Air Quality Monitoring

What is PM10?

PM₁₀ refers to particulate matter (dust) that is smaller than 10 microns in diameter. These fine particles are not visible to the naked eye.

PM₁₀ levels are measured in micrograms per cubic metre of air (µg/m³).

Higher numbers indicate more dust in the air.

How Air Quality is Monitored

Mid West Ports operates a network of real‑time PM₁₀ monitoring stations located around the Port boundary, including:

• Port Way
• Connell Road
• Lemmon Road
• Berth 1

These stations continuously measure dust levels and send data to Mid West Ports servers for display on this portal.

A background monitoring station is also located outside the Port area in the suburb of Bluff Point (Kempton St).

Data shown on the portal is unvalidated real‑time data, meaning it may occasionally include interruptions or instrument errors. Final validated results are reported formally under Mid West Ports’ regulatory obligations to the Department of Water and Environmental Regulation (DWER). These reports are published on our website and can be viewed here: Air Quality Monitoring Reports

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1 hour Average Dust Levels

The portal displays 1‑hour average PM₁₀ concentrations, updated every clock hour.

Each value represents the average dust concentration measured over the previous hour.

Results align with DWER air quality reporting framework used across Western Australia.

Short‑term increases in PM₁₀ can occur due to a range of factors, including weather conditions, regional activities, or local sources - not only port operations.

What is the Air Quality Index (AQI)?

MWPA applies the DWER Air Quality Index (AQI) to categorise dust levels.

The AQI converts measured PM₁₀ concentrations into a simple number and colour category, helping to quickly understand current air quality conditions.

The AQI is based on the National Environment Protection Measure (NEPM) for ambient air quality, with the national PM₁₀ standard being 50 µg/m³ averaged over a 24 hour period.

AQI Categories

This portal uses the DWER five‑category colour system for PM₁₀:

When PM10 concentrations are recorded as Poor or above, Mid West Ports investigates the cause and takes action where emissions are confirmed to be Port‑related.

Understanding Wind Conditions

Wind plays an important role in how dust moves through the environment.

The portal displays:

• Wind direction – shown as the direction the wind is coming from (for example, a south‑east wind blows from the south‑east)
• Wind speed – described using the Beaufort Wind Scale, ranging from calm conditions to very strong winds

Wind information helps explain:

• Why dust levels may rise or fall
• Whether dust is likely moving toward or away from the Port
• Whether dust may be coming from sources outside the Port area.

Why Dust Levels Aren't Always Caused by the Port

Not all dust recorded by the monitoring stations comes from Port activities.

The monitors measure all PM₁₀ in the air, including dust from external and regional sources that Mid West Ports does not control.

These sources can include:

• Wind‑blown sand from beaches and coastal areas
• Dust from surrounding land and natural terrain
• Sea salt particles, which are common in coastal environments
• Regional weather events, such as hot, dry and windy conditions
• Activities occurring outside the Port, such as transport, construction, or agriculture

During these conditions, several monitoring stations - including the background monitor - may record high values at the same time. This usually indicates a regional source of dust.

How Mid West Ports Determines Whether Dust Is Port-Related

When elevated dust levels occur, Mid West Ports investigates all available data to understand the source of the dust, and considers:

• Wind direction and wind speed
• Which monitoring stations are affected and when
• Whether monitors upwind of the Port are also elevated
• Readings at the background monitoring station
• Visual observations of dust
• Whether dust levels change when Port activities are paused