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Household Air Pollution Risks in India Kirk R. Smith, MPH, PhD Professor of Global Environmental Health University of California, Berkeley Fulbright-Nehru Distinguished Chair IIT-Delhi. The Environmental Health Pathway. 1.8 million years ago, the cooking became
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Household Air Pollution Risks in IndiaKirk R. Smith, MPH, PhDProfessor of Global Environmental HealthUniversity of California, BerkeleyFulbright-Nehru Distinguished ChairIIT-Delhi
1.8 million years ago, the cooking became a regular feature in human society Catching Fire: How Cooking Made Us Human, R Wrangham Basic Books, 2009
Population Cooking with Solid Fuels in 2010 (%) Leading cause of disease burden in 2010 by country
1990: 85%: 700 million people using solid fuels 2010: 60%: 700 million people ~1980 700 million people in entire country 700 million people in the Chulha Trap
Woodsmoke is natural – how can it hurt you? Or, since wood is mainly just carbon, hydrogen, and oxygen, doesn’t it just change to CO2 and H2O when it is combined with oxygen (burned)? Reason: the combustion efficiency is far less than 100%
A Toxic Waste Factory!! Typical biomass cookstoves convert 6-20% of the fuel carbon to toxic substances Energy flows in a well-operating traditional wood-fired cookstove 15% moisture Source: Smith, et al., 2000 PIC = products of incomplete combustion = CO, HC, C, etc.
Toxic Pollutants in Biomass Fuel Smokefrom Simple (poor) Combustion • Small particles, CO, NO2 • Hydrocarbons • 25+ saturated hydrocarbons such as n-hexane • 40+ unsaturated hydrocarbons such as 1,3 butadiene • 28+ mono-aromatics such as benzene & styrene • 20+ polycyclic aromatics such as benzo()pyrene • Oxygenated organics • 20+ aldehydes including formaldehyde & acrolein • 25+ alcohols and acids such as methanol • 33+ phenols such as catechol & cresol • Many quinones such as hydroquinone • Semi-quinone-type and other radicals • Chlorinated organics such as methylene chloride and dioxin Typical chullah releases 400 cigarettes per hour worth of smoke Source: Naeher et al, J Inhal Tox, 2007
TypicalHealth-based Standards TypicalIndoor Concentrations IARC Group 1 Carcinogens Best single indicator Health-Damaging Air Pollutants From Typical Wood-fired Cookstove.
First person in human history to have her exposure measured doing the oldest task in human history Emissions and concentrations, yes, but what about exposures? ~5000 ug/m3 during cooking >500 ug/m3 24-hour Kheda District, Gujarat, 1981
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
CRA published along with the other GBD papers on Dec 14, 2012 in The Lancet
Annual Review of Public Health, vol 35, 2014, out this month
Comparative Risk Assessment Method Exposure-response Relationships (risk) Exposure Levels: Past actual and past counterfactual Disease Burden by age, sex, and region Attributable Burden by age, sex, and region
State-wise estimates of 24-h kitchen concentrations of PM2.5 in India Solid-fuel using households Balakrishnan et al. 2013 (SRU group)
COPD ALRI/ Pneumonia Lung cancer (coal) Lung cancer (biomass) Cataracts Ischemic heart disease Stroke Diseases for which we have epidemiological studies These diseases are included in the 2010 Comparative Risk Assessment (released in 2012)
New Category of Evidence for CVD • No direct studies of CVD and HAP, yet • But studies showing effects on blood pressure and ST-segment, important disease signs • Epidemiologic evidence shows clear, consistent evidence of increasing risk across exposures to combustion particles • at higher exposures – Active smoking • and lower exposures – Outdoor air pollution and secondhand tobacco smoke
Heart Disease and Combustion Particle Doses From “Mind the Gap,” Smith/Peel, 2010 and Pope et al., 2009 HAP Zone
Smokers Secondhand Tobacco Smoke Outdoor Air Pollution HAP Zone Integrated Exposure-Response: Outdoor Air, SHS, and Smoking and Heart Disease CRA, 2011
EHP, 2007 EHP, 2011 EHP, 2011
Secondhand Tobacco Smoke Outdoor Air Pollution Solid Fuel Zone HAP Zone Integrated Exposure-Response: Outdoor Air, SHS, and HAP CRA, 2010
Stroke ALRI COPD Ischemic Heart Disease Lung Cancer ug/m3 annual average PM2.5
Metrics • Mortality – important, but can be misleading as it does not take age into account or years of illness/injury • Death at 88 years counts same as at 18, which is not appropriate • Disability-adjusted Life Years (DALYs) lost do account for age and illness. • GBD 2010 compares deaths against best life expectancy in world – 86 years
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 – 3.5 SHS-C – 0.5 High BMI – 3.4 Phys Inactive – 3.2 Outdoor AP – 3.3 High Sodium – 3.1
Top 15 causes of ill-health in India (GBD/CRA 2010)HAP Total: ~1,000,000 premature deaths annually Women and Girls Men and Boys:
Framing • Not called “indoor” because stove smoke enters atmosphere to become part of general outdoor air pollution (OAP) • HAP contributes about 12% to OAP globally, but much more in some countries • ~25% in India • Thus, part of the burden of disease due to OAP is attributable to cooking fuels in households
%PM2.5 from “Residential” Emissions from INTEX_B 25-30% of primary particle pollution in India is from household fuels Source: Asian Emission Inventory for NASA INTEX_B 2006 (accessed 2010) 36 Chafe, 2010
Satellite-based ambient PM2.5 van Donkelaar et al, EHP 2010
Rural India 24h mean PM2.5: 194.7 µg/m3
HAP mortality in India in 2010 ~10 lakh annual premature deaths -About one-quarter of global total -Secondhand cooksmoke ~1,5 lakh more -About 10% of national mortality -About the same as tobacco -About 50% more than outdoor air pollution, which is about 600k n.b. these estimtes can be compared but not added as there are overlaps
Summary • One of the top risk factors in the world for ill-health. • Biggest impact in adults --3 million premature deaths (two-thirds the DALYs) • Still important for children ~500,000 deaths (one-third the DALYs) • One million total premature deaths in India • Biggest single risk factor of any kind for Indian women and girls • Important source of outdoor air pollution • Impact going down slowly because background health conditions improving • Actual number of people affected is not going down
Conceptual Indian Energy Ladder Very Low Income 200 million Low Income 400 million Middle Income 400 million High Income 200 million Electricity Natural Gas Liquefied Petroleum Gas Biogas Kerosene Decreasing Household Air Pollution Non-solid fuels Coal Wood Crop Waste Dung Solid Fuels Increasing Prosperity and Development
“Clean”“Dirty” Smith, et al., 2005
Conceptual Indian Energy Ladder Very Low Income 200 million Low Income 400 million Middle Income 400 million High Income 200 million Electricity Natural Gas Liquefied Petroleum Gas Biogas ? ? Kerosene Decreasing Household Air Pollution Non-solid fuels Coal Wood Crop Waste Dung Solid Fuels Increasing Prosperity and Development
Integrated Exposure-response relationship Child pneumonia Starting here Risk Going here 3 WHO air quality annual guideline: 10µg/m3 IT1 : 35 µg/m3 Leaves ~80% of burden untouched 2 Can we get here? PM2.5 Exposure 1 LPG Rocket ‘Chimney O/Fire Fan 25 125 200 300 µg/m3
How close to clean enough? • New WHO Indoor Air Quality Guidelines will be about 0.9 mg/min PM2.5 to protect ~80% of households at AQG-IT1, 35 ug/m3 • Cleanest biomass blower stove tested by the USEPA is about 8 times more polluting in lab. • But does not achieve this over time in the field • Need to push harder to find ways to make biomass burn cleanly in inexpensive devices
Secretary Vivek Rae • Doubled number of distributors for next year --20 million new people • Brought together heads of marketing for the 3 major oil companies to hear the lecture • Had his staff do the homework in advance • By adjusting requirements for distributors and a massive push • They are developing a plan to double LPG access in rural India in next five years • ~250 million people
Conceptual Indian Energy Ladder Very Low Income 200 million Low Income 400 million Middle Income 400 million High Income 200 million Electricity Natural Gas ? Liquefied Petroleum Gas Biogas Kerosene Decreasing Household Air Pollution Non-solid fuels Coal Wood Crop Waste Dung Solid Fuels Increasing Prosperity and Development