Transportation fleet emissions have a dominant role in air quality because of their significant contribution to ozone precursor and greenhouse gas emissions. Regulatory policies have emphasized improvements in vehicle fuel economy, alternative fuel use, and engine and vehicle technologies as approaches for obtaining transportation systems that support sustainable development. This study examined the air quality impacts of the partial electrification of the transportation fleet and the use of biofuels for the Austin Metropolitan Statistical Area under a 2030 vision of regional population growth and urban development using the Comprehensive Air Quality Model with extensions (CAMx). Different strategies were considered including the use of Plug-in Hybrid Electric Vehicles (PHEVs) with nighttime charging using excess capacity from electricity generation units and the replacement of conventional petroleum fuels with different percentages of the biofuels E85 and B100 along or in combination. Comparisons between a 2030 regional vision of growth assuming a continuation of current development trends (denoted as Envision Central Texas A or ECT A) in the Austin MSA and the electrification and biofuels scenarios were evaluated using different metrics, including changes in daily maximum 1-hour and 8-hour ozone concentrations, total area, time integrated area and total daily population exposure exceeding different 1-hour ozone concentration thresholds. Changes in ozone precursor emissions and predicted carbon monoxide and aldehyde concentrations were also determined for each scenario. Maximum changes in hourly ozone concentration from the use of PHEVs ranged from -8.5 to 2.2 ppb relative to ECT A. Replacement of petroleum based fuels with E85 had a lesser effect than PHEVs on maximum daily ozone concentrations. The maximum reduction due to replacement of 100% of gasoline fuel in light and heavy duty gasoline vehicles by E85 ranged from -2.1 to 2.8 ppb. The magnitude of the effect was sensitive to the biofuel penetration level. Unlike E85, B100 negatively impacted hourly ozone concentrations relative to the 2030 ECT A case. As the replacement level of petroleum-diesel fuel with B100 in diesel vehicles increased, hourly ozone concentrations increased as well. However, changes due to the penetration of B100 were relatively smaller than those due to E85 since the gasoline fraction of the fleet is larger than the diesel fraction. Because of the reductions in NOx emissions associated with E85, the results for the biofuels combination scenario were similar to those for the E85 scenario. Also, the results showed that as the threshold ozone concentration increased, so too did the percentage reductions in total daily population exposure for the PHEV, E85, and biofuel combination scenarios relative to ECT A. The greatest reductions in population exposure under higher threshold ozone concentrations were achieved with the E85 100% and 17% PHEV with EGU controls scenarios, while the B100 scenarios resulted in greater population exposure under higher threshold ozone concentrations. / text

<p>Slamsvällning orsakar stora problem i avloppsreningsverk med biologisk rening i aktivt slamprocesser. Slamsvällning orsakas av filamentösa (trådformiga) bakterier, som inverkar negativt på slammets sedimenteringsegenskaper.</p><p>Himmerfjärdens vattenreningsverk har drabbats av detta problem som leder till ett stabilt lager av slam på ytan av sedimenteringsbassängen som inte sedimenterar.</p><p>För att lösa detta problem behandlades returslammet från sedimenteringsbassängen med ozon för att minska mängden filamentösa bakterier i returslamflödet. Ozon är en starkt oxiderande gas, som är väl användbar för icke-specifik bekämpning av slamsvällning. När ozon kommer i kontakt med den filamentösa bakteriens cellvägg penetreras det in i cellen, varvid cellen lyserar.</p><p>Ozonbehandlingen resulterade i en förminskning av antalet filamentösa bakterier. Ozonbehandling av returslam förbättrade sedimenteringsegenskaperna hos svällande slam utan att påverka andra viktiga mikrobiologiska processer t.ex. nitrifikation.</p> / <p>Bulking sludge causes major problems in wastewater treatment plants that deal with biological nutrient removal in activated sludge processes. Bulking sludge is caused by filamentous bacteria, which have a negative impact on the sludge settling properties.</p><p>Himmerfjärden wastewater treatment plant suffers from this type of problem with bulking sludge which creates a stable layer at the surface that does not settle in the clarifier.</p><p>In order to solve this problem, on site generated ozone was used to decrease the amount of filamentous bacteria in the return activated sludge flow. Ozone is a strong oxidant is suitable for non-specific bulking control. It stresses the filamentous bacteria causing inactivation through cell wall disintegration.</p><p>The ozone treatment resulted in decreased abundance of filamentous bacteria. Ozone treatment of the recycled activated sludge improves the settling properties of bulking sludge, without interfering with other important microbiological processes e.g. nitrification.</p>

Stratosphere Troposphere exchange (STE) is important to study as it controls the chemical composition of the upper troposphere/lower stratosphere (UTLS) and thus the radiative balance of this region. STE also controls the transport of chemicals into the stratosphere which are vital to ozone depletion. The troposphere and the stratosphere have specific chemical characteristics and the transition region between these regions displays characteristics of both. Ozone and water vapour concentrations can be used as tracers for the characteristics of the troposphere and stratosphere. This thesis develops measures in tracer space, which allow the determination of the strength and depth of atmospheric mixing between the troposphere and the stratosphere in extratropical regions. The application of entropy as a measure of atmospheric mixing as introduced by Patmore and Toumi [2006], is improved in this study. This is a measure of how the ozone and water vapour mixing ratios vary as a result of mixing. An additional metric to give further information on the form of the mixing line in tracer space is also developed. This measure uses the ozone and water vapour mixing ratios at the boundaries of the transition region (BO3 and BH2O). This study uses data from ozonesondes and hygrometers, along with satellite data from the Atmospheric Infrared Sounder (AIRS). The ozone product from AIRS is also validated as part of this study. The entropy, BO3 and BH2O measures from this study, are successfully shown to detect regions of enhanced mixing in comparison studies. A key comparison shows that the measures developed in this study are able to produce comparable conclusions to higher resolution aircraft data, with regards to mixing. The separation of entropy, BO3 and BH2O, into different categories allows mixing processes to be assigned to some of the categories. Mixing is shown to have geographic preference, with some regions having significantly more mixing. Some categories have preference with regards to their location either poleward or equatorward of the jet stream. In addition, some information as to the direction of the vertical transport, whether stratosphere to troposphere or vice versa, is obtained.

The utilization of radial growth responses of trees to diagnose air pollution injury, and problems of growth defects interfering with the establishment of growth chronologies, is discussed. Cores from trees in an air pollution-stressed forest are examined for their potential to crossdate. Less than half, and usually less than a third of the trees on all plots can be crossdated, and number appears to be associated with changing conditions along a transect of elevational and pollution levels. Chronologies developed along this transect are presented.

Les oxydes d'azote atmosphériques (NOx=NO+NO2) sont des composés clefs en chimie de l'environnement, jouant un rôle central pour la capacité oxydante de l'atmosphère et le cycle de l'azote. La composition isotopique du nitrate atmosphérique (NO?3 particulaire et HNO3 gazeux), constituant leur puits ultime, renseigne sur leur bilan chimique. Le rapport 15N/14N donne une indication de leurs sources, alors que l'anomalie isotopique en oxygène (?17O=d17O-0.52×d18O) révèle la nature de leurs mécanismes d'oxydation. Des études couplées de d15N et ?17O d'échantillons de nitrate atmosphérique collectés dans l'Arctique, en Antarctique et dans l'atmosphère marine au dessus de l'Océan Atlantique, où le bilan des NOx est souvent mal connu ont été effectuées. À ces fins, le défi que constitue la mesure simultanée des trois rapports isotopiques du nitrate (17O/16O, 18O/16O et 15N/14N) dans le même échantillon représentant moins d'une micromole a été relevé. La solution adoptée tire avantage des propriétés d'une bactérie dénitrifiante, utilisée pour convertir le nitrate en N2O, dont la composition isotopique totale a été mesurée en utilisant un système automatisé de chromatographie en phase gazeuse et spectrométrie de masse de rapport isotopique. Les principaux résultats obtenus via les isotopes de l'oxygène permettent l'identification claire de transitions saisonnières entre voies d'oxydation des NOx, y compris le rôle majeur des composés halogénés réactifs au printemps polaire en régions côtières. Les isotopes de l'azote ont quant à eux permis d'apporter de nouvelles contraintes sur le cycle de l'azote dans les régions polaires, grâce au fractionnement significatif induit par les phénomènes de remobilisation post-dépôt affectant le nitrate dans le manteau neigeux, et l'émission de NOx qui en découle

Biodiesel use and production has significantly increased in the United States and in other parts of the world in the past decade. This change is driven by energy security and global climate legislation mandating reductions in the use of petroleum-based diesel. Recent air quality research has shown that emission of some pollutants such as CO, particulate matter (PM), SO2, hydrocarbons, and carcinogenic polycyclic aromatic hydrocarbons (PAHs) is greatly reduced with biodiesel. However, studies have also shown that some unregulated emissions, such as gas-phase carbonyls, are increased with biodiesel combustion. Very limited research has been done to investigate the particle-phase carbonyl and quinone emissions from biodiesel combustion. Also, very limited studies have investigated the ozone oxidation of biodiesel exhaust PM. Fatty acid methyl esters (FAMEs) are found in high abundance in biodiesel exhaust PM. The presence of these FAMEs in biodiesel exhaust PM can potentially alter the kinetics of the reactions between ozone and particle-phase PAHs. In this study, an Armfield CM-12 automotive light-duty diesel engine operated on a transient drive cycle was used to generate PM from various waste vegetable oil (WVO) and soybean biodiesel blends (containing 0%, (B00), 10% (B10), 20% (B20), 50% (B50), and 100% (B100) biodiesel by volume). The primary PM emissions were sampled using Teflon-coated fiberfilm filters. Laboratory PAHs, FAMEs, and B20 exhaust PM were exposed to ~0.4 ppm ozone for time periods ranging from 0-24 hours in order to study the effect of FAMEs and biodiesel exhaust PM on the ozonolysis of PAHs. Organic chemical analysis of samples was performed using gas chromatography/mass spectrometry (GC/MS). PAHs, carbonyls, FAMEs, and n-alkanes were quantified in the exhaust PM of petrodiesel, WVO and soybean fuel blends. The emission rates of the total PAHs in B10, B20, B50, and B100 exhaust PM decreased by 0.006-0.071 ng/µg (5-51%) compared to B00, while the emission rates for the FAMEs increased with increasing biodiesel content in the fuel. The emission rates of the total n-alkanes in B10, B20, B50, and B100 exhaust PM decreased by 0.5-21.3 ng/µg (4-86%) compared to B00 exhaust PM. The total emission rates of the aliphatic aldehydes in biodiesel exhaust PM (B10, B20, B50, and B100) increased by 0.019-2.485 ng/µg (36-4800%) compared to petrodiesel. The emission rates of the total aromatic aldehydes, total aromatic ketones, and total quinones all generally decreased with increasing biodiesel content in the fuel. With the exception of benzo[a]pyrene, the pseudo-first order ozone reaction rate constants of all the PAHs decreased by 1.2-8 times in the presence of the FAMEs. Phenanthrene, fluoranthene, and pyrene were the only PAHs detected in the B20 exhaust PM, and their ozone reaction rate constants were about 4 times lower than those obtained when the PAHs alone were exposed to ozone. The findings of this study indicate that there are both positive and negative effects to emissions associated with biodiesel use in light-duty diesel engines operating on transient drive cycle.

O desenvolvimento de novos materiais que possam ser aplicados como sensores resistivos de gás torna-se mais importante a cada dia devido sua importância no monitoramento ambiental, controle de emissão industrial e aplicações médicas. Desta forma, esforços têm sido realizados a fim de desenvolver dispositivos funcionais que apresentem uma alta sensibilidade, seletividade e baixo consumo de energia operando em temperaturas próximas a temperatura ambiente. O composto ZnO nanoestruturado puro e/ou dopado exibindo diferentes morfologias têm sido apontado como um candidato promissor na detecção de diferentes tipos de gases devido suas propriedades eletrônicas e da alta razão superfície/volume que facilitam a adsorção de espécies gasosas sobre sua superfície. Adicionalmente, diferentes estudos tem mostrado que o desempenho de sensores resistivos pode ser melhorado através da inserção de dopantes na rede ou na superfície do material sensor. Motivados por essas considerações, neste trabalho, filmes finos e espessos de composição ZnO e Zn1-xCoxO nanoestruturados obtidos através dos métodos dos precursores poliméricos, RF sputtering e tratamento hidrotermal foram avaliados visando sua aplicação como sensor dos gases O3, NO2 e CO. O estudo das propriedades estruturais de longo alcance investigadas através da técnica de difração de raios X mostrou que a adição de cobalto causa uma diminuição da intensidade dos picos de difração. Medidas do espectro de absorção de raios-X indicaram que nas amostras obtidas pelo método dos precursores poliméricos e RF sputtering, respectivamente, os átomos de Co assumem predominantemente o estado de valência 2+ e 3 +. A composição química da superfície das amostras foi analisada através da técnica de espectroscopia de fotoelétrons de raios X (XPS) enquanto as propriedades microestruturais foram avaliadas por microscopia eletrônica de varredura (MEV) e microscopia de força atômica (AFM). Medidas da resistência elétrica das amostras foram utilizadas para avaliar as propriedades sensoras das amostras, como a sensibilidade, a seletividade, o tempo de resposta e de recuperação quando expostos a diferentes concentrações dos gases O3, CO e NO2. As medidas de resistência elétrica quando os filmes foram expostos as estes gases mostrou que as três metodologias de síntese foram eficientes na obtenção de amostras que apresentam um grande potencial para serem aplicadas como sensores de gás. Entretanto, a amostra obtida por RF-sputtering apresentou as melhores propriedades de detecção ao gás ozônio com, valor de resposta quarenta (40) vezes maior, que foi atribuído a sua alta rugosidade e as características microestruturais apresentadas por essa amostra. As amostras Zn1-xCoxO obtidas pelo método dos precursores poliméricos exibiram uma maior sensibilidade ao ozônio e uma menor temperatura de trabalho em relação a amostra ZnO, preparada por esse mesmo método. Além disso, a adição de cobalto contribuiu para a seletividade do composto. A melhora das propriedades sensoras foram atribuídas a uma melhor atividade catalítica causada pelos íons Co e a presença de defeitos na superfie do material, que favoreceu a adsorção das moléculas de oxigênio na superfície da amostra / The development of new materials to be applied as gas resistive sensors has become increasingly important regarding environmental monitoring, industrial emission control and medical applications. Pure or doped ZnO nanostructured compounds that exhibit different morphologies have been identified as promising candidates for the detection of different types of toxic gases due to their electronic properties and high surface/volume ratio, which facilitates the adsorption of gaseous species on their surface. Studies have shown the performance of resistive sensors can be improved by the doping or presence of defects in the network or at the surface of the sensor material. The present doctoral thesis addresses the evaluation of ZnO and Zn1-xCoxO nanostructured films obtained by the polymeric precursor method, RF sputtering deposition and hydrothermal treatment and their application as O3, NO2 and CO gas sensors. Their long-range order structure investigated by the X-ray diffraction technique showed the addition of cobalt decreases the intensity of diffraction peaks. Measurements of X-ray absorption spectra at Co K-edge indicated Co atoms in the samples obtained by the RF sputtering technique and polymeric precursor method predominantly assume the 2+ and 3+ oxidation state. Measurements of electrical resistance were used in the evaluation of ZnO and Zn1-xCoxO nanostructured films sensing properties such as sensitivity, selectivity, response and recovery times under different concentrations of O3, CO and NO2 gases. The electrical resistance of the films exposed to those gases showed the three methodologies of synthesis effectively obtained samples to be applied as gas sensors. However, the sample obtained by the RF-sputtering deposition technique exhibited the best detection properties towards ozone gas and a forty-time higher response value, attributed to greater roughness and microstructural features. Zn1-xCoxO samples obtained by the polymeric precursor method exhibited higher sensitivity and a lower working temperature in relation to ozone gas. Such characteristics were attributed to a better catalytic activity promoted by the addition of Co ions and the presence of defects on the surface of the material, which favors the adsorption of oxygen molecules on the sample surface.

Introdução: A poluição atmosférica é um problema de saúde pública em todo o mundo. Os efeitos adversos produzidos pelos poluentes do ar estão fortemente associados com as doenças respiratórias e cardiovasculares e, com magnitude inferior, aos desfechos da gestação. Objetivo: estimar a relação entre os poluentes PM10 e O3 e o baixo peso ao nascer em crianças nascidas na cidade de Santo André. Casuística e métodos: este é um estudo de coorte histórica. Foram incluídos todos os bebês nascidos de mães que vivem no município de Santo André - São Paulo Brasil, entre 2000 e 2006 com declarações de nascimento de vivos concluído. A Companhia de Tecnologia de Saneamento Ambiental Cetesb forneceu dados diários do material particulado (PM10), ozônio (O3), temperatura e umidade. Foram realizadas análises descritivas e de regressão logística. Resultados: Dos 58.114 nascimentos ocorridos entre 2000 e 2006, 5,91 % dos bebês apresentaram baixo peso ao nascer. Houve uma relação dosedependente entre as concentrações de PM10 e o baixo peso ao nascer. Concentrações de PM10 no quarto quartil no terceiro trimestre aumentaram o risco de baixo peso ao nascer em 32% (Razão de Chance: 1,32; IC95%: 1,15 1,50) quando comparado com os valores do primeiro quartil. Comportamentos semelhantes foram observados nos demais trimestres. Não foram observados riscos para o O3. Conclusão: o aumento na concentração de PM10, na cidade de Santo André, no período estudado, produziu um aumento na chance de ocorrência de baixo peso ao nascer Este efeito foi observado mesmo não ocorrendo ultrapassagem dos padrões de qualidade do ar / Introduction: The atmospheric pollution is a public health problem worldwide. The adverse effects related to air pollutants are robustly associated with respiratory and cardiovascular diseases and, in a lesser extent, with pregnancy adverse outcomes. Objective: estimating the relationship between air pollutants PM10 and O3 and low birth weight of children were borne in the city of Santo André, São Paulo. Casuistic and methods: This is a crossectional study. We included in the study all newborns of mothers that were inhabitants of Santo André, São Paulo, Brazil, and that were born from 2000 to 2006. The São Paulo State Environmental Agency (CETESB) provided daily records of particulate matter (PM10), temperature, and humidity. We performed descriptive analysis and logistic regressions. Results: Among the 58,114 newborns it was observed a low birth weight rate of 5.9%. There was a dose-response relationship between PM10 concentrations and low birth weight. Particles concentrations in the highest quartile in the third trimester of pregnancy increased the risk of low birth weight in 32% ((Odds Ratio: 1,32; 95% CI: 1,15 1,50) when compared with the first quartile. The same pattern of effect was observed in the other trimesters. For the O3 not were detected risks. Conclusion: The increase in PM10 concentrations, in Santo André, during the studied period, lead to an increase in the odds of low birth weight. This effect was observed even though there was no surpassing of air quality standards

Os materiais de estrutura perovskita compreendem um vasto grupo de compostos cuja estrutura na sua forma mais simples pode ser representada pela f&oacute;rmula qu&iacute;mica ABO3. Uma das principais vantagens que a estrutura perovskita apresenta &eacute; o alto grau de flexibilidade em acomodar uma grande variedade de &aacute;tomos nos s&iacute;tios A e B, permitindo um maior controle de suas propriedades f&iacute;sicas e qu&iacute;micas bem como a manuten&ccedil;&atilde;o de sua estrutura b&aacute;sica, mesmo para altas concentra&ccedil;&otilde;es de &aacute;tomos substituintes. Devido estas propriedades, estes materiais t&ecirc;m sido aplicados com sucesso como capacitores, varistores, fotoeletrodos, mem&oacute;riasferroel&eacute;tricas e sensores de gases. Nas &uacute;ltimas d&eacute;cadas, tem sido reportada a utiliza&ccedil;&atilde;o do titanato de estr&ocirc;ncio (SrTiO3, ST) na forma de filmes finos e espessos como sensor de g&aacute;s oxig&ecirc;nio em altas temperaturas (&gt;500 &deg;C). Recentemente, foi mostrado que o titanato de estr&ocirc;ncio dopado com Fe apresentava uma excelente sensibilidade ao g&aacute;s oz&ocirc;nio. Entretanto, neste trabalho, somente uma composi&ccedil;&atilde;o foi caracterizada e nem todas as propriedades importantes em rela&ccedil;&atilde;o a esta aplica&ccedil;&atilde;o foram completamente exploradas. Neste contexto, esta tese de doutorado teve como objetivo verificar o efeito da substitui&ccedil;&atilde;o do &aacute;tomo de estr&ocirc;ncio pelo lant&acirc;nio e do tit&acirc;nio pelo Ferro no composto SrTiO3 na forma de p&oacute; e filmes finos nanoestruturados com a finalidade de verificar o efeito destas substitui&ccedil;&otilde;es nas propriedades sensoras do material. Inicialmente, com o objetivo de avaliar a influ&ecirc;ncia da adi&ccedil;&atilde;o de La na estrutura do composto ST, amostras na forma de p&oacute; do sistema Sr1-xLaxTiO3.(SLT) foram preparadas atrav&eacute;s do m&eacute;todo dos precursores polim&eacute;ricos. Posteriormente, pelo mesmo m&eacute;todo, foram sintetizadas amostras do sistema SrTi1-xFexO3 (STF) e Sr1-XLaxTi1-yFeyO3 (SLTF). A partir das amostras na forma de p&oacute; e na forma de solu&ccedil;&atilde;o, filmes finos e espessos foram respectivamente obtidos atrav&eacute;s das t&eacute;cnicas de deposi&ccedil;&atilde;o por feixe de el&eacute;trons (EBD) e spin-coating (SC). As amostras nanoestruturadas na forma de p&oacute; e na forma de filmes foram caracterizadas por difra&ccedil;&atilde;o de raios X, espectroscopia de absor&ccedil;&atilde;o de raios X (XANES) na borda K do Ti e do Fe e espectroscopia de fotoel&eacute;trons excitados por raios X (XPS). A an&aacute;lise morfol&oacute;gica foi realizada atrav&eacute;s das t&eacute;cnicas de microscopia eletr&ocirc;nica de varredura (MEV) e microscopia de for&ccedil;a at&ocirc;mica (MFA). As amostras do sistema STF e SLTF na forma de filmes finos foram avaliadas em rela&ccedil;&atilde;o &agrave; sensibilidade aos gases O3, NO2, NH3 e CO. Os resultados indicaram que os filmes do sistema SLTF depositados pela t&eacute;cnica de deposi&ccedil;&atilde;o por feixe de el&eacute;trons apresentam uma maior sensibilidade ao g&aacute;s oz&ocirc;nio, enquanto o filme de mesma composi&ccedil;&atilde;o depositado pelo m&eacute;todo de spin-coating apresentou uma melhor estabilidade e tempo de recupera&ccedil;&atilde;o em rela&ccedil;&atilde;o a este mesmo g&aacute;s. / The perovskite structure materials comprise a large group of compounds with the structure in simple form can be represented by the ABO3. chemical formula. The main advantage that the perovskite structure presents is the high degree of flexibility to accommodate a wide variety of atoms in sites A and B, allowing a greater control of physical and chemical properties of the material, maintaining its structure even for a high concentrations of substituent\'s. Due to these properties, these materials have been successfully applied as capacitors, varistors, photoelectrodes, ferroelectric memories and gas sensors. In the last decade, strontium titanate (SrTiO3, ST) in the form of thin and thick films have been reported as oxygen gas sensor at higher temperatures (&gt; 500 &deg;C). Recently, strontium titanate doped with Fe was used as the first ozone sensor. However, the work was carried out only with a certain composition and some important properties for this application have not been fully exploited. In this context, this PhD thesis aimed to the synthesis of strontium titanate system in powder form and nanostructured thin films with the substitution of Sr for La and Ti for Fe. In order to verify the effect of these substitutions in material properties initially Sr1-xLaxTiO3 (SLT) samples were prepared in powder form by the polymeric precursor method in order to evaluate the influence of the addition of La in the structure of the compound ST. Subsequently, samples were synthesized from SrTi1-x Fex O3 (STF) and Sr1-XLaxTi1-yFeyO3 (SLTF) systems through the polymeric precursors, which were used for the deposition of thin and thick films, which were respectively obtained through electron beam deposition techniques (EBD) and spin-coating (SC). Samples in the form of nanostructured powder and thin films were characterized by X-ray diffraction, X-ray absorption spectroscopy (XANES) at Ti and Fe K-edges and by X-ray photoelectron spectroscopy (XPS). Morphological analysis was performed using the scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques. The STF and SLTF samples in a thin film form were evaluated towards their sensitivity to O3, NO2, NH3 and CO gases. The results indicated that SLTF films deposited by electron beam deposition technique exhibit higher sensitivity to ozone gas. However the same composition deposited by spin-coating showed a better stability and recovery time relative to the same gas.

A qualidade do ar dos grandes centros urbanos é impactada diretamente pela emissão de poluentes dos veículos automotores. São dois os principais indicadores da deterioração da qualidade do ar: a concentração de material particulado e de ozônio. A concentração desses poluentes frequentemente atinge valores preocupantes, em especial na Região Metropolitana de São Paulo. O ozônio é um poluente secundário formado a partir de reações fotoquímicas em ambiente com a presença de compostos orgânicos voláteis e óxidos de nitrogênio, dentre os principais compostos precursores emitidos pela combustão dos motores dos veículos. A metodologia desenvolvida busca caracterizar o impacto da circulação dos veículos utilizando um índice, baseado na especiação, quantificação e reatividade dos precursores de ozônio emitidos. Esse índice pode identificar o impacto de um modelo de veículo e atender a demanda por rotulagem ambiental ou o impacto de um conjunto de veículos e subsidiar políticas públicas de redução das emissões / Air quality in large urban centers is directly impacted by the emission of pollutants from motor vehicles. There are two main indicators of the deterioration of air quality: the concentration of particulate matter and ozone. The concentration of these pollutants often reaches alarming values, particularly in São Paulo Metropolitan Area. Ozone is a secondary pollutant formed by photochemical reactions in atmosphere with the presence of volatile organic compounds and nitrogen oxides, precursors compounds emitted by combustion in vehicle engines. The methodology developed seeks to characterize the impact of the movement of vehicles using an index based on speciation, quantification and reactivity of emitted ozone precursors. This index can identify the impact of a vehicle and meet the demand for environmental labeling or the impact of a set of vehicles and support public policies to reduce emissions