Smoke gets in your lungs Assoc Prof Peter Franklin University of Western Australia Environmental Health Directorate, EHD
Conflict of Interest
Conflict of Interest I have an open fireplace
Wood smoke is it a problem? woodsmoke, being a natural substance, is sometimes considered benign to humans. It is now well established, however, that wood-burning stoves and fireplaces as well as wildland and agricultural fires emit significant quantities of known healthdamaging pollutants, including several carcinogenic compounds
Chemical composition of wood smoke Chemical g/kg Wood Chemical g/kg Wood carbon monoxide 80-370 chlorinated dioxins 1x10-5 - 4x10-5 methane 14-25 normal alkanes (C24-C30) 1x10-3 - 6x10-3 VOCs* (C2-C7) 7-27 magnesium 2x10-4 - 3x10-3 aldehydes 0.6-5.4 aluminum 1x10-4 - 2.4x10-2 substituted furans 0.15-1.7 silicon 3x10-4 - 3.1x10-2 benzene 0.6-4.0 sulfur 1x10-3 - 2.9x10-2 alkyl benzenes 1-6 chlorine 7x10-4 - 2.1x10-2 acetic acid 1.8-2.4 potassium 3x10-3 - 8.6x10-2 formic acid 0.06-0.08 calcium 9x10-4 - 1.8x10-2 nitrogen oxides 0.2-0.9 titanium 4x10-5 - 3x10-3 sulfur dioxide 0.16-0.24 vanadium 2x10-5 - 4x10-3 methyl chloride 0.01-0.04 chromium 2x10-5 - 3x10-3 napthalene 0.24-1.6 manganese 7x10-5 - 4x10-3 substituted napthalenes 0.3-2.1 iron 3x10-4 - 5x10-3 oxygenated monoaromatics 1-7 nickel 1x10-6 - 1x10-3 total particle mass 7-30 copper 2x10-4 - 9x10-4 particulate organic carbon 2-20 zinc 7x10-4 - 8x10-3 oxygenated PAHs 0.15-1 bromine 7x10-5 - 9x10-4 Individual PAHs 1x10-5 - 1x10-2 lead 1x10-4 - 3x10-3
Selected chemicals and their Component PM (organic and black carbon) Carbon Monoxide Ozone Nitrogen and sulphur based compounds Hydrocarbons Volatile organic compounds Phenols Quinone effects Main health effect Heart and lung morbidity and mortality Hypoxia Respiratory irritant Respiratory irritants Mutagens, carcinogens, irritants, neurotoxins Mutagens, carcinogens, irritants, neurotoxins Irritant, mutagenic, carcinogenic Irritant, allergenic, oxidative stress Source: Johnston, Woodsmoke presentation, EPA Tas, 2013
Biomass burning and particulates Any biomass burning (inc wood) creates high volume of particulate matter (PM) Number of particles will depend on; Type of wood Moisture content Burn phase Particulates from wood fires are predominantly extremely small (diameter range 30 300 nm*) PM thought to be the best single indicator of the health impacts of most combustion sources. * nm = 10-9
PM Emission factors mass of PM/weight of oven dry fuel Varies with type of wood Burn rate Moisture content Heater Burn rate Fuel Emission factor (g/kg) Heater A High Eucalypt 1.0 (± 0.6)* High Pine 0.7 (± 0.3)* Medium Eucalypt 1.9 (± 0.8)* Medium Pine 2.1 (± 0.7)* Low Eucalypt 6.0 (± 2.5)* Low Pine 18.2 (± 10.9)* Heater B High Eucalypt 7.9 (± 3.0)* High Pine 6.4 (± 3.3)* Medium Eucalypt 8.5 (± 1.4)* Medium Pine 9.6 (± 2.4)*
Source: Consultation regulation impact statement for reducing emissions from wood heaters, 2013
Contribution of wood fires to urban PM Figure 3.1: Wood heater contribution to total PM10 emissions, 2008-09 100% 80% 60% 40% 20% 0% Canberra Launceston Perth Port Phillip Sydney GMR Woodheaters Other diffuse sources Industry
Wood smoke and air quality
Wood smoke and air quality
Lung deposition of particulate matter Inhalable: anything that can be inhaled in the mouth or nose during normal breathing (50% @ 100 µm PM 100 ) Thoracic: the aerodynamic particle diameter for 50% penetration into the thorax is 10 µm (PM 10 ) Respirable: particles that can penetrate through the conductive airways of the tracheobronchial tree to the gas-exchange airways in the lungs. Cut-size PM 4 Systemic: Smaller particles (< PM1) can be absorbed into the bloodstream * Woodsmoke predominantly <PM1
lung disease, heart disease Aggravate asthma and other respiratory disease
Respiratory effects of PM Table: Respiratory effects for 10 µg/m 3 increase in PM Mortality increase Total: 1% Respiratory: 3% Hospital admissions ands visits Any respiratory: 1% Asthmatics: 3% Other associations Asthma attacks: +3% URT symptoms: +0.7% Cough: +2% Lung function: -0.1% LRT symptoms: +3% Lung function growth Lung function decline
Cardiovascular effects of PM
Concentration-response relationship There is no clear safe threshold for particulate air pollution Linear, no threshold C-R relationship Outcomes are worse for those with pre-existing disease
PM and health: is there a causal relationship?
Domestic wood smoke and health How do we know? Biological plausibility Coherence with other combustion particles Controlled exposures Epidemiology Bushfires Outdoor air pollution Intervention studies Indoor biomass burning
Controlled exposures 4 studies PM 240 660 μg/m 3 2 4 hours Some evidence of; markers of airway inflammation blood markers of inflammation markers of oxidative stress markers of coagulation Mild symptoms only No change in lung function Laboratory set-up for controlled wood fire exposure (Sallsten et al., Inhal Tox 2006; 18: 855)
Bushfires Data from bushfire studies suggest there is no reason to think that the adverse impacts of acute woodsmoke exposure would be less than those associated with other sources of ambient PM Data is consistent for respiratory symptoms but not as strong for cardiovascular effects Short-term effects only
Residential woodsmoke Mostly derived from studies where woodsmoke is major contributor to urban PM High v low wood smoke areas Heating v non-heating seasons Time-series studies in high wood smoke areas Main health outcomes wheeze in young children lung function in asthmatic children ED visits and hospitalization in asthmatic children daily mortality all-cause ED visit (data not consistent)
Case-study Christchurch NZ ~80-90% of PM pollution in ChCh is due to residential wood smoke 10µg/m 3 of PM 10 exposure = 3.4% increase in respir admissions 1 1.3% increase in cardiac admissions 1 7% increase in all deaths 2 1 McGowan J, et al. Particulate air pollution and hospital admissions in Christchurch, NZ. ANZJPH 2002; 26: 23 9. 2 Fisher G, et al. Health and Air Pollution in New Zealand, Final Report: Health Research Council of New Zealand & Ministry for the Environment & Ministry of Transport, 2007.
Background >80% of PM pollution due to residential wood smoke 4,200 households 1100 old woodheaters replaced Low emission wood stoves + other Results (children only) 28% PM2.5 25% cold 55% bronchitis 52% influenza 45% throat infection 30% wheeze Intervention studies Study 1: Libby, Montana
Background Intervention studies Study 2: Launceston, TAS 66% homes use wood heaters ~85% PM from wood heaters Education program starting 1994 Wood heater use to 30% Improved operation of others Results Mean winter PM10 44 g/m 3 (1994 2000) to 27 g/m 3 (2001 2007) Annual all-cause mortality in males 11.4% No change in females
Indoor biomass burning IAP from biomass cooking assoc with; lung cancer, asthma, ARI, TB, cataracts, still births, low birth weight, early infant death 1 mill prem deaths - 2.7% global burden of disease *2nd biggest environmental contributor to ill health, behind unsafe water and sanitation
Quantifying the burden of PM Direct costs Mortality Hospitalisation Indirect costs Medication lung function Reduced productivity Welfare Home modification Intangible costs Stress Family pollution Table: Increases in direct health outcomes as a result of PM pollution Health outcome % per 10 g/m 3 Premature mortality (adults) Premature mortality (infants) 7.0% (3.0 10.0) 5.0% (2.0 8.0) Admissions (resp) 1.0% (0.6 1.7) Admissions (CV) 0.6% (0.3 0.9) RADs 0.9% (0.5 1.7)
Cost-Benefit Analysis of Wood Smoke Reduction in Perth (Todd, Nov 2005) 16 premature deaths each year, 1 extra infant death every 5 years, 4 extra cases of lung cancer, 905 extra hospital admissions, and 73,000 extra reduced activity days.
Consultation regulation impact statement for reducing emissions from wood heaters (2013)
CRIS 2013
Summary Wood smoke impacts both local (neighbourhood) and regional ambient air quality Wood smoke is not benign and contains many toxic gases and aerosols (will vary with type and moisture of wood) PM main marker for health effects Wood smoke affects respiratory (and possibly cardiovascular) health in a similar manner to other combustion sources Woodsmoke reduction interventions have noticeable beneficial effects on health