LPG: Why Do We Think it Might be able to Save Millions of Lives?

Transcription

1 LPG: Why Do We Think it Might be able to Save Millions of Lives? Kirk R. Smith Professor of Global Environmental Health University of California, Berkeley Promoting LPG as an alternative cooking fuel in Sub-Sahara Africa: Stakeholder Meeting 2 December 2014, KfW Frankfurt

2 Bottom Line Incomplete fuel combustion is the enemy Combustion efficiency has to be very high to reduce combustion particles to health guidelines One of the only proven ways to reach near complete combustion in small devices is with gas. Although non-renewable, LPG and other gaseous fuels would not add appreciably to global warming.

3 Declared Biases Speaking as a health scientist Relatively little direct research and policy experience in Africa LPG knowledge dominated by work in India

4 Published In 2005 In spite of its title, this peer-reviewed report covers many issues, including climate

5 Effects of traditional household fuel use Smith et al. Lancet, 2009 Smith, et al. Lancet, 2009

6 Oldest Pollution Source in Human History By definition

7 Woodsmoke is natural how can it hurt you? Or, since wood is mainly just carbon, hydrogen, and oxygen, doesn t it just change to CO 2 and H 2 O when it is combined with oxygen (burned)? Reason: the combustion efficiency is far less than 100%

8 Products of Incomplete Combustion (PIC) PIC PIC Heat

9 Energy flows in well-operating traditional woodfired cookstove PIC = products of incomplete combustion. Wood: 1 kg MJ Traditional Stove Into Pot 2.76 MJ 18% In PIC 1.23 MJ 8% Waste Heat MJ 74% Smith et al., 2000

10 Combustion Efficiency of Cookstoves by Fuel Combustion Efficiency Gas: ` 99% ( ) [18%] Kerosene: 97 (95-98) [7] Solid Fuels Wood: 89 (81-92) [53] Crop resid: 85 (78-91) [10] Dung: 84 (81-89) [10] Coal (variable) [2] Source: Smith, et al, 2000

11 Carbon Balance: A Toxic Waste Factory!! Euculyptus in Indian Vented Ceramic Stove k-factor = (sum of molar ratios to CO 2 ) Typical biomass cookstoves convert 6-20% of the fuel carbon to toxic substances Wood: 1.0 kg 454 g Carbon CO2 Carbon: g PIC Carbon: CO: 18.5 g CH4: 2.8 TNMOC: 5.2 g Char/Ash: 161 g 130 g Carbon TSP Carbon: 1.7 g Nominal Combustion Efficiency = 1/(1+k) = 89%

12 Toxic Pollutants in Biomass Fuel Smoke from Simple (poor) Combustion Small particles, CO, NO 2 Hydrocarbons 25+ saturated Typical hydrocarbons wood such as n-hexane 40+ unsaturated hydrocarbons such as 1,3 butadiene 28+ mono-aromatics cookfire such releases benzene & styrene 20+ polycyclic aromatics such as benzo(α)pyrene 400 cigarettes per hour Oxygenated organics 20+ aldehydes worth including of formaldehyde smoke & acrolein 25+ alcohols and acids such as methanol 33+ phenols such as catechol & cresol Many quinones such as hydroquinone Source: Naeher et al, J Inhal Tox, 2007 Semi-quinone-type and other radicals Chlorinated organics such as methylene chloride and dioxin

13 First person in human history to have her exposure measured doing the oldest task in human history ~5000 ug/m3 during cooking >500 ug/m3 24- hour Emissions and concentrations, yes, but what about exposures? Kheda District, Gujarat, 1981

14 Size Distribution of Biomass Smoke Particles Nearly all smaller Than 2.5 µm Source: Smith, Apte et al. 1984

15 How much PM2.5 is unhealthy? WHO Air Quality Guidelines 10 ug/m3 annual average No public microenvironment, indoor or outdoor, should be more than 35 ug/m3 National standards annual outdoors USA: 12 ug/m3 China: 35 ug/m3 India: 40 ug/m3

16 Definitions Global Burden of Disease (GBD) Envelope of death, illness, and injury by age, sex, and region. Coherent no overlap one death has one cause Comparative Risk Assessment (CRA) The amount of the GBD due to a particular risk factor, e.g. smoking Not coherent deaths can be prevented by several means

17 Basic Principles Like is like The only differences in effects is due to age, not to nation, income, race, social class, sex, etc. All are equal All people have the potential for the highest life expectancy in the world, there are no intrinsic differences by genetic or other reasons.

18 GBD example: Lost life years in Uganda,

19 CRA published along with the other GBD papers on Dec 14, 2012 in The Lancet

20 Household Exposure Measure for CRA Binary metric is possible: use or no use of solid fuels for household cooking and heating: biomass (wood, crop residues, dung) and coal Household survey data available for ~600 nationally representative surveys Model built for whole world

21 The Energy Ladder: Relative Pollutant Emissions Per Meal Biogas LPG Kerosene Wood Roots Crop Residues Dung CO Hydrocarbons PM Smith, et al., 2005 CO Hydrocarbons PM

22 ALRI/ Pneumonia Diseases for which we have epidemiological studies COPD Lung cancer (coal) Lung cancer (biomass) Cataracts Ischemic heart disease Stroke These diseases are included in the 2010 Comparative Risk Assessment (released in 2012)

23 Acute lower respiratory infections (ALRI) Acute Lower Respiratory Infection (ALRI) in a Guatemalan Infant Chief cause of death among the world s children. Thus, it is the chief global cause of lost healthy life years. Tied with diarrhea as second/third after malaria in SS Africa Child mortality occurs almost entirely in developing countries, and as pneumonia. Well-accepted risk factors (malnutrition, micro-nutrient deficiencies, other diseases, crowding, chilling) do not account for its scale.

24 Example: ALRI-HAP Systematic Review and Meta-Analysis Dherani et al. Bull WHO, 2008

25 Integrated Exposure-Response: Outdoor Air, SHS, and HAP Pneumonia from combustion particles Annual average PM2.5 in ug/m3 Annual Incidence Secondhand Tobacco Smoke Outdoor Air Pollution HAP Solid Fuel Zone Zone CRA, 2010

26 Stroke ALRI Lung Cancer COPD Ischemic Heart Disease ug/m3 annual average PM 2.5

27 Global DALYs 2010: Top 20 Risk Factors

28 Global DALYs 2010: Top 20 Risk Factors Premature Deaths HBP -9.3 million Alcohol 7.7 Tobacco 5.7 SHS-T 0.6 House AP 3.6 SHS-C 0.3 High BMI 3.4 Phys Inactive 3.2 Outdoor AP 3.3 High Sodium 3.1

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31 Summary of CRA/GBD for Household Air Pollution 3.6 million premature deaths from direct household exposures 0.3 million more from secondhand cookstove smoke Based on comparison with gas cooking Thus, could be stated as essentially the health impacts of not having cooking gas

32 Details for Uganda

33 % DALYs Attributable to Risk Factors Poor HIV Control Poor Malaria Control Alcohol Use Household Air Pollution Childhood Underweight Iron Deficiency High Blood Pressure Dietary Risks Suboptimal Breastfeeding Poor Vaccination Coverage Occupational Risks Smoking More complete Comparative Risk Assessment for Uganda GBD/CRA leaves out important risk factors High Fasting Plasma Glucose High BMI Physical Inactivity

34 20-month average ground-level PM2.5 from satellite data Non-urban outdoor pollution is substantial Large areas of rural India & China have high ambient air pollution

35 Relative contribution household cookstoves on outdoor particle pollution Chafe, et al., 2014

36 Absolute contribution of household cookstoves on outdoor particle pollution Chafe, et al., 2014

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38 Complete combustion of non-renewable fuels Incomplete combustion of any fuel Why there will be no official BC (or OC) soon. IPCC, AR5, WG1,GWP Fig TS.7

39 IPCC, AR5, WG1, Fig TS.8

40 Smith et al., 2005

41 LPG: 1 kg 825 g Carbon Smith et al., 2005

42 20-year GWPs If only Kyoto GHGs, LPG is roughly equal to renewable wood in traditional stoves Smith, et al., 2005

43 Laws of Carbon-atmospherics I. Keep all fossil and forest carbon out of the atmosphere II. If you cannot do so, the least-damaging form to release is carbon dioxide because all other forms, gas or aerosol, are worse for climate and health. If gases, they eventually turn to CO 2 but are worse than CO 2 until they do III. Even renewable (non-fossil) carbon is damaging for climate and health if not Kirk R. Smith, UC Berkeley released as carbon dioxide.

44 Conclusions It is difficult to burn unprocessed solid fuels completely in simple household-scale devices. Consequently, a large fraction of the fuel carbon is diverted to PIC Leading to inefficient use of the primary resource And, because of the proximity to population, the PIC is responsible for much ill-health in developing countries.

45 Conclusions (cont.) Because the average Global Warming Potential of PIC carbon is greater than CO 2, there is significant global warming commitment per unit energy use for household devices, even when the biomass is harvested renewably. To be greenhouse-gas neutral, therefore, a biomass fuel cycle must not only be based on renewable harvesting, but it also must have good combustion efficiency, i.e., produce little PIC

46 Conclusions The metrics used to compare CAPs Kyoto gases and 100-year time-horizons -- came out of the early 1990s when climate change seemed far off and less certain. Today, however, it seems to be neither, being demonstratably upon us already More emphasis is thus needed to sustainably control shorter-lived CAPs because These can achieve large reductions sooner in RF and, Only their control can affect the rate of as well as the total warming They also exert substantial human health and ecosystem impacts (co-benefits) Products of incomplete combustion -- BC, OC, CO, NMVOCs, however, are difficult to make policy for because They so short lived as to not be globally mixed difficult to treat in same framework as longer lived CAPs, such as CO2 and N2O Their science is still quite uncertain, particularly for aerosols Essentially all control measures affect multiple species at once Kirk R. Smith, UC Berkeley

47 Conclusions, cont. Methane, however, holds a unique niche High RF and large emissions: 2 nd largest total impact after CO2 Largest source of rising global levels of ground-level ozone Relatively short-lived, but long-enough to be globally mixed can be treated under existing framework Two-thirds of its emissions are amenable to control measures using existing technology and policy tools, much at low cost Interventions commonly target methane alone Adding in shorter-lived CAPs shifts the political landscape more responsibility to LDCs in the case of methane, but also Controls in LDCs wield greater leverage for making an impact opportunities are greater and response to them faster than in rich ones Plus, for household combustion, nearly all the health benefits accrue locally to the very poorest and most disenfranchised people on the planet Kirk R. Smith, UC Berkeley

48 3 million tons of methane emissions: ~1% of global total State-wise estimates of 24-h kitchen concentrations of PM2.5 in India Solid-fuel using households Balakrishnan et al. 2013

49 Kind of analysis needing updating quantitative co-benefits Smith & Haigler, 2008

50 Conceptual Indian Energy Ladder Decreasing Household Air Pollution Very Low Income 200 million Low Income 400 million How do we help people move into this realm? Non-solid fuels Wood Kerosene Middle Income 400 million Biogas Coal High Income 200 million Electricity Natural Gas Liquefied Petroleum Gas Crop Waste Dung Solid Fuels Smith/Pillarisetti, 2014 Increasing Prosperity and Development

51 Final Points Products of incomplete combustion from cookstoves cause about 4 million premature deaths annually in poor populations LPG one of the only proven ways to reduce these exposures Climate impact of shifting is low or perhaps even beneficial Not easy, but at least the fuel is always clean Kirk R. Smith, UC Berkeley

52 Many thanks Publications and presentations on website easiest to just google Kirk R. Smith