How does Indoor Air Quality (IAQ) impact fit-for-purpose environments – part two

Indoor air quality at work

Welcome to part two of our four-part series on the impact that poor Indoor Air Quality has on occupant wellbeing. This time we look at the current IAQ standards for New Zealand workplaces and the conversations we should be having if we are to effect change.

If you missed part- one, The Impact of Poor IAQ on Wellbeing, we highly recommend you read that first.


The current standards for workplace Indoor Air Quality (IAQ)

Current applicable standards for New Zealand workplaces (as for most placed around the world) prescribe minimum rates of outside air ventilation to provide acceptable levels of indoor air quality. The underlying assumption is that by delivering the prescribed rate of outside air into a building, based on full occupancy, everything will be fine. But this is rarely verified in the real world and does not consider variability of use.

Occupancy levels can impact on both building operational costs and IAQ. When occupancy is low, buildings will typically be over-ventilated – good for occupants’ health but adding unnecessarily to the building running costs. When occupancy rates are high, buildings may be under-ventilated, reducing the IAQ below required standards and effectively lowering the overall productivity levels of the occupants. The traditional ‘set and hope’ approach to air quality simply ends up being costly and counterproductive.

A better approach, but by no means perfect, is Demand Controlled Ventilation. This is where CO2 levels are measured in one or more locations throughout the building and outdoor air ventilation rates are increased or reduced to maintain CO2 levels under an acceptable level. As it is difficult and expensive to measure oxygen levels directly, CO2 is used as a surrogate measure for a corresponding reduction in oxygen levels, which is what our bodies are really reacting to.

However, the trick is to get the oxygen rich outdoor air to the right places — typically meeting rooms, breakout rooms or function spaces have disproportionately higher occupancy rates compared to standard office spaces, so this is where we see the most significant impact of low oxygen levels – depicted by reporting high CO2 levels.

An interesting phenomenon is the apparent ability of the body to rapidly adjust or readily accept poor indoor air quality. Have you ever walked into a crowded meeting room or function that has been running for some time and have been taken aback by the stale smell within the room? While the lack of ventilation is patently obvious to someone moving from a fresh environment into a stale environment, it is much less obvious to those within the room. This means that IAQ has a somewhat stealth characteristic, sneaking up on people over time. This is a fundamental reason why we need sensors and controls to continuously monitor and adjust systems to maintain acceptable indoor air quality.

The new conversation we need

As our understanding of IAQ issues increases, and the impact it has on occupant wellbeing and building lifecycle costs becomes more apparent, we need to shift the conversation on from minimum standards and instead aim for something better. Great IAQ should be the new benchmark.

That prompts more questions. What does ‘great’ look like, and how can we know it has been achieved? How do we reassure building occupants that their environment is as safe and healthy as possible? Through measurement, adjustment, and demonstration.


More in this series:
Part one – The Impact of Poor IAQ on Wellbeing,
Part three – IAQ, measuring what matters
Part four – Opposing forces of energy and health

A white paper on the entire four-part series can be downloaded here.