SUPPLEMENTARY INFORMATION DOI: 10.1038/NCLIMATE1325 Increased estimates of air-pollution emissions from Brazilian sugar-cane ethanol Tsao, C.-C. 1, Campbell, J.E. 1*, Mena-Carrasco, M. 2, Spak, S.N. 3, Carmichael, G.R. 3, Chen, Y. 1 1 School of Engineering, University of California, Merced. 2 Department of Environmental Engineering, Universidad Andres Belo, Santiago. 3 Center for Global and Regional Environmental Research, University of Iowa, Iowa City. Supplementary Methods Monthly Allocation Factors (MAF) In the farming and field burning phases, MAF m,f is the monthly cultivation ratio of sugarcane crops, which is calculated by dividing the average sugarcane harvest in the next ten months by the total production due to the average 10-month-growth period of sugarcane. The monthly quantity of sugarcane harvested and crushed in Brazil is obtained from the USDA FAS 1. The activities of the burning and refinery phases follow the same temporal scaling. MAF m,t, the monthly ratio of ethanol distributed, is assumed to be evenly allocated over the 12 months in a year due to year-round demand. Emission Factors (EF) Emission factors (EF i,p ) of 6 regulated air pollutants in each phase of the sugarcane ethanol life-cycle are obtained from the Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET) model 2. The formulation of emission factors (per Mg sugarcane yield) for the field burning phase in the GREET model are based on emission factors of biomass burning (per kg dried matter burned) synthesized from IPCC and Andreae et al. s work, and the estimation NATURE CLIMATE CHANGE www.nature.com/natureclimatechange 1
of sugarcane residue yield in an official report of sugarcane ethanol assessment prepared for Brazilian government 3. The residue yield is 0.140 Mg dried matter of trash per Mg sugarcane produced with 80% of cane burned (resulting in 0.112 Mg dried matter burned per Mg sugarcane). Mechanized harvesting of sugarcane in São Paulo state has allowed for a reduction in burning. Both agriculture survey data and Landsat studies for São Paulo state suggest that the use of burning as a management practice has been reduced to 50% of sugarcane cropland area in 2008 4,5. We apply the survey data for the burning practice rates in São Paulo state and assume 100% of the areas are burned in other states.
Supplementary Table S1. State-level life-cycle emission of ethanol in Brazil, 2008 (Unit: MT/yr) State VOC NOX PM10 PM2.5 SOX CO CO2 BC 1 OC 2 COS 3 ACRE 106 87 18 9 1 2,321 229,284 0 0 0 RONDONIA 303 238 122 61 11 5,977 539,784 10 49 1 AMAZONAS 778 608 333 166 31 15,177 1,354,648 29 140 3 PARÁ 1,636 1,279 693 346 64 31,991 2,861,294 61 290 6 TOCANTINS 236 189 77 39 7 4,836 451,353 5 26 1 MARANHÃO 2,434 1,758 1,930 957 196 39,459 2,809,833 220 1,053 21 PIAUÍ 1,061 776 779 386 78 17,762 1,325,044 87 416 8 CEARÁ 1,403 1,141 317 161 24 29,940 2,899,503 12 57 1 R. G. NORTE 2,505 1,720 2,547 1,260 264 35,537 1,989,515 308 1,472 29 PARAIBA 4,314 2,920 4,653 2,301 485 58,821 3,001,191 569 2,719 54 PERNAMBUCO 13,365 8,969 14,891 7,363 1,555 177,905 8,529,385 1,831 8,755 172 ALAGOAS 17,773 11,700 21,210 10,483 2,225 223,840 9,076,521 2,638 12,617 249 SERGIPE 1,473 1,016 1,470 727 152 21,160 1,216,025 177 846 17 BAHIA 3,888 2,928 2,349 1,168 231 69,694 5,671,979 246 1,174 23 MINAS GERAIS 30,003 20,139 33,389 16,509 3,487 399,715 19,208,958 4,104 19,626 387 ESPIRITO SANTO 3,310 2,255 3,474 1,719 361 45,992 2,455,915 422 2,020 40 RIO DE JANEIRO 5,040 3,717 3,528 1,751 354 85,963 6,574,114 388 1,857 37 SÃO PAULO 124,383 112,396 156,221 76,555 22,434 1,512,931 91,561,414 16,726 79,994 1,576 PARANÁ 30,034 19,913 34,962 17,282 3,662 386,210 16,753,412 4,331 20,711 408 SANTA CATARINA 950 782 159 82 10 20,773 2,052,291 0 0 0 R. G. SUL 1,733 1,415 362 184 27 37,255 3,629,456 10 50 1 MATO GROSSO 10,134 6,702 11,901 5,883 1,247 129,358 5,483,574 1,476 7,061 139 MATO GROSSO DO SUL 11,815 7,784 14,057 6,948 1,475 149,175 6,101,183 1,748 8,358 165 GOIÁS 19,971 13,276 23,032 11,386 2,411 258,767 11,487,701 2,848 13,623 268 Brazil (Total) 288,645 223,707 332,472 163,727 40,794 3,760,558 207,263,378 38,245 182,913 3,603 1 : Black carbon (BC) 2 : Organoc carbon (OC) 3 : Carbonyl Sulfide (COS)
Supplementary Table S2. Summary of emissions and emission ratio from 5 life-cycle phases for São Paulo State, 2008 (Unit: MT/yr) Unit Life-cycle Farming Field Burning Refinery T/D Vehicle VOC 2,293 (1.8%) 101,204 (81.4%) 13,384 (10.8%) 1,055 (0.8%) 6,448 (5.2%) 124,383 NO X 15,449 (13.7%) 36,144 (32.2%) 31,724 (28.2%) 23,772 (21.2%) 5,307 (4.7%) 112,396 PM 10 PM 2.5 1,466 (0.9%) 112,769 (72.2%) 40,151 (25.7%) 753 (0.5%) 1,081 (0.7%) 156,221 744 (1.0%) 56,388 (73.7%) 18,341 (24.0%) 527 (0.7%) 555 (0.7%) 76,555 SO X 3,676 (16.4%) 5,786 (25.8%) 1,487 (6.6%) 11,415 (50.9%) 69 (0.3%) 22,434 CO 5,577 (0.4%) 1,330,114 (87.9%) 31,724 (2.1%) 4,483 (0.3%) 141,033 (9.3%) 1,512,931 Supplementary Table S3. Major municipalities of field burned in São Paulo state, 2008 by this approach and CANASAT data. This Study CANASAT a Municipality Burned area (ha) % of São Paulo burned area Burned area (ha) % of São Paulo burned area Ribeirão Preto 695,274 31% 530,637 28% Bauru 283,853 13% 203,435 11% São José do Rio Preto 242,585 11% 312,643 16% Araraquara 201,022 9% 153,529 8% a: Data based on Rudorff et al. (2010) 5
IPCC GFEDv3.1 d FINN e Supplementary Table S4. Emission factors (g emitted/ kg DM) of sugarcane or agriculture biomass burning applied in this study and in satellite based approaches. This study a Jenkins b Andrea and Merlet. c CO 92 24.48 92±84 -- 94 70 NOx 2.5 2.06 2.5±1.0 2.5±1.0 2.29 2.4 SOx f 0.4 0.62 0.4 -- 0.4 0.4 g PM 10 7.8 5.4 13 -- 12.4 e 6.9 PM 2.5 3.9 5.0 3.9 -- 8.25 5.7 VOC 7.0 -- 7.0 -- 11.19 7.0 OC 3.3 -- 3.3 -- 3.71 3.3 BC 0.69 -- 0.69±0.13 -- 0.48 0.69 COS 0.065 -- 0.065±0.077 -- -- -- a : Emission factors from GREET are based on Andrea and Merlet (2001). b : Emission factors from sugarcane burning experiments 6. c : Emission factors for biomass burning from agriculture open burning 7. d : Based on Andreae and Merlet (2001) and personal communication 8. e : Based on Dennis et al. (2002), Andreae and Merlet (2001), Jenkins (1996), and EPA AP-42 document (1995) 9. f : as SO 2 g : as TPM
Supplementary Figure S1. Emission of PM 2.5 and CO in different phases for July 2008 including (a) Field burning (b) Farming (c) Refinery (d) Transportation and distribution (e) Vehicle combustion phase.
Supplementary Figure S2. Emission of 5 air pollutants (a) VOC (b) NO X (c) PM 10 (d) PM 2.5 (e) SO X (f) CO in January and July, 2008.
Supplementary Figure S3. Comparison of monthly PM2.5 emission in August 2008 (a) Sugarcane field burning emissions estimated by our bottom-up approach; (b) FINN; (c) GFEDv3.1; and (d) GFEDv3.1-Ag. Supplementary Figure S4. Difference of bottom-up and other emission estimates in August 2008: (a) bottom-up minus GFEDv3.1; (b) bottom-up minus FINN.
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