Several areas will require attention
Significant Atmospheric Sources
Atmospheric sources which have been noted to be contributing to air quality limit exceedances and which are associated with increasing emissions include:
- road vehicle exhaust emissions,
- coal-fired power stations,
- airport releases (specifically international airports) and
- poorly controlled industrial operations.
The growth of road transportation and power generation emissions have been noted to be significance in terms of increasing South Africa’s contribution to global warming.
Atmospheric sources receiving increasing attention due either to uncertainties or concerns regarding the extent and nature of their emissions and the potential for local impacts due to such emissions include:
Emerging Priority Pollutants
- filling stations,
- landfill gas emissions,
- spontaneous combustion emissions from coal discard dumps and open cast mines,
- waste water treatment works,
- from tyre burning, and fugitive releases related to commercial agriculture including crop and lifestock farming.
Pollutants which are important due to their resulting in widespread exposures and risks are: inhalable particulates (PM10), nitrogen dioxide, ozone, and benzene. PM10 concentrations have been shown to be elevated across the country with significant exceedances of human health limits. Increasing emphasis is being placed on PM10 due to the issuing of linear dose-response curves for this pollutant by health organisations such as the World Health Organisation and the implementation of very strict limits for this pollutant by European and Austrolasian countries.
Although nitrogen dioxide air quality limit exceedances are currently mainly restricted to high density traffic-related sites and exceedances of limits for short-term averaging periods, the spatial extent and frequency of exceedance is anticipated to be increasing due to increased rates of vehicle activity. Ozone concentrations have been found to exceed health limits at most sites at which this pollutant is measured. Benzene is of concern due to it being a carcinogen and being related to vehicle exhaust emissions which are currently increasing.
Other pollutants which are likely to require increased attention in the future include: persistent organic pollutants such as dioxins and furans, finer particulate fractions, e.g. PM2.5, particulate concentrations < 2.5 μm diameter, and indoor air pollutants which are unrelated to fuel burning for cooking and space heating (e.g. formaldehyde and radon).
Requirements for Effective Air Quality Management under the Air Quality Act
Effective air quality management under the impending Air Quality Act will be dependent on the following conditions being met:
Timeous development and adoption of regulations under the Act, e.g. ambient air quality
standards, emission limits, guidelines for air quality monitoring, modelling and management.
Capacity building of local, provincial and national government personnel in terms of provision of adequate training, support and resources.
Development and effective implementation of coherent air quality management systems
comprising current and comprehensive emissions inventories, cost-effective and well run
monitoring networks, suitable air dispersion models.
Standardisation of monitoring methods, emissions inventories, modelling approaches and
source, emissions, air quality and meteorological data reporting.