Source: The Conversation (Au and NZ)
A breath of fresh air does wonders for the body and mind.
In some areas, however, the air may not be as clean as it seems. This may be due to pollution or natural hazards such as bushfires and dust storms.
If you’re worried about air quality in your local area, there’s no shortage of apps and websites promising to help.
But which should you choose? And can you trust the information they offer?
Where to start
In Australia, the most reliable place to start is your state or territory Environmental Protection Authority website.
These sites publish air quality information in many formats, from technical data and colour coded advisory maps to emergency incident updates.
The data comes from government monitoring networks, which operate under the Australian National Environment Protection (Ambient Air Quality) Measure. This framework sets assessment standards to ensure air quality data is collected and interpreted in a consistent, accurate and transparent way.
At first glance, this data may look intimidating. The simplest way to interpret it is to check the air quality category for your location. These categories are colour coded based on a traffic light system, with green indicating “good” air quality and dark red identifying areas with “extremely poor” air quality.
To determine these categories, the government collects data on the pollutant concentration in an area, which is the amount of a harmful substance found in a volume of air. This data is quality checked and published as hourly updates.
What about phone apps?
Mobile phone apps provide air quality information on the go. These apps often re-purpose data from government websites, sometimes in combination with low-cost monitoring networks like IQAir and PurpleAir.
These networks typically use indicative data, which points to general trends without offering exact values. So while these apps are convenient, it pays to check where their data comes from and if it has been modified in any way.
Many mobile apps use a traffic light reporting system that looks similar to the government’s air quality categories. However, a handful use the Air Quality Index. This index ranks common pollutants – such as carbon monoxide and sulfur dioxide – on a scale from 0 to 500. The higher the number, the most “risky” the pollutant from an air pollution and human health perspective.
This numbers-based approach is useful for classifying air quality, but can hide important details. For instance, an app may not indicate which pollutant the air quality index is based on or whether measurements are taken hourly, daily or weekly. Just as weather apps can give varied forecasts, air quality apps can report different values for the same place and time because they use different models and data sources.
Grassroots solutions
To gather accurate air quality data, government monitoring systems rely on equipment known as reference instruments. These are highly precise devices that require regular maintenance, along with frequent checks and adjustments to ensure accurate readings. Given their complex design, reference instruments can be difficult to move and expensive to operate.
In contrast, indicative monitors are small, compact and affordable devices powered by batteries or solar. They estimate levels of dust, temperature and humidity. Some also measure gases and volatile organic compounds, which have been shown to harm human health.
Indicative monitors help fill gaps in official monitoring data and are widely used in community projects, such as OPENAIR and Air Watch. On a broader level, indicative networks can help identify and track pollution sources such as vehicle emissions and woodsmoke.
However, their data must be interpreted with caution. Without regular care and maintenance, the sensors in indicative monitors can become less accurate over time. What’s more, monitors can be placed in unsuitable locations – for instance, next to barbecues or outdoor smoking areas – where poor airflow can distort the readings.
So while indicative monitors can alert us to poor air quality, the data they provide is approximate, not exact.
What you can do
Air quality data from apps and websites can vary in quality and reliability.
Before trusting an air quality data app or website, it’s best to ask four simple questions:
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Who runs it? This may be a government agency, university, research body, company or community network.
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What data is it showing? Certain sources may present primary data collected by the organisation that operates the app or website, while others rely on secondary data repurposed from somewhere else.
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What instruments do they use? This determines whether an app or website provides estimates, indicative data or reference grade data, which is the gold standard.
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What quality control is in place? This includes measures such as regular maintenance and calibration, being placed in an appropriate location and transparent information about a system’s limitations.
If a platform cannot provide clear answers to these questions, it may still be useful. But it should not be treated as the final word on air quality.
So the challenge is not finding data, but knowing how to assess its quality and interpret it responsibly.
Margaret Davidson is affiliated with the Australian Institute of Occupational Hygieniests, the Australasian College of Toxicology and Risk Assessment, the Thoracic Society of Australia and New Zealand and ASTM International.
Original source: https://analysis1.mil-osi.com/2026/11/01/worried-youre-breathing-unclean-air-heres-how-to-measure-it/