enhancer/promoter sequences of α2(I) collagen gene linked to either enhanced green fluorescent protein (COL/EGFP) or the luciferase (COL/LUC) reporter gene. Following dermal excision or subcutaneous bleomycin administration, a large number of EGFP-positive collagen-producing cells appeared in the dermis of COL/EGFP reporter mice. When wild-type mice were transplanted with BM cells from transgenic COL/EGFP animals and subjected to dermal excision, no EGFP-positive BM-derived collagen-producing cells were detected throughout the repair process. Luciferase assays of dermal tissues from COL/LUC recipient mice also excluded collagen production by BM-derived cells during dermal excision healing. In contrast, a limited but significant number of CD45-positive collagen-producing cells migrated from BM following bleomycin injection. These results indicate that resident cells in the skin are the major source of de novo collagen deposition in both physiological and pathological conditions, whereas BM-derived cells participate, in part, in collagen production during dermal fibrogenesis.

A new method for the characterisation and quantitative speciation of base metal smelter stack particulates

Base metal smelters may be a source of particulates containing metals of environmental concern released to the atmosphere. Knowledge of the quantitative chemical speciation of particulate releases from base metal smelters will be of value in smelter emission fingerprinting, site-specific risk assessments, predictions of the behaviour of smelter stack particulates released to the environment and in resolving liability issues related to current and historic releases. Accordingly, we have developed an innovative approach comprising bulk chemical analysis, a leaching procedure, X-ray diffraction analysis and scanning electron microscopy/electron probe microanalysis characterisation in a step-wise apportioning procedure to derive the quantitative speciation of particulate samples from the stacks of three copper smelters designated as A, B and C. For the A smelter stack particulates, the major calculated percentages were 29 CuSO(4), 20 ZnSO(4).H(2)O, 13 (Cu(0.94)Zn(0.06))(2)(AsO(4))(OH), 11 PbSO(4) and four As(2)O(3). For the B smelter stack particulates, the primary calculated percentages were 20 ZnSO(4).H(2)O, 20 PbSO(4), 12 CuSO(4) and nine As(2)O(3). Finally, we calculated that the C smelter stack particulates mostly comprised 34 ZnSO(4).H(2)O, 19 (Cu(0.84)Zn(0.16))(AsO(3)OH), 11 PbSO(4), 10 As(2)O(3) and nine Zn(3)(AsO(4))(2). Between 56% and 67% by weight of the smelter stack particulates, including the As, was soluble in water. For these and other operations, the data and approach may be useful in estimating metals partitioning among water, soil and sediment, as well as predictions of the effects of the stack particulates released to the environment.

Hydrocarbon emission fingerprints from contemporary vehicle/engine technologies with conventional and new fuels

The present paper presents results from the analysis of 29 individual C 2–C 9 hydrocarbons (HCs) specified in the European Commission Ozone Directive. The 29 HCs are measured in exhaust from common, contemporary vehicle/engine/fuel technologies for which very little or no data is available in the literature. The obtained HC emission fingerprints are compared with fingerprints deriving from technologies that are being phased out in Europe. Based on the total of 138 emission tests, thirteen type-specific fingerprints are extracted (Mean ± SD percentage contributions from individual HCs to the total mass of the 29 HCs), essential for receptor modelling source apportionment. The different types represent exhaust from Euro3 and Euro4 light-duty (LD) diesel and petrol-vehicles, Euro3 heavy-duty (HD) diesel exhaust, and exhaust from 2-stroke preEuro, Euro1 and Euro2 mopeds. The fuels comprise liquefied petroleum gas, petrol/ethanol blends (0–85% ethanol), and mineral diesel in various blends (0–100%) with fatty acid methyl esters, rapeseed methyl esters palm oil methyl esters, soybean oil methyl or sunflower oil methyl esters. Type-specific tracer compounds (markers) are identified for the various vehicle/engine/fuel technologies. An important finding is an insignificant effect on the HC fingerprints of varying the test driving cycle, indicating that combining HC fingerprints from different emission studies for receptor modelling purposes would be a robust approach. The obtained results are discussed in the context of atmospheric ozone formation and health implications from emissions (mg km −1 for LD and mopeds and mg kW h −1 for HD, all normalised to fuel consumption: mg dm −3 fuel) of the harmful HCs, benzene and 1,3-butadiene. Another important finding is a strong linear correlation of the regulated “total” hydrocarbon emissions (tot-HC) with the ozone formation potential of the 29 HCs (ΣPO 3 = (1.66 ± 0.04) × tot-RH; r 2 = 0.93). Tot-HC is routinely monitored in emission control laboratories, whereas C 2–C 9 are not. The revealed strong correlations broadens the usability of data from vehicle emission control laboratories and facilitates the comparison of the ozone formation potential of HCs in exhaust from of old and new vehicle/engine/fuel technologies.