Ground-Level Ozone Mapping in Large Urban Areas Using Multivariate Statistical Analysis: Application to the São Paulo Metropolitan Area

Guardani, Roberto; Aguiar, J. L. Barroso de; Nascimento, Cláudio Augusto Oller do; Lacava, Carlos I.V.; Yanagi, Yoshio

doi:10.1080/10473289.2003.10466188

Cited by 27 publications

(25 citation statements)

References 20 publications

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“…Consistently, O3 concentrations tended to be somewhat higher (around 80 μg/m 3 in the early afternoon) at these relatively removed stations compared to stations right by roads, as O3 reacts away with NO. 70,71 Further, as one would expect, CO concentrations tended to be higher at stations located by busy intersections (e.g., Cerqueira César and Congonhas exceeding 1 ppm).…”

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confidence: 74%

Reduction in local ozone levels in urban São Paulo due to a shift from ethanol to gasoline use

Salvo

Geiger

2014

Nature Geosci

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It has been proposed that lower NOX emission fuels such as ethanol can mitigate air pollution from vehicles burning oil-based hydrocarbons. Yet, existing modeling and laboratory studies, even those seeking to simulate the same environment, vary in their predictions of how gasoline/ethanol blends affect atmospheric pollutant concentrations, including ozone. Importantly, ambient concentrations have not been evaluated during an actual -as opposed to hypothetical -shift in fuel mix in a real-world environment. Here, we report the first such study, for the subtropical megacity of São Paulo, Brazil. We combine detailed street-hour level data on regulated pollutant concentrations, meteorology, and traffic with fuel shares from a consumer demand model to compare concentrations across subsamples that differ only in the fuel mix but are otherwise similar in meteorology, anthropogenic activity, and biogenic emissions. As the gasoline share of the bi-fuel light-duty vehicle fleet rose by 62 percentage points, we estimate a robust and statistically significant reduction of about 20% in ozone concentrations, and less precise increases in NO and CO concentrations. We propose that our "model-free" analysis potentially accounts for the interaction between anthropogenic and biogenic emissions and caution that successful strategies against ozone pollution require knowledge of the PRE-PRINT DATE: 18 February, 2014 Ozone levels are relatively high in São Paulo, with hourly concentrations above 75 and 125 g/m 3 , respectively, 2.7 and 5.3 times more likely than for PM10 in our sample. Light transportation is a key contributor to air pollution in this gridlocked metropolis [1][2][3] , with large public health implications [4][5][6][7] . In 2011, 40% of the city's 6 million active light-duty vehicles -likely accounting for over one-half of all light vehicle distance traveled -possessed bi-fuel capability. This capability allowed consumers to choose between gasoline (an E25 or E20 blend) and ethanol E100 at the pump 8 , as both fuels were ubiquitous among São Paulo's retailers 9,10 . In recent years, governmentcontrolled gasoline prices held steady whereas market-set sugarcane ethanol prices tracked the significant swings in the world price of sugar 8,10 . This empirical setting provides a rarely observed opportunity to examine whether urban air pollution was impacted by emissions that transitioned between gasoline and ethanol -both combustion and evaporation. São Paulo city currently features clogged hypothetical large-scale switch from a fossil fuel over to a biofuel in a large urban center. Analysis of Concentrations, Traffic, and Meteorology at Street-Hour LevelOur study cross-examines a large amount of measured data, detailed at the streethour level (Fig. 2), from several sources: (i) concentrations of regulated "priority" . We combine the extensive pollutantmeteorology-traffic data with: (iv) weekly gasoline and ethanol prices at the pump, obtained from the National Agency for Oil, Biofuels and Natural Gas (ANP) 10 , which in tu...

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confidence: 74%

Reduction in local ozone levels in urban São Paulo due to a shift from ethanol to gasoline use

Salvo

Geiger

2014

Nature Geosci

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“…Several statistical methods have been used in order to study the behaviour of pollutants in general (see for instance Álvarez et al 2005;Austin and Tran 1999;Flaum et al 1996;Guardani et al 1999Guardani et al , 2003Horowitz 1980;Lanfredi and Macchiato 1997;Larsen et al 1990;Leadbetter 1991;Pan and Chen 2008;Piegorsch et al 1998;Roberts 1979a,b;Smith 1989;Zolghadri and Henry 2004). When the interest resides in modelling the number of times the ozone concentration surpasses a given threshold, a possibility is the use of Poisson models (see for example Achcar et al 2009aAchcar et al ,b, 2008Javits 1980;Loomis et al 1996;Raftery 1989).…”

Section: Introductionmentioning

confidence: 99%

Using stochastic volatility models to analyse weekly ozone averages in Mexico City

Achcar

Rodrigues²,

Tzintzun

2010

Environ Ecol Stat

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In this paper we make use of some stochastic volatility models to analyse the behaviour of a weekly ozone average measurements series. The models considered here have been used previously in problems related to financial time series. Two models are considered and their parameters are estimated using a Bayesian approach based on Markov chain Monte Carlo (MCMC) methods. Both models are applied to the data provided by the monitoring network of the Metropolitan Area of Mexico City. The selection of the best model for that specific data set is performed using the Deviance Information Criterion and the Conditional Predictive Ordinate method.

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“…Among them we may quote [21,39,40] and [43] applying extreme values theory; [20] using multivariate analysis; [19] considering neural networks; [5,7] and [27] applying Markov models; [15,26,30] and [35] considering time series analysis; [23] with an analysis of the behaviour the maximum measurements of ozone in Mexico City; and [50] using minmax statistical models. (In [37], we find a review of some of the statistical methodologies commonly used in the study of environmental problems.…”

Section: Introductionmentioning

confidence: 99%

Comparing the Number of Ozone Exceedances in Different Seasons of the Year in Mexico City

Achcar¹,

Sousa²,

Rodrigues

et al. 2010

Environ Model Assess

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Ozone air pollution is a serious problem in several cities of the world. Hence, to analyse the behaviour of this pollutant is a very important issue. One problem of interest is to study the behaviour of the inter-occurrences times between two ozone exceedances, i.e. between two days in which the pollutant's measurement surpasses a given threshold. Another interest resides in comparing the behaviour of ozone measurements in different seasons of the year. In this paper we use some Poisson models to analyse this problem. The time interval at which the ozone measurements were taken is split into subintervals corresponding roughly to the seasons of the year. We consider three parametric forms for the mean of the Poisson model, and consequently for the mean of the inter-occurrences times. In each model, the parameters describing its mean are estimated using Bayesian inference via Markov chain Monte Carlo methods. The models are applied to the ozone measurements provided by the Mexico City monitoring network. Theoretical results suggest that an increase has occurred in the mean inter-exceedances times and this is corroborated by the observed data. Differences between the behaviour of the pollutant during different seasons of the year are also detected as well as similarities in the same season in different years. Besides estimating the mean of the Poisson models, inference for the possible presence and location of change-points indicating change of parameters of the model is also performed.

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Ground-Level Ozone Mapping in Large Urban Areas Using Multivariate Statistical Analysis: Application to the São Paulo Metropolitan Area

Abstract: A statistical study on the behavior of ground-level O 3

Cited by 27 publications

References 20 publications

Reduction in local ozone levels in urban São Paulo due to a shift from ethanol to gasoline use

Reduction in local ozone levels in urban São Paulo due to a shift from ethanol to gasoline use

Using stochastic volatility models to analyse weekly ozone averages in Mexico City

Comparing the Number of Ozone Exceedances in Different Seasons of the Year in Mexico City

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