Genotoxicity and composition of particulate matter from biomass burning in the eastern Brazilian Amazon region

In the present study Tradescantia pallida micronucleus (Trad-MCN) bioassay was used to assess the genotoxicity of particulate matter with a mass median aerodynamic diameter less than 10 pm (PM(10)) in Tangara da Serra (MT), a Brazilian Amazon region that suffers the impact of biomass burning. The levels of PM (coarse and fine size fractions) and black carbon (BC) collected were also measured. Furthermore, the alkanes and polycyclic aromatic hydrocarbons (PAHs) were identified and quantified in the samples taken during the burning period by gas chromatography with flame ionization detection (GC-FID). The PM and BC results for both fractions indicate a strong correlation (p < 0.001). The analysis of alkanes indicates an anthropic influence. Retene was the most abundant PAH found, an indicator of biomass burning, and 12 other PAHs considered to be potentially mutagenic and/or carcinogenic were identified in this sample. The Trad-MCN bioassay showed a significant increase in micronucleus frequency during the period of most intense burning, possibly related to the mutagenic PAHs that were found in such extracts. This study demonstrated that Trad-MCN was sensitive and efficient in evaluating the genotoxicity of organic compounds from biomass burning. It further emphasizes the importance of performing chemical analysis, because changes in chemical composition generally have a negative effect on many living organisms. This bioassay (ex situ), using T. pallida with chemical analysis, is thus recommended for characterizing the genotoxicity of air pollution. Crown Copyright (C) 2011 Published by Elsevier Inc. All rights reserved.

Characterization of the optical properties of atmospheric aerosols in Amazonia from long-term AERONET monitoring (1993-1995 and 1999-2006)

We present a new climatology of atmospheric aerosols (primarily pyrogenic and biogenic) for the Brazilian tropics on the basis of a high-quality data set of spectral aerosol optical depth and directional sky radiance measurements from Aerosol Robotic Network (AERONET) Cimel Sun-sky radiometers at more than 15 sites distributed across the Amazon basin and adjacent Cerrado region. This network is the only long-term project (with a record including observations from more than 11 years at some locations) ever to have provided ground-based remotely-sensed column aerosol properties for this critical region. Distinctive features of the Amazonian area aerosol are presented by partitioning the region into three aerosol regimes: southern Amazonian forest, Cerrado, and northern Amazonian forest. The monitoring sites generally include measurements from the interval 1999-2006, but some sites have measurement records that date back to the initial days of the AERONET program in 1993. Seasonal time series of aerosol optical depth (AOD), angstrom ngstrom exponent, and columnar-averaged microphysical properties of the aerosol derived from sky radiance inversion techniques (single-scattering albedo, volume size distribution, fine mode fraction of AOD, etc.) are described and contrasted for the defined regions. During the wet season, occurrences of mineral dust penetrating deep into the interior were observed.

Determination of anthropogenic and biogenic compounds on atmospheric aerosol collected in urban, biomass burning and forest areas in Sao Paulo, Brazil

This study was conducted at three sites of different characteristics in Sao Paulo State Sao Paulo (SPA), Piracicaba (PRB) and Mate Atlantica Forest (MAT) PM(10), n-alkanes. pristane and phytane, PAHs, water-soluble ions and biomass burning tracers like levoglucosan and retene, were determined in quartz fiber filters. Samplings occurred on May 8th to August 8th, 2007 at the MAT site; on August 15th to 29th in 2007 and November 10th to 29th in 2008 at the PRB site and, March 13th to April 4th in 2007 and August 7th to 29th in 2008 at the SPA site Aliphatic compounds emitted biogenically were less abundant at the urban sites than at the forest site, and its distribution showed the influence of tropical vascular plants Air mass transport front biomass burning regions is likely to impact the sites with specific molecular markers The concentrations of all species were variable and dependent of seasonal changes In the most dry and polluted seasons, n-alkane and canon total concentrations were similar between the megacity and the biomass burning site PAHs and inorganic ion abundances were higher at Sao Paulo than Piracicaba, yet, the site influenced by biomass burning seems lobe the most impacted by the organic anion abundance in the atmosphere Pristane and phytane confirm the contamination by petroleum residues at urban sites, at the MAT site, biological activity and long range transport of pollutants might influence the levels of pristane (C) 2010 Elsevier B V All rights reserved

Short terms effects of air pollution from biomass burning in mucociliary clearance of Brazilian sugarcane cutters

Nasal mucociliary system is the first line of defense of the upper airways and may be affected acutely by exposure to particulate matter (PM) from biomass burning. Several epidemiologic studies have demonstrated a consistent association between levels of air pollution from biomass burning with increases in hospitalization for respiratory diseases and mortality. To determine the acute effects of exposure to particulate matter from biomass burning in nasal mucociliary transport by saccharin transit time (STT) test, we studied thirty-three non-smokers and twelve light smokers sugarcane cutters in two periods: pre-harvest season and 4 h after harvest at the first day after biomass burning. Lung function, exhaled carbon monoxide (CO), nasal symptoms questionnaire and mucociliary clearance (MC) were assessed. Exhaled CO was increased in smokers compared to non-smokers but did not change significantly after harvest. In contrast, SIT was similar between smokers and non-smokers and decreased significantly after harvest in both groups (p < 0.001). Exposure to PM from biomass burning did not influence nasal symptoms. Our results suggest that acute exposure to particulate matter from sugarcane burned affects mucociliary clearance in smokers and non-smokers workers in the absence of symptoms. (C) 2011 Elsevier Ltd. All rights reserved.

Short terms effects of air pollution from biomass burning in mucociliary clearance of Brazilian sugarcane cutters

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Laboratory evaluation of Amazon forest biomass burning emissions

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Biomass burning fuel consumption rates: a field measurement database

Landscape fires show large variability in the amount of biomass or fuel consumed per unit area burned. Fuel consumption (FC) depends on the biomass available to burn and the fraction of the biomass that is actually combusted, and can be combined with estimates of area burned to assess emissions. While burned area can be detected from space and estimates are becoming more reliable due to improved algorithms and sensors, FC is usually modeled or taken selectively from the literature. We compiled the peerreviewed literature on FC for various biomes and fuel categories to understand FC and its variability better, and to provide a database that can be used to constrain biogeochemical models with fire modules. We compiled in total 77 studies covering 11 biomes including savanna (15 studies, average FC of 4.6 t DM (dry matter) ha 1 with a standard deviation of 2.2), tropical forest (n = 19, FC = 126 +/- 77), temperate forest (n = 12, FC = 58 +/- 72), boreal forest (n = 16, FC = 35 +/- 24), pasture (n = 4, FC = 28 +/- 9.3), shifting cultivation (n = 2, FC = 23, with a range of 4.0-43), crop residue (n = 4, FC = 6.5 +/- 9.0), chaparral (n = 3, FC = 27 +/- 19), tropical peatland (n = 4, FC = 314 +/- 196), boreal peatland (n = 2, FC = 42 [42-43]), and tundra (n = 1, FC = 40). Within biomes the regional variability in the number of measurements was sometimes large, with e. g. only three measurement locations in boreal Russia and 35 sites in North America. Substantial regional differences in FC were found within the defined biomes: for example, FC of temperate pine forests in the USA was 37% lower than Australian forests dominated by eucalypt trees. Besides showing the differences between biomes, FC estimates were also grouped into different fuel classes. Our results highlight the large variability in FC, not only between biomes but also within biomes and fuel classes. This implies that substantial uncertainties are associated with using biome-averaged values to represent FC for whole biomes. Comparing the compiled FC values with co-located Global Fire Emissions Database version 3 (GFED3) FC indicates that modeling studies that aim to represent variability in FC also within biomes, still require improvements as they have difficulty in representing the dynamics governing FC.

Micronucleus frequency in children exposed to biomass burning in the Brazilian Legal Amazon region: a control case study

Background: The Amazon represents an area of 61% of Brazilian territory and is undergoing major changes resulting from disorderly economic development, especially the advance of agribusiness. Composition of the atmosphere is controlled by several natural and anthropogenic processes, and emission from biomass burning is one with the major impact on human health. The aim of this study was to evaluate genotoxic potential of air pollutants generated by biomass burning through micronucleus assay in exfoliated buccal cells of schoolchildren in the Brazilian Amazon region. Methods: The study was conducted during the dry seasons in two regions of the Brazilian Amazon. The assay was carried out on buccal epithelial cells of 574 schoolchildren between 6-16 years old. Results: The results show a significant difference between micronucleus frequencies in children exposed to biomass burning compared to those in a control area. Conclusions: The present study demonstrated that in situ biomonitoring using a sensitive and low cost assay (buccal micronucleus assay) may be an important tool for monitoring air quality in remote regions. It is difficult to attribute the increase in micronuclei frequency observed in our study to any specific toxic element integrated in the particulate matters. However, the contribution of the present study lies in the evidence that increased exposure to fine particulate matter generates an increased micronuclei frequency in oral epithelial cells of schoolchildren.

Admissions due to pneumonia and biomass burning: a spatial approach

Objective: To identify spatial patterns in rates of admission for pneumonia among children and relate them to the number of fires reported in the state of Mato Grosso, Brazil. Methods: We conducted an ecological and exploratory study of data from the state of Mato Grosso for 2008 and 2009 on hospital admissions of children aged 0 to 4 years due to pneumonia and on fires in the same period. Admission rates were calculated and choropleth maps were plotted for rates and for fire outbreaks, Moran's I was calculated and the kernel estimator used to identify "hotspots." Data were analyzed using TerraView 3.3.1. Results: Fifteen thousand six hundred eighty-nine children were hospitalized (range zero to 2,315), and there were 161,785 fires (range 7 to 6,454). The average rate of admissions per 1,000 inhabitants was 2.89 (standard deviation [SD] = 5.18) and the number of fires per 1,000 inhabitants was 152.81 (SD = 199.91). Moran's I for the overall number of admissions was I = 0.02 (p = 0.26), the index for rate of admission was I = 0.02 (p = 0.21) and the index for the number of fires was I = 0.31 (p < 0.01). It proved possible to identify four municipalities with elevated rates of admissions for pneumonia. It was also possible to identify two regions with high admission densities. A clustering of fires was evident along what is known as the "arc of deforestation." Conclusions: This study identified municipalities in the state of Mato Grosso that require interventions to reduce rates of admission due to pneumonia and the number fires.

Recent shift from forest to savanna burning in the Amazon Basin observed by satellite

The numbers of fires detected on forest, savanna and transition lands during the 2002-10 biomass burning seasons in Amazonia are shown using fire count data and co-located land cover classifications from the Moderate Resolution Imaging Spectroradiometer (MODIS). The ratio of forest fires to savanna fires has varied substantially over the study period, with a maximum ratio of 0.65:1 in 2005 and a minimum ratio of 0.27:1 in 2009, with the four lowest years occurring in 2007-10. The burning during the droughts of 2007 and 2010 is attributed to a higher number of savanna fires relative to the drought of 2005. A decrease in the regional mean single scattering albedo of biomass burning aerosols, consistent with the shift from forest to savanna burning, is also shown. During the severe drought of 2010, forest fire detections were lower in many areas compared with 2005, even though the drought was more severe in 2010. This result suggests that improved fire management practices, including stricter burning regulations as well as lower deforestation burning, may have reduced forest fires in 2010 relative to 2005 in some areas of the Amazon Basin.

Emissions of volatile organic compounds from tropical savanna vegetation and biomass burning

This dissertation focuses on characterizing the emissions of volatile organic compounds (VOCs) from grasses and young trees, and the burning of biomass mainly from Africa and Indonesia. The measurements were performed with a proton-transfer-reaction mass spectrometer (PTR-MS). The biogenic emissions of tropical savanna vegetation were studied in Calabozo (Venezuela). Two field campaigns were carried out, the first during the wet season (1999) and the second during the dry season (2000). Three grass species were studied: T. plumosus, H. rufa and A. canescens, and the tree species B. crassifolia, C. americana and C. vitifolium. The emission rates were determined with a dynamic plant enclosure system. In general, the emissions increased exponentially with increasing temperature and solar radiation. Therefore, the emission rates showed high variability. Consequently, the data were normalized to a standard temperature of 30°C, and standard emission rates thus determined allowed for interspecific and seasonal comparisons. The range of average daytime (10:00-16:00) emission rates of total VOCs measured from green (mature and young) grasses was between 510-960 ngC/g/h. Methanol was the primary emission (140-360 ngC/g/h), followed by acetaldehyde, butene and butanol and acetone with emission rates between 70-200 ngC/g/h. The emissions of propene and methyl ethyl ketone (MEK) were <80 ngC/g/h, and those of isoprene and C5-alcohols were between 10-130 ngC/g/h. The oxygenated species represented 70-75% of the total. The emission of VOCs was found to vary by up to a factor of three between plants of the same species, and by up to a factor of two between the different species. The annual source of methanol from savanna grasses worldwide estimated in this work was 3 to 4.4 TgC, which could represent up to 12% of the current estimated global emission from terrestrial vegetation. Two of the studied tree species, were isoprene emitters, and isoprene was also their primary emission (which accounted for 70-94% of the total carbon emitted) followed by methanol and butene + butanol. The daytime average emission rate of isoprene measured in the wet season was 27 mgC/g/h for B. crassifolia, and 123 mgC/g/h for C. vitifolium. The daytime emissions of methanol and butene + butanol were between 0.3 and 2 mgC/g/h. The total sum of VOCs emission measured during the day in the wet season was between 30 and 130 mgC/g/h. In the dry season, in contrast, the methanol emissions from C. vitifolium saplings –whose leaves were still developing– were an order of magnitude higher than in the wet season (15 mgC/g/h). The isoprene emission from B. crassifolia in the dry season was comparable to the emission in the wet season, whereas isoprene emission from C. vitifolium was about a factor of three lower (~43 mgC/g/h). Biogenic emission inventories show that isoprenoids are the most prominent and best-studied compounds. The standard emission rates of isoprene and monoterpenes of the measured savanna trees were in the lower end of the range found in the literature. The emission of other biogenic VOCs has been sparsely investigated, but in general, the standard emissions from trees studied here were within the range observed in previous investigations. The biomass burning study comprised the measurement of VOCs and other trace-gas emissions of 44 fires from 15 different fuel types, primarily from Africa and Indonesia, in a combustion laboratory. The average sum of emissions (excluding CO2, CO and NO) from African fuels was ~18 g(VOC)/kg. Six of the ten most important emissions were oxygenated VOCs. Acetic acid was the major emission, followed by methanol and formaldehyde. The emission of methane was of the same order as the methanol emission (~5 g/kg), and that of nitrogen-containing compounds was ~1 g/kg. An estimate of the VOC source from biomass burning of savannas and grasslands worldwide suggests that the sum of emissions is about 56 Tg/yr, of which 34 Tg correspond to oxygenated VOCs, 14 Tg to unsaturated and aromatic compounds, 5 Tg to methane and 3 Tg to N-compounds. The estimated emissions of CO, CO2 and NO are 216, 5117 and 9.4 Tg/yr, respectively. The emission factors reported here for Indonesian fuels are the first results of laboratory fires using Indonesian fuels. Acetic acid was the highest organic emission, followed by acetol, a compound not previously reported in smoke, methane, mass 97 (tentatively identified as furfural, dimethylfuran and ethylfuran), and methanol. The sum of total emissions of Indonesian fuels was 91 g/kg, which is 5 times higher than the emissions from African fuels. The results of this study reinforces the importance of oxygenated compounds. Due to the vast area covered by tropical savannas worldwide, the biogenic and biomass burning emission of methanol and other oxygenated compounds may be important for the regional and even global tropospheric chemistry.

Laboratory study on the optical properties of absorbing atmospheric aerosols and field applications

The interaction between aerosols and sun light plays an important role in the radiative balance of Earth’s atmosphere. This interaction is obtained by measuring the removal (extinction), redistribution (scattering), and transformation into heat (absorption) of light by the aerosols; i.e. their optical properties. Knowledge of these properties is crucial for our understanding of the atmospheric system. rn Light absorption by aerosols is a major contributor to the direct and indirect effects on our climate system, and an accurate and sensitive measurement method is crucial to further our understanding. A homebuilt photoacoustic sensor (PAS), measuring at a 532nm wavelength, was fully characterized and its functionality validated for measurements of absorbing aerosols. The optical absorption cross-sections of absorbing polystyrene latex spheres, to be used as a standard for aerosol absorption measurements, were measured and compared to literature values. Additionally, a calibration method using absorbing aerosol of known complex refractive index was presented.rn A new approach to retrieve the effective broadband refractive indices (mbroad,eff) of aerosol particles by a white light aerosol spectrometer (WELAS) optical particle counter (OPC) was achieved. Using a tandem differential mobility analyzer (DMA)-OPC system, the nbroad,eff are obtained for both laboratory and field applications. This method was tested in the laboratory using substances with a wide range of optical properties and it was used in ambient measurements to retrieve the nbroad,eff of biomass burning aerosols in a nationwide burning event in Israel. The retrieved effective broadband refractive indices for laboratory generated scattering aerosols were: ammonium sulfate (AS), glutaric acid (GA), and sodium chloride, all within 4% of literature values. For absorbing substances, nigrosine and various mixtures of nigrosine with AS and GA were measured, as well as a lightly absorbing substance, Suwannee river fulvic acid (SRFA). For the ambient measurements, the calibration curves generated from this method were to follow the optical evolution of biomass burning (BB) aerosols. A decrease in the overall aerosol absorption and scattering for aged aerosols during the day after the fires compared to the smoldering phase of the fires was found. rn The connection between light extinction of aerosols, their chemical composition and hygroscopicity for particles with different degrees of absorption was studied. The extinction cross-section (σext) at 532nm for different mobility diameters was measured at 80% and 90% relative humidity (RH), and at an RH<10%. The ratio of the humidified aerosols to the dry ones, fRHext(%RH,Dry), is presented. For purely scattering aerosols, fRHext(%RH,Dry) is inversely proportional with size; this dependence was suppressed for lightly absorbing ones. In addition, the validity of the mixing rules for water soluble absorbing aerosols is explored. The difference between the derived and calculated real parts of the complex RIs were less than 5.3% for all substances, wavelengths, and RHs. The obtained imaginary parts for the retrieved and calculated RIs were in good agreement with each other, and well within the measurement errors of retrieval from pulsed CRD spectroscopy measurements. Finally, a core-shell structure model is also used to explore the differences between the models, for substances with low growth factors, under these hydration conditions. It was found that at 80% RH and for size parameters less than 2.5, there is less than a 5 % difference between the extinction efficiencies calculated with both models. This difference is within measurement errors; hence, there is no significant difference between the models in this case. However, for greater size parameters the difference can be up to 10%. For 90% RH the differences below a size parameter of 2.5 were up to 7%.rn Finally, the fully characterized PAS together with a cavity ring down spectrometer (CRD), were used to study the optical properties of soot and secondary organic aerosol (SOA) during the SOOT-11 project in the AIDA chamber in Karlsruhe, Germany. The fresh fractal-like soot particles were allowed to coagulate for 28 hours before stepwise coating them with SOA. The single scattering albedo for fresh fractal-like soot was measured to be 0.2 (±0.03), and after allowing the soot to coagulate for 28 hours and coating it with SOA, it increased to 0.71(±0.01). An absorption enhancement of the coated soot of up to 1.71 (±0.03) times from the non-coated coagulated soot was directly measured with the PAS. Monodisperse measurements of SOA and soot coated with SOA were performed to derive the complex refractive index (m) of both aerosols. A complex refractive index of m = 1.471(±0.008) + i0.0(±0.002) for the SOA-αO3 was retrieved. For the compact coagulated soot a preliminary complex refractive index of m = 2.04(+0.21/-0.14) + i0.34(+0.18/-0.06) with 10nm(+4/-6) coating thickness was retrieved.rn These detail properties can be use by modelers to decrease uncertainties in assessing climatic impacts of the different species and to improve weather forecasting.rn

Predictability of biomass burning in response to climate changes

Climate is an important control on biomass burning, but the sensitivity of fire to changes in temperature and moisture balance has not been quantified. We analyze sedimentary charcoal records to show that the changes in fire regime over the past 21,000 yrs are predictable from changes in regional climates. Analyses of paleo- fire data show that fire increases monotonically with changes in temperature and peaks at intermediate moisture levels, and that temperature is quantitatively the most important driver of changes in biomass burning over the past 21,000 yrs. Given that a similar relationship between climate drivers and fire emerges from analyses of the interannual variability in biomass burning shown by remote-sensing observations of month-by-month burnt area between 1996 and 2008, our results signal a serious cause for concern in the face of continuing global warming.