HEALTH damaging particles in polluting gases emitted by industry, traffic and domestic heating have a ‘cooling’ effect on the climate. In reducing local air pollution we are lowering this cooling effect and inadvertently accelerating global warming. Is clean air bad for the planet?
The burning of fossil fuels such as coal and oil emit gases with small particles known as aerosols. These aerosols include PM10 and sulphates and are found in motor vehicle emissions as well as industrial and domestic heat emissions. They have been linked to asthma, heart problems, lung cancer and premature death as well as having an impact on ecosystems. Aerosols influence the nature of clouds and play a key role in reflecting incoming solar radiation and reducing temperatures at the earth’s surface. They mask the earth from the effects of global warming. While there is still scientific uncertainty about the contribution of this group of air pollutants to ‘climate cooling’ there is an urgent need to reduce the concentrations of these small particles to protect human health and environment.
The World Health Organization (WHO) estimates that outdoor air pollution is responsible for 600,000 premature deaths worldwide each year. Britain is one of ten European Union member states that have recently been warned over excessive levels of PM10. The UK together with Cyprus, Estonia, Germany, Italy, Poland, Portugal, Slovenia, Spain and Sweden could face court action if it fails to meet a European directive limiting these harmful airborne particles. In particular, developing cities in Asia and Africa are struggling with a rapid growth in traffic, urban expansion and industrial development. This has resulted in high levels of polluting air emissions and poor air quality.
In many large Asian cities you will find street hawkers sitting beside strategic road junctions experiencing the general hustle and bustle of daily life. However these individuals are being exposed to high concentrations of motor vehicle pollutants increasing the risk of developing respiratory disease and cancer. Children ill with respiratory disease caused by exposure to high concentrations of air pollutants will be children that will not learn very well, will suffer in adult life from low levels of qualifications and skills which in turn has implications for their quality of life and the economic development of the country as a whole.
The issue of local environmental quality versus global environmental pollution poses an interesting ethical dilemma. Policies to reduce local air pollution such as improving vehicle technology, installing clean technologies in polluting industrial plants and introducing low-sulphur fuels will protect the health of many urban residents. However, by reducing aerosols emissions we are reducing their climate cooling effect. This could speed up global warming and climate change and thus threatens the lives of 7 billion people on the planet.
If we are to avoid the inadvertent warming resulting from a reduction in PM10 and sulphate aerosols then we need to reduce ‘short-lived’ climate warming gases. That is the view of the Global Atmospheric Pollution Forum – an international partnership of governmental and non-governmental organisations that address air pollution. Unlike carbon dioxide, a key greenhouse gas that remains in the atmosphere for up to 100 hundred years, black carbon, ground-level ozone and methane are substances that have a relatively short-life in the atmosphere, lasting from days to weeks in the case of ozone and black carbon and for a decade with regard to methane. Black carbon is emitted from diesel engines, while ground-level ozone is produced from the reaction of gases from vehicle exhaust, industrial emissions, and chemical solvents. These pollutants are both local air pollutants as well as climate warming gases. While methane is an ingredient needed for the formation of ground-level ozone. Therefore decreasing the concentrations of these gases by cutting emissions could produce relatively quick climate results. This would counteract the cooling effect caused by a reduction in other pollutants such as PM10 and sulphates needed to protect human health. Measures to reduce concentrations of ground-level ozone, black carbon and methane must be pursued alongside cuts in carbon dioxide emissions. This approach should to be addressed in future climate change negotiations. A global assessment of short-lived pollutants is required to feed into the policy process.
It is clear air pollution and climate change are intimately linked with regard to sources and effects on human health and environment. Actions taken to reduce emissions of traditional pollutants may increase or decrease emissions of greenhouse gases. Likewise, strategies to reduce greenhouse gases can have positive or negative effects on air pollution. If we are to develop effective air pollution prevention policies then we to need an integrated approach to address both local air pollution and climate change. This means abandoning the traditional view of the environment as being made up of separate parts and treating it as a functioning interrelated system.
By taking a holistic view of air pollution and climate change we can ensure that clean air will never be bad for the planet.
© Gary Haq 2009