Description
The atmosphere is a shared resource. The quality of air depends
on the quantities of natural and human-induced (anthropogenic)
emissions to the atmosphere, as well as on the potential for dispersing and removing pollutants from the atmosphere. Air pollutants vary according to the impact that they have as well as the length of time they remain in the atmosphere.
Gases such as methane, nitrous oxide, and chlorofluorocarbons
are long-lived and internationally significant because of their
implications for global warming and stratospheric ozone depletion.
The problem posed by carbon dioxide (CO2) is that anthropogenic
generation is faster than environmental re-utilization, and leads to
a rise in atmospheric concentration, with consequent impact on
global warming. Pollutants such as nitrogen dioxide (NO2), sulphur
dioxide (SO2), carbon monoxide (CO), and particulate matter (PM)
are significant, primarily in terms of local human health impacts.
These gases also have local and regional ecological impacts.
The purpose of State of Air for South Africa, 2005 is to give an
overview of the state of air quality in South Africa, providing insight
into the sources of emissions, and their associated health, welfare,
and broader environmental effects. The identification of significant
sources, pollutants, and impact areas is an important first step towards air quality management. The report also summarizes current air quality management practices, and explores opportunities for reducing emissions and improving the quality of the air. Although it focuses mainly on criteria (common) pollutants as per national framework and local and urban ambient air pollution issues, the report also refers to non-criteria pollutants, regional and global challenges, and health risks posed by exposure to indoor air pollution.
In characterizing the national state of air quality, reference is
made to available information from source inventories, ambient air
quality monitoring stations, and relevant literature. Air quality
monitoring data for over 120 stations across the country were
obtained for the purpose of informing State of Air for South Africa,
2005. All available data for the period 1994–2004 were
collected.
In the supplementary report entitled Technical Compilation to
Inform the State of Air Report (DEAT, 2006a), a detailed description
of the entire dataset is given, and the quality of the data evaluated.
Summary statistics are presented for all the data collected. This
technical support document covers air quality monitoring activities
and presents trends at all stations at which adequate data were collected. Air quality trends for selected air pollution monitoring stations were extracted for inclusion in the State of Air Report 2005 to illustrate the state of air in local environments, for example in heavy industrial areas, dense low income settlements, and areas
where the roads carry high volumes of traffic.
