Author: Hanlie Liebenberg Enslin on behalf of National Association for Clean Air (NACA )Public awareness around air pollution has increased dramatically over the past decade. For many years, air quality management remained on the back burner of environmental policies, mainly because air pollution is not always visible and not restricted by geographical boundaries. In most instances it is not easy to trace the source of pollution, and especially so for air pollution.
Air pollution is a product of both natural and manmade activities. The latter derives from industrial operations, transportation, household fuel burning, waste treatment, mining and agriculture. Natural sources of air pollution include wild fires (although sometimes started by humans), wind-blown dust, sea spray, pollen and ash (and other pollutants) from volcanic eruptions. Once emitted into the air, pollutants are transported and dispersed over space and time, directed by wind speed and wind direction. Other weather conditions also influence the way pollution is dispersed and removed from the air. Temperature influences the rise of pollution plumes whereas rainfall will wash the pollution out. All these factors play a part in transporting and diluting pollutants. Our main concern with air pollution is the amount of pollution that eventually reaches ground level, where it is then inhaled by humans.
Various respiratory and other health problems are associated with the inhalation of polluted air. These pollutants comprise various compounds such as sulphur dioxide, oxides of nitrogen, carbon monoxide, benzene, ozone and dust. These criteria pollutants are the cause of most of the air pollution-generating activities and have resulted in a great deal of researched concerned with the impacts on human health and the environment. Ambient air quality guidelines and standards are based on the scientifically researched levels of impact of these pollutants, and are used by various organizations and countries as indicators for health and environmental impacts. In South Africa,
National Ambient Air Quality Standards were published in December 2009, providing legally enforceable ambient air pollution limits for all criteria pollutants.
The South African challenge Most man-made air pollution can be fairly easily managed. Industries, for example, are controlled through the National Environmental Management: Air Quality Act (Act No. 39) of 2004 under a section referred to as Listed Activities and Minimum Emission Standards. A Listed Activity triggers the requirement for an Atmospheric Emissions License (AEL), which requires that an industry report on all its air pollution sources. An AEL is granted once the industry can prove that they can comply with the requirements as set out in the Act. Industries are therefore compelled to compile comprehensive emission inventories for the entire site where a Listed Activity is present. The District or Metropolitan Air Quality Officers are responsible for issuing AELs. Non- Listed Activities such as small boiler operations,vehicle tailpipe emissions, waste burning and pesticide spraying, to name a few, are controlled by the Metropolitan, District and Local Municipalities through the development of by-laws (a template for the development of by-laws was published by the Department of Environmental Affairs (DEA)).
Certain man-made pollutants such as household fuel burning proves more difficult to manage. For many living in informal settlements, air pollution is part of everyday life and not seen as something harmful or out of place. Smoke blankets, from household fires is a common phenomena in early mornings and late afternoons. Coal and wood are cheap and can be used not only for cooking, but also for space heating and to provide light. Over the years, coal and/ or wood fires have become synonymous with the life of the less privileged. This poses a major problem, since household fuel has been identified throughout various studies as one of the most significant sources of atmospheric emissions, impacting on human health and well-being. The most significant pollutants from coal and wood combustion include very fine particulates (PM10and PM2.5) and sulphur dioxide. With the pollution released within the immediate environment of people (i.e. room), the impact is very significant since the pollution has no time to dilute and disperse. A study done in Soweto indicated that domestic coal combustion contributed approximately 70% of the ambient total particulate matter loading ) and in the Vaal Triangle it was found to contribute on average 37% to the atmospheric particulate load, rising to 65% in winter (Engelbrecht et.al., 1998). A research project initiated by the Medical Research Council in 1990 found that double the number of children living in households with open fires experience respiratory symptoms like sneezing, couching, and runny/stuffy noses than those from homes with no open fires.
Aside from industries and household fuel-burning, there are rising concerns of pollution emission sources such as vehicle tailpipes as well as the increasing demand for energy and our country’s economic reliance on the mining sector. The combination of urbanization, ailing and badly planned infrastructure and public transport is increasing the congestion on our roads. Idling and stop-start activities result in more emissions than driving at higher speeds and this is typical of city-style driving. Vehicle exhaust emissions are estimated to be a significant urban air pollution source, contributing around 30% to the total fine particulate and sulphur dioxide emissions from fuel-burning processes. Between 1998 and 2004, petrol sales increased by 14% and diesel sales by 50%. Gauteng, for example, has the largest vehicle population in the country.
Traffic volumes on the Ben Schoeman Highway between Pretoria and Johannesburg alone, increases by roughly 7% annually with no signs of declining. Even with the Gautrain in full operation, it is expected that private vehicle ownership will increase. The City of Johannesburg and the Gauteng Province, identified vehicle emissions to be the main contributor to a number of pollutants such as nitrogen dioxide, carbon monoxide and benzene.
An increasing demand for electricity in South Africa has both direct and indirect air pollution impacts. Coal-fired power stations account for more than 90% of our energy demand. This is likely to continue over the short- to medium term even with the introduction of alternative fuels such as nuclear power, bio-fuels, solar power and wind power. The burning of coal at power stations, as with household coal burning, results in sulphur dioxide, nitrogen dioxide, carbon monoxide and particulate matter emissions. Coal mining operations are secondary impacts from coal-fired power stations. Coal mines, as with any other open pit mining, does not only impact on air pollution directly but also results in a wider range of environmental impacts. In mining operations, particulate matter is the main pollutant of concern.
A number of activities exacerbate the situation such as drilling and blasting, trucks on unpaved roads, loading and off-loading of material and storage piles. Add wind to this, and you have various particulates blown in the form of dust. The mining of precious metals such as chromium, platinum and gold also add heavy metals to the pollutant mix. Uranium and to a lesser extent gold also have radiation associated with the process.
Managing air pollution in South Africa
As a developing country, South Africa requires sustainable economic growth to ensure development. This goes hand in hand with industrialization, urban sprawl, higher energy demands and of course, air pollution. The Air Quality Act sets out to protect and enhance air quality in South Africa and to secure ecologically sustainable development through reasonable air pollution prevention measures. This can be achieved through the development of air quality management plans and by involving all spheres of government and the public sector.
The first step in air quality management is to determine the quality of air i.e. fitness for human consumption. In 2009, the Department of Environmental Affairs published the
State of Air Report 2005 for South Africa with the purpose of providing insight into the sources of emission and the associated human health, welfare, and broader environmental effects. The report sets out to indentify significant sources, pollutants and areas of impact in combination with existing air quality management practices. The goal of this Report was to pave the way for an integrated air quality management system for South Africa. The State of Air Report provides trends in ambient air concentrations based on ambient air quality data measured at more than 120 stations across the country over a period of 10 years (1994 – 2004). The key conclusion from this report was that very little is known about the status of air quality in rural and low-income residential areas. This is mainly due to the fact that industries initiated monitoring of air quality predominantly in the industrial areas. Monitoring of air pollution is still restricted to a few criteria pollutants with little information on ozone and benzene. The available data did however flag sulphur dioxide and fine particulates as the main pollutants of concern. These are primarily a result of household fuel-burning,
industrial operations, vehicles and power generation. Household fuel burning remains the most precarious issue to human health and is a national problem. This challenge is addressed by various campaigns that introduce different fire lighting methods, providing interim measures for the short term. Longer term strategies include the supply of electricity to poor households, improved housing designs and the utilization of solar power.
Regarding the important transport sector; a number of policies over the past 10 years have already ensured significant reductions in air pollution despite the ever increasing traffic volumes on our roads. The changing fuel specifications in the past several years started with the phasing out of leaded petrol in the 2006. Conversely this also resulted in an increasing concentration of benzene in lead-free petrol. Sulphur content in diesel was reduced to 500ppm, with a niche grade of 50ppm being introduced from 2006. Improvements in the fuel efficiency of vehicles, the incorporation of emission controls in new vehicles, and additional changes in fuel composition will be responsible for realising emission reductions. The biggest concern however remains the steady increase of ageing vehicles on our roads that emit higher levels of pollution than newer models. Managing these various sources of pollution, understanding the significance of their contributions and finding practical means to reduce the pollution from these sources is a daunting task. The Air Quality Act has however set out a tool to manage pollution at various spheres of government. Air quality management plans provide not only the platform, but the tools for successfully integrating and implementing these variables into a coherent workable solution.
Dust is the generic term for fine particulates that are airborne. These are usually smaller than 1mm and the very fine fraction, smaller than 10 microns (called PM10) and smaller than 2.5 microns (called PM2.5), can be trapped in the lung membrane, causing health problems. The coarser fraction (between 10 microns and 1mm) cannot be inhaled but is the fraction that is visible and causing nuisance impacts.