Potential health impact of ultrafine particles under clean and polluted urban atmospheric conditions: a model-based study

The main goal of this study was to improve the knowledge of ultrafine particle number distributions in large urban areas and also to call the attention to the importance of these particles on assessing health risks. Measurements of aerosol size distributions were performed during 2 weeks, with distinct pollutant concentrations (polluted and clean periods), on the rooftop of a building located in downtown of the megacity of São Paulo, Brazil. CO, NO2, PM10, SO2, and O3 concentrations and meteorological variables were also used. Aerosol size distribution measurements showed that geometric mean diameters of the size spectra in the polluted period are on average considerably larger than those in the clean one. Besides the fact that total number of ultrafine particles did not show significant differences, during the polluted period, geometric mean diameter was larger than during the clean one. The results of a mathematical model of particle deposition on human respiratory tract indicated a more significant effect of smaller particles fraction of the spectra, which predominate under clean atmospheric conditions. The results also indicated that urban environmental conditions usually considered good for air quality, under the criteria of low mass concentration, do not properly serve as air quality standard to very small particles. In the size range of ultrafine particles, this traditional clean atmospheric condition can offer a strong risk to pulmonary hazards, since the cleansing of the atmosphere creates good conditions to increase the concentration of nucleation mode particles

Variabilidade das Concentrações do o3 Troposférico: Dados de Superfície e Sondagens Medidos durante a Campanha Primavera de o3. Em 2006

Variabilidade das concentrações do O3 troposférico: dadosde superfície e sondagens medidos durante a campanha“Primavera de O3” em 200

Intermediate-scale horizontal isoprene concentrations in the near-canopy forest atmosphere and implications for emission heterogeneity

The emissions, deposition, and chemistry of volatile organic compounds (VOCs) are thought to be influenced by underlying landscape heterogeneity at intermediate horizontal scales of several hundred meters across different forest subtypes within a tropical forest. Quantitative observations and scientific understanding at these scales, however, remain lacking, in large part due to a historical absence of canopy access and suitable observational approaches. Herein, horizontal heterogeneity in VOC concentrations in the nearcanopy atmosphere was examined by sampling from an unmanned aerial vehicle (UAV) flown horizontally several hundred meters over the plateau and slope forests in central Amazonia during the morning and early afternoon periods of the wet season of 2018. Unlike terpene concentrations, the isoprene concentrations in the near-canopy atmosphere over the plateau forest were 60% greater than those over the slope forest. A gradient transport model constrained by the data suggests that isoprene emissions differed by 220 to 330%from these forest subtypes, which is in contrast to a 0% difference implemented in most present-day biosphere emissions models (i.e., homogeneous emissions). Quantifying VOC concentrations, emissions, and other processes at intermediate horizontal scales is essential for understanding the ecological and Earth system roles of VOCs and representing them in climate and air quality models. © 2019 National Academy of Sciences. All rights reserved

Tropospheric ozone formation sensitivity to vehicle emission in the Metropolitan Area of São Paulo

Este trabalho teve como objetivo avaliar a sensibilidade da formação do ozônio troposférico às emissões veiculares de compostos orgânicos voláteis (COVs) e NOx na Região Metropolitana de São Paulo (RMSP). Essa avaliação foi realizada através de modelagem numérica com modelo de qualidade do ar fotoquímico tridimensional. Para a determinação da especiação dos COVs veiculares foram realizadas duas campanhas intensivas de medidas em túneis da cidade de São Paulo, constituindo portanto em um esforço na melhoria do inventário de emissões da RMSP. Das medidas de concentração dos COVs, CO, NOx e SO2 foram calculados fatores de emissão e com base na relação entre as concentrações dos COVs emitidos pela exaustão veicular, juntamente com informações obtidas previamente da composição do combustível líquido e das emissões evaporativas foi construído um inventário dos COVs emitidos pela gasolina, álcool e diesel na RMSP, utilizado nas simulações de qualidade do ar. Foram realizadas simulações de referência utilizando o modelo fotoquímico densenvolvido no Caltech Institute of Technology (CIT) e Carnegie Mellon University, e as concentrações obtidas das simulações foram comparadas às concentrações observadas pela rede de monitoramento da Companhia de Tecnologia de Saneamento Ambiental (CETESB) para três períodos distintos, em termos dos níveis de poluição e condições meteorológicas: 22-24 de agosto de 2000; 13-15 de março de 2000 e 06-10 de setembro de 2004. Com base nas simulações de referência foram calculados os potenciais de formação de ozônio para 24 espécies através do cálculo de métricas de reatividade e também realizada a análise da sensibilidade da formação do ozônio às emissões de COVs, NOx, CO e de cada COV individualmente para os três períodos. Da avaliação da análise de sensibilidade do ozônio às emissões pôde-se verificar que o ozônio foi altamente sensível às emissões dos COVs nos três períodos estudados e portanto, o controle da emissão dos COVs é o mais efetivo para o controle do ozônio na RMSP. Dentre os COVs analisados as espécies representadas por ARO2 (aromáticos 2), OLE1 (olefinas 1), OLE2 (olefinas 2), ETHE (eteno) e HCHO (formaldeído) foram as cinco às quais o ozônio (medido em termos de seu potencial de formação e emissão) apresentou maior sensibilidade constituindo-se nas mais relevantes. Adicionalmente, foram avaliados os impactos de diferentes cenários de uso de gasolinas reformuladas nas concentrações de ozônio em todo o domínio em relação ao cenário atual de referência. A máxima resposta do ozônio às reduções de emissão foi obtida após 3 dias do início do controle. Os cenários 1 (redução de 11,1% das frações de olefinas, aromáticos e benzeno da gasolina) e 2 (redução de 20,0% das frações de olefinas, aromáticos e benzeno da gasolina) que refletem as propostas de reformulação da gasolina para 2007 e 2009 resultaram em reduções das concentrações de ozônio, mas insuficientes para a redução para abaixo do padrão de qualidade do ar de ozônio.The main goal of this work was the study of the ozone sensitivity to volatile organic compounds (VOCs) and NOx emitted by vehicles in the Metropolitan Area of São Paulo (MASP), using as tool the numerical modeling. Two intensive campaigns in-tunnel of São Paulo city were performed as an effort to improve the MASP emission inventory. From concentrations measurements of VOCs, CO, NOx and SO2 they were calculated emission factors and based on the relation among the VOCs emitted by exhaust, and also together with informations from liquid fuel and evaporative composition was built the VOCs composition from gasoline, alcohol and diesel emission in the MASP. Together with the totals emitted officially, it was obtained the inventory of emissions used in the simulation. Base case simulations were performed using the photochemical model developed at Caltech Institute of Technology (CIT) and Carnegie Mellon University, and the concentrations simulated were compared with observations from the air quality network of the São Paulo State Companhia de Tecnologia de Saneamento Ambiental (CETESB). Three periods were studied: August 22-24 of 2000; March 13-15 of 2000 and September 06-10 of 2004. Ozone potential formation was calculated for 24 species using reactivity metrics, and was also performed the ozone sensitivity analysis to emission of VOCs, NOx, CO and each VOC individually, for all the periods. From ozone sensitivity analysis to emissions, it was found that the ozone is higher sensitivity to VOCs emissions than to NOx. Therefore, the VOCs reduction is more effective on ozone control in the MASP. Among the VOCs analyzed the species represented by ARO2 (aromatics 2), OLE1 (olefins 1), OLE2 (olefins 2), ETHE (ethene) and HCHO (formaldehyde) were identified as the most important concerning ozone formation in the MASP. Additionally, the impacts of different scenarios of reformulated gasoline in the ozone concentrations in whole domain and time were evaluated in relation to current scenario (base case). The higher reductions of ozone associated to emission control was identified to occur after 3 days of the beginning of control. The scenarios 1 (reduction of 11.1% of the olefins, aromatics and benzene fractions from gasoline) and 2 (reduction of 20.0% of the olefins, aromatics and benzene fractions from gasoline) that reflect the proposals for reformulated gasoline in 2007 and 2009 resulted in reductions of the ozone concentrations, but insufficient for the reduction below of the ozone air quality standard

Ozone Formation Potential in the Megacity of São Paulo

In Brazil, since 1989 there was implemented the PROCONVE (Control Program for the air pollution by motor vehicles) that established limits to emissions from new vehicles. A decrease in pollutants levels was observed associated to the emissions control, mainly for CO. However Ozone and Inhalable Particulate Matter levels routinely exceed the 160 mg m-3 hourly and 150 mg m-3 daily of Brazilian National Ambient Air-Quality Standard, respectively. São Paulo is a megacity with about 10.6 millions of inhabitants. The footprint of a megacity encompasses not only the area physically occupied, but also the area that contributes resources and, in turn, is affected by wastes and pollutants. The main sources of pollutants in São Paulo are associated to the production, transportation and burning of vehicular fuel. São Paulo has a complex topography, localized 50 km away from the Atlantic Ocean. In some events during the winter, low relative humidity of air, low wind speed and sunny days promoted by high-pressure systems, which hinder the entrance of cold fronts in São Paulo, provide conditions for occurrence of ozone episodes and consequently bad air quality. The control of ozone is not only important for Sao Paulo but also for other neighbor cities that are impacted by the photochemical precursors and ozone from the megacity. Simulations of meteorology and chemistry for two different periods (summer and winter) were performed for the Metropolitan Area of São Paulo (MASP) with different emission scenarios. A 3D eulerian photochemical model was employed to estimate the impact of organic compounds on ozone. The chemical mechanism used was SAPRC99, which is the recommended chemical mechanism for reactivity assessment. The use of 3D models allows examining the effect of different meteorological or environmental factors on 3D reactivities. Base case simulations were conducted from August 22, 2000 to August 24, 2000 and from March 13, 2000 to March 15, 2000 for MASP. The levels of pollutants were represented by the model with values of correlation coefficient for ozone of 0.93 and 0.92 and average normalized bias of -23.9 and -34.4 respectively for both periods. Simulations to evaluate the individual ozone potential formation of VOCs were performed considering variations of 15% in the emissions, which produce stable and close-to-linear responses. These perturbations were performed equally for all the VOCs and the ozone incremental reactivity was analyzed. The maximum increase of ozone in relation to the base case were achieved for ARO2 (aromatics 2 - aromatics with kOH > 2x104 ppm-1 min-1), OLE1 (olephines 1 - alkenes (other than ethene) with kOH 7x104 ppm-1 min-1), HCHO (formaldehyde), ARO1 (aromatics 1 - aromatics with kOH < 2x104 ppm-1 min-1), C2H2 (acetylene), ALK2 (alkanes 2 - alkanes and other non-aromatic compounds that react only with OH, and have kOH between 5 x 103 and 1 x 104 ppm-1 min-1) and CCHO (acetaldehyde), indicating the large importance of these species on ozone formation in São Paulo. The importance of this study is connected to the particular characteristics of São Paulo atmosphere regarding meteorological features and ozone precursors.Pages: 139-14

Ozone formation potentials of volatile organic compounds and ozone sensitivity to their emission in the megacity of Sao Paulo, Brazil

In the present study, a three-dimensional Eulerian photochemical model was employed to estimate the impact that organic compounds have on tropospheric ozone formation in the Metropolitan Area of Sao Paulo (MASP). In the year 2000, base case simulations were conducted in two periods: August 22-24 and March 13-15. Based on the pollutant concentrations calculated by the model, the correlation coefficient relative to observations for ozone ranged from 0.91 to 0.93 in both periods. In the simulations employed to evaluate the ozone potential of individual VOCs, as well as the sensitivity of ozone to the VOC/NO(x) emission ratio, the variation in anthropogenic emissions was estimated at 15% (according to tests performed previously variations of 15% were stable). Although there were significant differences between the two periods, ozone concentrations were found to be much more sensitive to VOCs than to NO(x) in both periods and throughout the study domain. In addition, considering their individual rates of emission from vehicles, the species/classes that were most important for ozone formation were as follows: aromatics with a kOH>2x 10(4) ppm(-1) min(-1); olefins with a kOH 7 x 10(4) ppm(-1) min(-1); olefins with a kOH 7 x 10(4) ppm(-1) min(-1); ethene; and formaldehyde, which are the principal species related to the production, transport, storage and combustion of fossil fuels.FAPESP Fundacao de Amparo a Pesquisa do Estado de Sao Paulo[02/09060-1

Dynamical Downscaling of Future Climate Change Scenarios in Urban Heat Island and Its Neighborhood in a Brazilian Subtropical Area

According to IPCC reports, a greater frequency, intensity and duration of heat waves in urban areas are expected. This is related to the dynamical evolution of the cities, due the changes of the natural surface modifies the roughness pattern reduce the wind intensity, modify the available humidity in the soil and the radiative properties. These topics characterize the formation of the urban heat island (UHI). A dynamical downscaling of A2 and B1 future scenarios was made for Londrina, a medium-size city of Southern Brazil, using Weather Research Forecasting model, to investigate the impact of this projections on the UHI formation and intensity, as well for rural area, which consistent an important agricultural landscape. For this, an evaluation of the model and the scenarios were done to investigate the current trends. The results shows a tendency of following the worst proposed scenarios (A2), and a drier rural area for the sustainable projection, which has directly influence on the urban heat island intensity and formation, and in the agriculture of the region

Effects of Environmental and Socioeconomic Inequalities on Health Outcomes: A Multi-Region Time-Series Study

The gradual increase in temperatures and changes in relative humidity, added to the aging and socioeconomic conditions of the population, may represent problems for public health, given that future projections predict even more noticeable changes in the climate and the age pyramid, which require analyses at an appropriate spatial scale. To our knowledge, an analysis of the synergic effects of several climatic and socioeconomic conditions on hospital admissions and deaths by cardiorespiratory and mental disorders has not yet been performed in Brazil. Statistical analyses were performed using public time series (1996&ndash;2015) of daily health and meteorological data from 16 metropolitan regions (in a subtropical climate zone in South America). Health data were stratified into six groups according to gender and age ranges (40&ndash;59; 60&ndash;79; and &ge;80 years old) for each region. For the regression analysis, two distributions (Poisson and binomial negative) were tested with and without zero adjustments for the complete series and percentiles. Finally, the relative risks were calculated, and the effects based on exposure&ndash;response curves were evaluated and compared among regions. The negative binomial distribution fit the data best. High temperatures and low relative humidity were the most relevant risk factors for hospitalizations for cardiovascular diseases (lag = 0), while minimum temperatures were important for respiratory diseases (lag = 2 or 3 days). Temperature extremes, both high and low, were the most important risk factors for mental illnesses at lag 0. Groups with people over 60 years old presented higher risks for cardiovascular and respiratory diseases, while this was observed for the adult group (40-59 years old) in relation to mental disorders. In general, no major differences were found in the results between men and women. However, regions with higher urbanization levels presented risks, mainly for respiratory diseases, while the same was observed for cardiovascular diseases for regions with lower levels of urbanization. The Municipal Human Development Index is an important factor for the occurrence of diseases and deaths for all regions, depending on the evaluated group, representing high risks for health outcomes (the value for hospitalization for cardiovascular diseases was 1.6713 for the female adult group in the metropolitan region Palmas, and the value for hospitalization for respiratory diseases was 1.7274 for the female adult group in the metropolitan region Campo Mour&atilde;o). In general, less developed regions have less access to adequate health care and better living conditions

Meteorological Effects of Green Infrastructure on a Developing Medium Latin American City: A Numerical Modeling Assessment

Urban areas concentrate more than 50% of the world’s population and are highly impacted by human activities, mainly due to high population density, directly affecting the micro-climate. In this sense, green infrastructures (GIs) have been pointed out to be helpful in mitigating these effects in large urban areas, where most of the studies were conducted. Therefore, this study evaluates the impacts on meteorological variables in a medium-sized city through the Weather Research and Forecasting model by implementing urban classes of Local Climate Zones (LCZ). Five urban parks and an urban lake were identified and expanded in the inner model grid to analyze the effects of GIs on meteorological variables in the urban environment. Results show that the 10 m wind speed can present an improvement for all statistical indices due to the better vertical representation of urban structures in the central urban area by the LCZ urban classes. In addition, green areas contributed locally to reducing the urban heat island (UHI) effects, resulting in cooling rates around these infrastructures. Compared to the lake, the use of the urban LCZ classes has proven to be an effective way to improve the representation of meteorological variables by a mesoscale weather model. Regarding GIs, this practice performs environmental services capable of mitigating the effects of UHI, sustaining the importance of these systems in urban projects, even for medium-sized cities. Finally, these findings provide support for public decision-makers in creating Master Plans for medium-sized cities regarding the implementation of GIs

Numerical Study of Meteorological Factors for Tropospheric Nocturnal Ozone Increase in the Metropolitan Area of São Paulo

One of the central problems in large cities is air pollution, mainly caused by vehicular emissions. Tropospheric ozone is an atmospheric oxidizing gas that forms in minimal amounts naturally, affecting peoples’ health. This pollutant is formed by the NO2 photolysis, creating a main peak during the day. Nighttime secondary peaks occur in several parts of the world, but their intensity and frequency depend on the local condition. In this sense, this works aims to study the local characteristics for tropospheric nocturnal ozone levels in the Metropolitan Area of São Paulo, in Brazil, using the Simple Photochemical Module coupled to the Brazilian Developments on the Regional Atmospheric Modeling System. For this, three different situations of nocturnal occurrence were studied. The results show that the nocturnal maximum of ozone concentrations is related to the vertical transport of this pollutant from higher levels of the atmosphere to the surface and is not related to the synoptic condition