Air Pollution Background • A widely recognized problem in developed and developing nations • Definition: the presence of substances in air at concentrations, durations and frequencies that adversely affect human health, human welfare or the environment. • Humans suffered from blackening of lung tissue through long exposure to particulate air in smoky dwellings going back to ancient times. • Unhealthy air was the suspected cause of disease long before the relationship could be scientifically confirmed.
Air Pollution and Health • A major environmental risk to health • Exposure: inhaled aerosols (particles) and gases • Estimated to cause ca. 2 million premature deaths worldwide/year • Exposure is largely beyond the control of individuals – But individuals can reduce household emissions and exposures • Requires action by public authorities at national, regional and international levels.
Air Pollution and its Sources • Major pollutants: – Ozone – Sulfur dioxide – Oxides of nitrogen – Particles or particulates – Carbon monoxide – Volatile organic compounds – Trace metals Clean Air Mobile Source Stationary Air Pollution Sources & Pollutants
Particles Sizes and Airborne Agents
Respiratory System and Air Pollutants Particles: >100 µM contact eyes, nose and throat; can be irritants >20 µM are inhaled but do not penetrate below the throat < 10 µM enter airways and may be deposited in respiratory system <2. 5 µM deposit in alveoli with high efficiency (fine particles) < 0. 1 µM remain suspended to be breathed out again
US EPA Regulated Particulates • Total Suspended Particulate Matter (TSP) – 0. 1 - 30 micrometer in diameter • PM 10 – aerodynamic diam. ≤ 10 micrometers – penetrate into lower respiratory tract; 0. 1 and 10 micrometers size range is especially important • PM 2. 5 – aerodynamic diam. of less ≤ 2. 5 micrometers – airborne for several hours to days; long distance travel – Human respiratory system vulnerable from exposure to them – Composed of sulfates, nitrates, organic cds. , ammonium cds. , acidic materials, metals & other contaminants causing adverse health effects. – 0. 2 to 0. 5 micrometer: common in combustion, waste incineration, and metallurgical sources – 0. 1 to 1. 0 micrometers: significant emissions from industrial sources
US EPA Regulated Particulates, Continued • Particles less than 0. 1 micrometer diam. – Combustion and metallurgical sources generate 0. 01 to 0. 1 micrometer particles. – Tend to agglomerate rapidly to yield particles in the greater than 0. 1 micrometer range • Condensable Particulate Matter – Non-particulate matter that condenses and/or reacts upon cooling and dilution in ambient air to form particulate matter in the PM 2. 5 classification. within a few seconds after discharge from the stack
Sources of all Air Pollutants Measured in California Hydrocarbons (HC), Carbon Monoxide (CO), Oxides of Nitrogen (NOx), Oxides of Sulfur (SOx) and Particulate Matter (PM) ** Residential fuel combustion, farming operations, construction, road dust, wind-blown dust, fires, waste burning, utility equipment and other miscellaneous sources.
Health Conditions Associated with Air Pollution Exposure Disease/Condition Role of Air Pollution Associated Factors Acute Bronchitis SO 2, soot, petrochem. irritative effects Cigarette smoking may be synergistic Acute Respiratory Infections Increased risk in young children Poverty, malnutrition, pathogen exposure Asthma Aggravated by respiratory irritation Pre-existing respiratory allergy; airway hyperactivity Chronic bronchitis Cough/sputum aggravation Cigarette smoking; occup. Death Fine particulates incr. heart and lung disease Pre-existing heart and lung disease Eye irritation Photochemical oxidants, aldehydes, peroxyacetyl nitrates and PM Differing susceptibilities Headache Carbon monoxide incr. carboxyhemoglobin Smoking also increases carboxyhemoglobin; indirect effect Lead toxicity Contributes to body Lead exposure sources at
• • • Common Health Effects of Ambient Air Pollution Respiratory symptoms most common Cough, nose and throat irritation & mild shortness of breath. Often associated with eye irritation and a sense of fatigue Exacerbation of allergic symptoms is typical Worsening of symptoms of asthmatics and those with chronic pulmonary disorder – Evidence of association between asthma attacks and atmospheric level of oxidants and sulfate More frequent respiratory tract infections in areas with higher air pollution levels Cardiovasculat effects from atmospheric CO – Reduces oxygen delivery to myocardium and may aggravate atherosclerosis Air pollution respiratory effects increase strain on heart in people with chronic bronchitis Mucosal irritation, nasal tickle, conjunctivitis Eye irritation, esp. from particulates and photochemical oxidants
Air Pollution and Cancer Risks • Documented for community air pollution from point sources, such as smelters releasing arsenic (lung cancer) • Radon air pollution of indoor air (lung cancer) • Work place exposure to asbestos and mesothelioma of the lung • Central nervous system toxicity as learning disabilities in children from airborne lead
WHO Air Quality Guidelines • WHO has air quality guidelines – Represent widely agreed, contemporary assessments of health effects of air pollution – Recommended targets for air quality at which the health risks are significantly reduced. • Recommend reducing particulate matter (PM 10) pollution from 70 to 20 micrograms per cubic metre – Can reduce air quality related deaths by ca. 15%. • Will help countries reduce the global burden of disease from respiratory infections, heart disease, and lung cancer.
WHO Guidelines - Air Quality and Health • It is possible to derive quantitative relationships between air pollution levels and specific health outcomes (increased mortality or morbidity). • Allows invaluable insights into the health improvements that could be expected if air pollution is reduced. • Even relatively low concentrations of air pollutants have been related to a range of adverse health effects. • Poor indoor air quality may pose a risk to the health of over half of the world’s population. • In homes where biomass fuels and coal are used for cooking and heating, PM levels may be 10– 50 times higher than the guideline values.
PM Guideline Values PM 2. 5 PM 10 10 μg/m 3 annual mean 25 μg/m 3 24 -hour mean 20 μg/m 3 annual mean 50 μg/m 3 24 -hour mean • Aim: achieve the lowest concentrations possible • No threshold has been identified below which no health effect is observed • Recommended value should represent an acceptable and achievable objective to minimize health effects in the context of local constraints, capabilities and public health priorities. • PM affects more people than any other pollutant. • Major components of PM are sulfate, nitrates, ammonia, sodium chloride, carbon, mineral dust and water. • Complex mixture of solid & liquid particles of organic & inorganic material. • PM 2. 5 (aerodynamic diameter smaller than 2. 5 µm consodered more dangerous – When inhaled, they may reach the peripheral regions of the bronchioles, and interfere with gas exchange inside the lungs.
PM and Health Effects • Health health occur at exposure levels now experienced by most urban and rural populations in both developed and developing countries. • Chronic exposure contributes to risks of developing cardiovascular and respiratory diseases, as well as lung cancer. • In developing countries: – Exposure from indoor combustion of solid fuels on open fires or traditional stoves increases the risk of acute lower respiratory infections and associated mortality among young children; – Indoor air pollution from solid fuel use is also a major risk factor for chronic obstructive pulmonary disease and lung cancer among adults. • Mortality in cities with high levels of pollution exceeds that observed in relatively cleaner cities by 15– 20%. • In the EU, average life expectancy is 8. 6 months lower due to exposure to PM 2. 5 produced by human activities.
PM and WHO Health Effects Guidance • Reducing particulate matter pollution from 70 to 20 micrograms per cubic metre as set out in the revised (2005) Guidelines, is estimated to reduce air quality related deaths by around 15% • Reducing air pollution levels helps reduce the global burden of disease from: – respiratory infections – heart disease – lung cancer. • Reducing the direct impact of air pollution will also reduce emissions of gases which contribute to climate change and provide other health and environmental benefits.
Ozone WHO Guidance • Guideline value: 100 μg/m 3 8 -hour mean • Definition and Principal Sources: • Ozone at ground level – not to be confused with the ozone layer in the upper atmosphere – is a major constituents of photochemical smog. • Formed by reaction of sunlight (photochemical reaction) with of pollutants such as: – Nitrogen oxides (NOx) from vehicle and industry emissions – Volatile organic compounds (VOCs) emitted by vehicles, solvents and industry. • Highest levels occur during sunny weather.
Ozone Health Effects • Excessive levels cause breathing problems, trigger asthma, reduce lung function and cause lung diseases. • In Europe: currently one of the air pollutants of most concern. • Studies report daily increases of: – 0. 3% for mortality and – 0. 4 % for heat disease • per 10 µg/m 3 increase in ozone exposure
NO 2 40 μg/m 3 annual mean 200 μg/m 3 1 -hour mean • At short-term levels >200 μg/m 3: a toxic gas causing significant inflammation of the airways. • The main source of nitrate aerosols, which form an important fraction of PM 2. 5 • In the presence of ultraviolet light forms ozone. • The major anthropogenic emission sources are combustion processes: – Heating – Power generation – Engines in vehicles and ships
NO 2 Health Effects • Epidemiological studies: – Increased symptoms of bronchitis in asthmatic children associated with long-term exposure to NO 2. – Reduced lung function development linked to NO 2 at concentrations currently measured (or observed) in cities of Europe and North America.
SO 2 20 μg/m 3 24 -hour mean 500 μg/m 3 10 -minute mean • Health effects associated with lower levels than previously believed. – Need for greater protection led to revised guideline values in 2002. • Causality of health effects still uncertain, but reducing concentrations is likely to decrease exposure to copollutants • Definition and principal sources: – A colourless gas with a sharp odour. – Produced from burning fossil fuels (coal and oil) and the smelting of mineral ores that contain sulfur. – Main anthropogenic source is the burning of sulfurcontaining fossil fuels for domestic heating, power
SO 2 Health Effects • Affects the respiratory system and the functions of the lungs • causes irritation of the eyes. • Inflammation of the respiratory tract causes: – – – Coughing mucus secretion aggravation of asthma chronic bronchitis Increased susceptibility to infections of the respiratory tract. • Increased hospital admissions for cardiac disease and mortality increase on days with higher SO 2 levels. • When SO 2 combines with water, it forms sulfuric acid – The main component of acid rain which is a cause of deforestation.
Smoke in the Kitchen Health Impacts of Indoor Air Pollution in Developing Countries UN Commission on Sustainable Development, 14 th Session Partnerships Fair, 2 May 2006 Eva Rehfuess Programme on Indoor Air Pollution World Health Organization
Prabir Mallik/The World Bank
What is the problem? • Some 3 billion people rely on solid fuels (e. g. dung, wood, agricultural residues, charcoal, coal) for their basic energy needs. • Cooking and heating with solid fuels leads to high levels of indoor smoke, a complex mix of health-damaging pollutants (including small particles, carbon monoxide, nitrogen oxides). • Typical small particle levels (PM 10) in biomass fuel-using home: 1000+ µg/m 3 European Union standard: 50 µg/m 3 Nigel Bruce/ITDG
Who is most at risk? WHO, Fuel for Life: Household Energy and Health
What are the health impacts? Health outcome • ALRI (children <5 yr) • COPD (adults) • Lung cancer (coal) Evidence Between 10 - 20 studies Few measured exposure Confounding problematic • • Several consistent studies (more conflicting for asthma) Tuberculosis Cataract Upper airway cancer Asthma Low birth weight Perinatal mortality Otitis media Cardiovascular disease Very few studies, support from environmental tobacco smoke and ambient air pollution studies No studies, but suggestive Smith, Mehta and Feuz, 2004
Who is most affected? Highly Neglected Issue! 1. 5 million annual deaths • in the poorest countries • > 800 000 among children • > 500 000 among women
What is the link between indoor smoke and the Millennium Development Goals? "We will spare no effort to free our fellow men, women and children from the abject and dehumanizing conditions of extreme poverty, to which more than a billion of them are currently subjected. " United Nations Millennium Development Declaration, signed by all 191 Member States of the United Nations in September 2000 MDG 1: Eradicate extreme poverty and hunger MDG 3: Promote gender equality and empower women Household Energy MDG 4: Reduce child mortality MDG 7: Ensure environmental sustainability
What does the World Health Organization do? • Documenting the health burden of indoor air pollution and household energy e. g. assessment of the burden of disease • Evaluating the effectiveness of technical solutions and their implementation e. g. catalogue of methods; regional training workshops • Monitoring changes in household energy habits over time e. g. MDG indicator on solid fuel use • Acting as the global advocate for health as a central component of international/national energy policies e. g. cost-benefit analysis of household energy interventions; Ministerial side-event on household energy and health
4000 deaths a day from cooking fires? Let's prevent them! CSD-14, New York, Conference Room 2 11 May 2006, 6: 15 pm – 7: 45 pm
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