Indoor Air Quality – IAQ Standards in South Africa
The growing danger of high levels of atmospheric pollution due to toxic emissions, such as nitrogen oxides and carbon monoxide from internal combustion engines, are common knowledge and a cause for worldwide concern. By contrast, the purity of the air we breathe in our homes or whilst we are at work often tends to draw less attention. Nevertheless, in keeping with best industrial hygiene practices, the World Health Organisation considered it necessary to define acceptable standards for managing indoor air quality (IAQ) in the workplace.
The WHO recommendations address ambient levels of suspended particles and gases that pose no significant threat to an exposed worker. In addition, authorities in many countries, including South Africa, have introduced local standards. In each case, the objective is to achieve limits of common air pollutants consistent with the long-term health of all exposed workers, including those deemed most vulnerable.
In South Africa, an act governing national environmental management defines the local standards for indoor air quality. First published in the 1990s, the original Act has undergone several revisions. The South African Bureau of Standards determined the most recent figures. The SABS document defines the limits for particles with a diameter less than 10µm, sulphur dioxide, nitrogen dioxide, carbon monoxide, ozone, lead, and benzene. It may help to understand the importance of these limits to review some of the possible consequences of exceeding them.
Suspended Particulate Matter
Most people are aware of the life-threatening effects of inhaling asbestos fibres or coaldust and how managing indoor air quality has helped limit the incidence of fatal respiratory disorders. Nevertheless, many other suspended particles can pose a health threat as hay fever sufferers will be well aware. Although their effects depend on size, chemical composition, concentration, and frequency of exposure, the smallest particles pose the greatest risk. The hairs will trap the larger ones in the nasal passages. However, those less than 10µm in diameter can penetrate deep into the lungs, causing cell damage and, with repeated exposures, eventually impairing respiratory function.
Strategically positioned dust extractors will help maintain indoor air quality by removing most of the offending suspended solids, while masks offer a means to protect exposed workers from any residual particles.
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Lead and Similar Toxins
The metal is highly toxic to humans, resulting in numerous pathologies ranging from brain and kidney damage to gastrointestinal disorders. Arsenic, cadmium, and nickel are all known carcinogens whose atmospheric levels must be strictly controlled. Respirators and protective clothing are often the only means to keep workers safe from the potentially lethal effects of inhalation or skin contact when any of these elements may threaten the indoor air quality.
Gases and Organic Solvents
These may be the by-products or the end products of an industrial process, and all are potentially dangerous if inhaled for sustained periods. Some cause damage to lung tissue, while others interfere with the ability to absorb oxygen. Benzene is one of several organic compounds identified as carcinogenic.
Help is on Hand
The first step in ensuring worker safety will be to perform assays to determine the levels of any particles or chemicals that may threaten indoor air quality. IOH Solutions is a well-established and accredited industrial hygiene specialist offering professional services to improve workplace health and safety in Gauteng and the Eastern and Western Cape.