VIETNAM NATIONAL UNIVERSITY, HANOI VNU UNIVERSITY OF SCIENCE FACULTY OF ENVIRONMENTAL SCIENCE BLACK CARBON EMISSION FROM RICE STRAW OPEN BURNING IN SOME PROVINCES OF THE RED RIVER DELTA Supervisor: Assoc.Prof.Dr Hoang Xuan Co Student: Vu Thi Hanh1 INTRODUCTION • • • • Black Carbon (BC) One of the Short-live Climate Forcer The second most important contributor to global warming Having negative impacts on climate, public health, agriculture and ecosystem The RRD is the second most important rice-producing area in Vietnam; rice cultivation generates huge amounts of rice straw Burning rice straw in the field becomes a popular activity  main source of BC aerosol and directly effect on local air quality Method to estimate or measure BC emission are neccesary 2 Contents: Chapter 1: Overview • • • 1.1 Black Carbon 1.2 Study area 1.3 Rice straw burning in the field Chapter 2: Objects and Methodology • • 2.1 Objects to study 2.2 Methodology Chapter 3: Results and Discussions • • • • • 3.1 Summary data acquistion 3.2 Estimate Black Carbon emission 3.3 Compare the results of the two approaches 3.4 Measurement of Black Carbon 3.5 Solution to reduce rice straw open burning 3 Chapter 1 4 1.1 Black carbon • • Production of incomplete combustion Consisting of soot, charcoal, and possible light-absorbing refractory organic matter • Having short atmospheric lifetime  One of the short-lived climate forcers Source: US EPA Transmission electron microscopy image of a representative soot particle 5 1.1 Black Carbon 1.1.2 Sources of Black Carbon • Natural sources: include erupting volcanoes, wildfires Erupting volcanoes Wildfire 6 • Anthropogenic sources: Biomass open burning Residential cooking Source: US EPA Industrial process Transportation 7 1.1 Black Carbon 1.1.3 Physical properties • Strongly absorption of visible light • Refractory • Insoluble in water and organic solvents • Aggregate of small carbon spherules  BC is very distinctive Source: Bond et al, 2013 Black Carbon aggregates 8 1.1 Black Carbon 1.1.4 Impacts of BC  Climate impacts: - Direct radiative forcing: Change in the energy balance due to absorption and scattering of sunlight -Interactions with clouds: + Changing cloud distributions + Changing the number concentration of liquid cloud droplets -Snow/ice albedo effect: Reduced albedo  Increases surface melting -Other impacts: Change in precipitation patterns  Change surface dimming Source: T.C Bond BC direct radiative forcing 9 1.1 Black Carbon  Health public impacts - BC visibility associated with PM2.5 Result in millions of premature deaths worldwide, including: + Aggravation of respiratory + Cardiovascular disease + Impaired lung function + Changes in heart rhythm - Reducing BC can prevent 640,000 to 4,900,000 premature deaths every year  Agriculture and ecosystem impacts: - Reduce agricultural production - Affect ecosystems’ carbon uptake - Affect metabolic processes of foliage 10 Methodology Measurement BC concentration • Data is saved automatically for 5 minutes for 7 days from 20th to 26th of October This time is the period after harvesting of suburban districts • Meteorological factors such as wind direction, wind speed, temperature, humidity, pressure was also measured at the same time 21 Methodology Field survey method • Asked about the situation of agricultural production, using RS of some households and officials People's Committees of communes • Visited some models that use rice straw to grow mushrooms and feed redworms 22 Chapter 3 23 3.1 Summary data acquistion Table Production of paddy and average rural population by province in 2013 Ha Noi Vinh Phuc Ninh Binh 1156.3 308.7 460.9 3985.5 785.6 749.7 Production of paddy (thous.tons) Rural population (thous.persons) Table Production of paddy and average rural population by commune in 2013 Tho Xuan Ngoc Thanh Gia Xuan 842759 4503285 1219062 9710 12317 3967 Production of paddy (kg ) Rural population (persons) 24 3.2 Estimate BC emission Table Production of rice straw burning in the filed by commune Unit: kg/ha Commune Fraction of rice straw that are burned in the field (%) 30 40 50 60 70 80 90 Tho Xuan 227604 303472 379341 455209 531077 606945 682813 Ngoc Thanh 1216204 1621606 2027007 2432409 2837810 3243212 3648613 Gia Xuan 329233 438977 548721 658465 768210 877954 987698 Table Production of rice straw burning in the filed by province Unit: thous tons Commune Ha Noi Vinh Phuc Ninh Binh Fraction of rice straw that are burned in the field (%) 30 40 50 60 70 80 90 0.312 0.416 0.520 0.625 0.729 0.833 0.937 0.083 0.111 0.139 0.167 0.194 0.222 0.250 0.125 0.166 0.208 0.249 0.291 0.332 0.374 The best etimation for fraction burned in the fields is 80% in Hanoi, 60% in Vinh Phuc, and 50% in Ninh Binh 25 3.2 Estimate BC emission Approach 1: Use BC emission per capita of commune Table Annual BC emission from RSOB by commune in 2013 Unit: g/year Fraction of RS that are burned in the field (%) Commune 30 40 50 60 70 80 90 Tho Xuan 116078 154771 193464 232156 270849 309542 348235 Ngoc Thanh 620264 827019 1033774 1240529 1447283 1654038 1860793 Gia Xuan 167909 223878 279848 335817 391787 447756 503726 Table BC emission per capita by commune in 2013 Unit: g/person/year Fraction of RS that are burned in the field (%) Commune 30 40 50 60 70 80 90 Tho Xuan 11.95 15.94 19.92 23.91 27.89 31.88 35.86 Ngoc Thanh 50.36 67.14 83.93 100.72 117.50 134.29 151.08 Gia Xuan 42.33 56.44 70.54 84.65 98.76 112.87 126.98 26 3.2 Estimate BC emission Approach 1: Use BC emission per capita of commune Table Annual BC emission from RSOB by province in 2013 Unit: Gg/year Fraction of RS that are burned in the field (%) Province 30 40 50 60 70 80 90 0.048 0.064 0.079 0.095 0.111 0.127 0.143 Vinh Phuc (785.6) 0.040population of province 0.053 in 2013 (thous.persons), 0.066 Note: Values in brackets () are rural 1Gg = 10 90.079 g 0.092 0.105 0.119 0.074 0.085 0.095 Ha Noi (3985.5) Ninh Binh 0.032of paddy by province 0.042 Approach 2: (749.7) Use total production 0.053 0.063 Table Annual emission of BC from RSOB by province in 2013 Unit: Gg/year Fraction of rice straw that are burned in the field (%) Province 30 40 50 60 70 80 90 Ha Noi 0.159 0.212 0.265 0.319 0.372 0.425 0.478 Vinh Phuc 0.043 0.057 0.071 0.085 0.099 0.113 0.128 Ninh Binh 0.064 0.085 0.106 0.127 0.148 0.169 0.191 27 3.3 Compare the results of the two approaches Figure BC emission in three provinces for two approaches The difference between two approaches due to the homogeneity of the communes in the province, including structure of agriculture, RS fraction burned in the fields and rural population 28 3.4 Measurement of BC concentration - Average concentration of BC in Ha Noi is 5.03µg/m3, the highest concentration reaches 16.1µg/m3 - BC concentration in Hanoi is rather higher than the one in some urban area of developed countries + United State: 0.3-3.0 µg/m3 (2007) + Canada: 0.9-1.8 µg/m3 (2003-2009) + United Kingdom: 1.0-2.9 µg/m3(2009) ( Source: US EPA) Figure Average hourly concentration of BC - Wind blows, especially from Northwest (Hoai Duc, Dan Phuong, Dong Anh) and Southeast (center of Ha Noi city)  High BC concentrations in measurement point 29 3.5 Solutions to reduce rice straw burning in the field Growing mushroom Composting organic fertilizers Rice straw Energy production Feeding redworms 30 3.5 Solutions to reduce rice straw burning in the field • Using rice straw for growing mushrooms in Tho Xuan - Production is estimated 200 tons/year - Waste of mushroom use for growing fresh vegetables as organic fertilizers Use approximately 20-30 tons of rice straw and other residues 31 3.5 Solutions to reduce rice straw burning in the field • Using RS for feeding redworms of Ms Nguyen Thi Nga - Rice straw and waste materials are decomposed by microorganisms  Source of nutrition for redworms - Waste of redworms used to grow fresh vegetables, fruit trees, fish and chicken 32 Conclusions and recommendations 1 Conclusions • Estimation of BC emission from RSOB - RSOB is a popular activity in the rice-growing areas - The best estimation of BC emission: + In approach 1: 0.127 Gg/year for Ha Noi, 0.079 Gg/year for Vinh Phuc and 0.066 Gg/year for Ninh Binh + In approach 2: 0.425 Gg/year in Ha Noi, 0.085 Gg/year in Vinh Phuc and 0.106 Gg/year in Ninh Binh - The difference between two approaches due to the homogeneity of communes in the province - Uncertainty: + Residue to rice ratio, biomass density, burning efficiencies, and emission factors are not available for Vietnam + Fraction of RS that are burned in the fields was not investigated for each region 33 1 Conclusion • BC concentration in Hanoi - The average BC concentration in Ha Noi is 5.03 µg/m3, highest concentration reaches 16.1 µg/m3 - BC concentration in Hanoi is rather higher than the one in some urban area of developed countries - High BC concentrations in Hanoi may be affected by biomass open burning and transportation 34 2 Recommendation - Further research focuses on the measurement these parameters of emission factors, crop residue to crop ratio, fraction burned of crops at the field, biomass density, burning efficiency for rice and other crops - Emission per capita and fraction burned should be calculated for each commune in province to avoid uncertainty from homogeneity between communes - Monitor and measurement should be encouraged to compare between real data and estimation data To reduce BC emission from RS burning, it is necessary to develop a better management system to cutting or reducing crops residue open burning, including RS Further study about local condition to have suitable and sustainable methods for each region 35