ABSTRACT: The objective of this study was to determine the size and composition of atmospheric aerosols in the downtown area of the city of São Paulo, Brazil, for a polluted and an unpolluted period. Aerosols were sampled with a portable air sampler (PAS), Micro-Orifice Uniform Deposit Impactor (MOUDI), and Scanning Mobility Particle Sizer. At the study site, air quality is poor, especially during the winter, high concentrations of pollutants being emitted primarily by the light- and heavy-duty vehicle fleet. We analyzed mass, black carbon (BC), Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Br, Rb, Sn, Zr, and Pb. During the polluted period, diurnal PM(10) was higher than nocturnal PM(10), whereas the inverse was true during the unpolluted period. The FPM was rich in BC, S, and Pb, whereas CPM was rich in Al, Si, Ca, Ti, and Fe. Mass balance was performed by category: ammonium sulfate, sodium chloride, crustal material, BC, and other. The PAS-determined FPM was mainly BC. The MOUDI-determined FPM crustal material explained more mass than did ammonium sulfate and BC during the polluted period, whereas ammonium sulfate had the largest mass during the unpolluted period. Crustal material was the major CPM component, followed by ammonium sulfate and BC. During the unpolluted period, FPM concentrations were lower, whereas those of ammonium sulfate were relatively higher, especially at night, and particle number was inversely proportional to particle size. Aerosol growth was more intense during the polluted period.
Environmental Monitoring and Assessment 04/2011; 184(2):969-84. · 1.40 Impact Factor
ABSTRACT: Ozone dynamics depend on meteorological characteristics such as wind, radiation, sunshine, air temperature and precipitation. The aim of this study was to determine ozone trajectories along the northern coast of Portugal during the summer months of 2005, when there was a spate of forest fires in the region, evaluating their impact on respiratory and cardiovascular health in the greater metropolitan area of Porto. We investigated the following diseases, as coded in the ninth revision of the International Classification of Diseases: hypertensive disease (codes 401-405); ischemic heart disease (codes 410-414); other cardiac diseases, including heart failure (codes 426-428); chronic obstructive pulmonary disease and allied conditions, including bronchitis and asthma (codes 490-496); and pneumoconiosis and other lung diseases due to external agents (codes 500-507). We evaluated ozone data from air quality monitoring stations in the study area, together with data collected through HYbrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model analysis of air mass circulation and synoptic-scale zonal wind from National Centers for Environmental Prediction data. High ozone levels in rural areas were attributed to the dispersion of pollutants induced by local circulation, as well as by mesoscale and synoptic scale processes. The fires of 2005 increased the levels of pollutants resulting from the direct emission of gases and particles into the atmosphere, especially when there were incoming frontal systems. For the meteorological case studies analyzed, peaks in ozone concentration were positively associated with higher rates of hospital admissions for cardiovascular diseases, although there were no significant associations between ozone peaks and admissions for respiratory diseases.
International Journal of Bioclimatology Biometeorology 03/2011; 55(2):187-202. · 2.25 Impact Factor
ABSTRACT: Emission of fine particles by mobile sources has been a matter of great concern due to its potential risk both to human health and the environment. Although there is no evidence that one sole component may be responsible for the adverse health outcomes, it is postulated that the metal particle content is one of the most important factors, mainly in relation to oxidative stress. Data concerning the amount and type of metal particles emitted by automotive vehicles using Brazilian fuels are limited. The aim of this study was to identify inhalable particles (PM(10)) and their trace metal content in two light-duty vehicles where one was fueled with ethanol while the other was fueled with gasoline mixed with 22% of anhydrous ethanol (gasohol); these engines were tested on a chassis dynamometer. The elementary composition of the samples was evaluated by the particle-induced x-ray emission technique. The experiment showed that total emission factors ranged from 2.5 to 11.8 mg/km in the gasohol vehicle, and from 1.2 to 3 mg/km in the ethanol vehicle. The majority of particles emitted were in the fine fraction (PM(2.5)), in which Al, Si, Ca, and Fe corresponded to 80% of the total weight. PM(10) emissions from the ethanol vehicle were about threefold lower than those of gasohol. The elevated amount of fine particulate matter is an aggravating factor, considering that these particles, and consequently associated metals, readily penetrate deeply into the respiratory tract, producing damage to lungs and other tissues.
Journal of Toxicology and Environmental Health Part A 01/2010; 73(13-14):901-9. · 1.83 Impact Factor
ABSTRACT: 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 São 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
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
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 > 2 × 104ppm−1 min−1; olefins with a kOH < 7 × 104ppm−1 min−1; olefins with a kOH > 7 × 104ppm−1 min−1; ethene; and formaldehyde, which are the principal species related to the production, transport, storage and combustion of
Water Air and Soil Pollution 10/2008; 195(1):201-213. · 1.63 Impact Factor
ABSTRACT: The main sources of reactive hydrocarbons (RHC) and nitrogen oxides (NOx), ozone precursors, in the Metropolitan Area of São Paulo (MASP) in the southeast of Brazil are emissions from vehicles fleets.
Ambient surface ozone and particulate matter concentrations are air quality problem in the MASP. This study examined the impact
that implementing a control program for mobile emissions has on ozone concentrations, An episode of high surface ozone concentrations
occurring in the MASP during the March 13–15, 2000 period was used as a case study that was modeled for photochemical oxidants
using the California Institute of Technology/Carnegie Mellon University three-dimensional photochemical model. Different scenarios
were analyzed in relationship to the implementation of the Programa Nacional de Controle de Poluição por Veículos Automotores (PROCONVE, National Program to Control Motor Vehicle Pollution). Scenario 1 assumed that all vehicles were operating within
PROCONVE guidelines. Scenarios 2 and 3 considered hypothetical situations in which the PROCONVE was not implemented. Scenario
2 set the premise that vehicles were using pre-1989 technology, whereas scenario 3 allowed for technological advances. A base
case scenario, in which the official emission inventory for the year 2000 was employed, was also analyzed. The CIT model results
show agreement with most measurements collected during 13–15 March 2000 modeling episode. Mean normalized bias for ozone,
CO, RHC and NO
are approximately 9.0, 6.0, −8.3, 13.0%, respectively. Tropospheric ozone concentrations predicted for scenario 2 were higher
than those predicted for scenarios 1, 3 and base case. This study makes a significant contribution to the evaluation of air
quality improvement and provides data for use in evaluating the economic costs of implementing a program of motor vehicle
pollution control aimed at protecting human health.
Environmental Fluid Mechanics 03/2007; 7(2):95-119. · 1.67 Impact Factor
ABSTRACT: Ozone concentrations in the heavily polluted metropolitan area of São Paulo (MASP), in Brazil, frequently exceed established international standards. This study aims to describe the impact that three meteorological variables (mixing height, wind speed and air temperature) on the ozone concentration, as well as reactive hydrocarbon (RHC) limitation and nitrogen oxide (NOx) limitation, have on ozone formation in the area. To achieve these objectives the California Institute of Technology (CIT) Eulerian air quality model was applied combined with the same methodology described in Baertsch-Ritter et al. [2004. Atmospheric Chemistry and Physics 4, 423–438] In addition, NOx and RHC emission inventory reductions were used to evaluate their sensitivities in the CIT model. A simulation of an episode occurring in the MASP on 22 August 2000, when a peak ozone level of 127 ppbv was recorded, is presented. In the CIT model results for the base case, primary pollutant concentrations and ozone concentrations are in good agreement with the measured data. In addition, changes in mixing height, wind speed and air temperature input files have the greatest effect on peak ozone in the MASP, and the isolated effect of RHC emission inventory reduction leads to 26% lower ozone levels than in the base case. Based on the results of this study, we can conclude that with reduction of RHC emission could provide the best scenario for promoting lower ozone concentrations in the MASP.