Most South Africans have never heard of Nipah virus, which appears on the World Health Organization’s (WHO) list of emerging infectious threats. Nipah outbreaks, including the current one in India, are rare, but the disease has severe consequences, with reported fatality rates of 40-75%. There’s no proven antiviral treatment and no widely available vaccine.
WHO says Nipah is primarily spread through close contact with infected animals or people, and is not airborne. Early in the Covid-19 pandemic, similar assurances were made about SARS-CoV-2. That misjudgement proved extremely costly.
Fruit bats of the Pteropodidae family are the natural host of Nipah virus. Image: brydyak/Freepik
An episode early in the pandemic (March 2020) added to the growing evidence that Covid-19 was transmitted through the airborne route. At an indoor choir rehearsal in Skagit Valley, Washington one person was unknowingly infectious with Covid-19. Out of 61 rehearsal participants, 53 were infected, three were hospitalised and two died. Poor ventilation at the venue was a dominant factor in spreading the infection from a single individual to so many others.
Multiple other strands of scientific evidence have changed how we think about airborne infectious risk and indoor environments. That transition is now reflected in guidance and regulations for public spaces.
Indoor air quality is a legal duty
Reflecting this international shift, the South African Physical Agents Regulations, 2024, issued under the Occupational Health and Safety Act, place IAQ solidly in the realm of workplace health and safety.
The regulations define IAQ as “the totality of attributes of indoor air at the workplace that affect a person’s health and well-being”. Growing evidence links IAQ to physical wellbeing, cognitive performance and productivity.
Regulation 12 requires employers and those who control workplaces to assess, control, monitor and document indoor air conditions.
If IAQ is now a legal obligation, it’s worth clarifying what ventilation actually means. In everyday language, ventilation is “air movement”, but in health and safety terms it has a more specific meaning: clean air delivered to occupants.
Clean air means sufficient outdoor “fresh” air, air that is filtered of contaminants or cleaned using technologies such as ultraviolet light.
The practical question is whether enough clean air reaches the breathing zone – the air people actually inhale – in an indoor occupied space.
The regulatory requirements
The SA regulations follow standard occupational-health control logic:
- Eliminate risk where reasonably practicable
- Control risk where elimination is not possible
- Use ventilation, natural or mechanical, as a primary control
Where mechanical ventilation is used, systems must comply with recognised standards (including SANS 10400), be tested by a competent person, and be maintained and re-tested at defined intervals (not exceeding 24 months) .
Regulation 12(4) specifies what must be monitored, including:
- Thermal environment (temperature, air velocity, humidity)
- Airborne contaminants such as carbon monoxide and carbon dioxide
- Occupancy levels, relative to ventilation capacity
Carbon dioxide is a proxy for ventilation adequacy – a practical indicator of whether a space is being over-occupied or under-ventilated.
International guidance defines sustained indoor CO₂ levels below about 800 ppm (or 400 ppm above outdoor air) as a sign of adequate ventilation, while recognising that CO₂ is a proxy rather than a direct measure of infection risk.
The regulations don’t require hospital-level air changes or major retrofits. They do expect proportionate, layered controls such as opening windows and improving airflow, with filtration and monitoring where justified by risk.
Portable NDIR sensors measure carbon dioxide (parts per million), temperature and relative humidity
Why IAQ is now an important business issue
From a Green Flag Association perspective, the regulations align with broader trends already affecting South African businesses and property owners and managers:
- Operational risk
Poor indoor air quality increases absenteeism, reduces cognitive performance and increases the risk of transmission of respiratory infections ranging from seasonal influenza and tuberculosis to future emerging pathogens.
- Proactive management
Covid-19 showed that scientific consensus can be delayed. By the time uncertainty resolves, businesses, health systems and economies are already paying the price.
- Monitoring and evidence
Continuous or periodic IAQ monitoring moves the discussion from opinion to evidence. It is useful for regulators, also for tenants, insurers, and boards.
- Compliance and liability
Regulation 20 makes non-compliance an offence, with fines or imprisonment possible for serious or persistent failures. Record-keeping requirements extend up to 40 years.
Looking ahead
Covid may well have been a once-in-a-century shock. Nipah virus might not spread outside current sites (India). But this is not about specific viruses or predicting the next pandemic. It’s about the fact that indoor environments drive both everyday health outcomes and business productivity. The Physical Agents Regulations require owners to address known, measurable risks in the spaces where people spend most of their waking lives.
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Additional Readings
Nipah virus
Nipah virus is a zoonotic Henipavirus transmitted from fruit bats or other animals to humans, with documented human-to-human spread.
https://www.who.int/news-room/fact-sheets/detail/nipah-virus
SA IAQ regulations
The Physical Agents Regulations, 2024 were promulgated on 6 March 2025 under the Occupational Health and Safety Act and establish indoor air quality as a physical agent subject to workplace risk management.
https://www.gov.za/sites/default/files/gcis_document/202503/52226gon5952.pdf
Great article 👍