Frequently asked questions

Air quality monitoring

Rio Tinto undertakes dust monitoring in Dampier, Karratha, King Bay,

Wickham, Point Samson and Roebourne. This document provides
answers to the most frequently asked questions relating to dust,
including a guide to some of the terms used in the context of air quality
monitoring. This document also demonstrates how to navigate the dust
monitoring website for townships near Rio Tinto's Pilbara Ports
Operations.

Rio Tinto has an air quality monitoring website http://www.pilbarairon.com/dustmonitoring/,

which allows viewers to access real time data from air quality monitors located along our Pilbara
Port Operations. The monitors report on wind speed, wind direction and particulate levels in the
atmosphere.

What are particles?

Particles or particulate matter (PM) are suspended in the air and include dust, dirt, soot, smoke, and
liquid droplets. Large particles can be seen as dust or smoke, while smaller particles are invisible to the
eye.

How are particles formed?

Some particles are natural while others are generated by human activity. Natural sources include
bushfires, dust, storms, pollens and sea spray. Those related to human activity include motor vehicle
emissions, material handling, stockpiling of material and unsealed roads.

How do particles move?

Particles become airborne when the source is disturbed. Wind, machinery movement and vehicle traffic
are common disturbances. Once airborne, dust movement is primarily influenced by wind. Wind speed
together with characteristics of the particle influences the distance particles move. Dust will travel a greater
distance with strong, fast wind. Smaller particles remain suspended in the atmosphere longer than larger
particles, which tend to settle sooner. Subsequently, larger and heavier particles tend to move shorter
distances than smaller and lighter particles. Airborne particle movement will follow the direction of the
wind.

Particles are generally removed from the atmosphere by rain or where they come into contact with
surfaces.

How do particles impact people?

Most healthy people can breathe in small amounts of particles without any long-term effects. Some people
are more sensitive, including children, adults with lung disease, asthmatics and the elderly. Higher
levels of dust can cause short-term and long-term effects, ranging from sneezing to respiratory illness.
Larger particles may get trapped in the nose, mouth or throat.

Health effects depend on a number of factors, including:

 particle size;
 the intensity and duration of the exposure;
 the chemical nature of the particles;
 the person’s health; and
 weather conditions, including wind, humidity and rainfall.

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What is measured by particulate (dust) monitoring?
Particles are classified on the basis of their size and measured in micron (µm). A µm is one
millionth of a metre, or 0.000001 metres.

Rio Tinto measures three different sizes:

 Total suspended particulate matter (TSP) is all of the suspended particulate material
present in the atmosphere, below 50 micrometers (µm) in diameter;
 PM10 is particulate matter below 10µm in diameter; and
 PM2.5 is particulate matter below 2.5µm.

For comparison, the diameter of a human hair ranges from 50µm to 100µm which is at least five
times the diameter of a PM10 particle. TEOMs and E-BAMs are used as part of the Pilbara Ports
particulate monitoring network.

Source: Queensland Government, Environmental Protection Agency

What is a TEOM?
TEOMs, or tapered element oscillating microbalance samplers, monitor the concentration of
different sized particles in the air. They can be fitted with a size-selective inlet to monitor TSP, PM10
or PM2.5. There are eight TEOMs located around Dampier, Karratha, Wickham, Point Samson and
Roebourne. These samplers draw air through a filter which is mounted on a vibrating glass tube.
Particles get trapped on the filter, which then increase the weight. This additional weight changes
how often the tube vibrates from one side to another (or oscillates).

The mass of particles is determined by the change in oscillation frequency. This mass can be
divided by the volume of air sampled by the instrument over the same period to produce the
concentration of particles within the air. As the particles can include water (via rain or humidity) as
part of their mass, it is important the inlet tube is heated to dry out the particles before they land on
the filter.

The TEOM samplers operate on a continuous basis and provide real-time data for operations and
regulatory purposes. An advantage of continuous monitoring is that it can provide additional
information, such as the time of the day that peak concentrations occurred. Such information may
be used with meteorological data to help identify the source of an emission.

Dampier North TEOM.

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What is an E-BAM?
E-BAMs, or environmental beta attenuation monitors, measure the concentration of airborne TSP.
There is one E-BAM located at the King Bay Industrial Estate. E-BAMs use the principle of beta ray
14
attenuation to measure particulate concentration levels. A small C (Carbon 14) element emits a
constant source of high-energy electrons known as beta particles. These beta particles are detected
and counted by a sensitive scintillation detector.

A vacuum pump draws a measured amount of dust-laden air through the filter tape, which is
positioned between the source and the detector thereby causing attenuation of the beta particle
signal. The degree of attenuation of the beta particle signal is used to determine the mass
concentration of particulate matter on the filter tape, and the volumetric concentration of particulate
matter in ambient air.

King Bay Industrial Estate E-BAM.

These instruments operate continuously, providing real time data for operations, regulators and the
community.

What is the difference between raw and validated data?

On this website you can see reports of validated and raw data.

Validated data
The data from each of the dust monitors is copied to an external verification consultant each day.
Data analysts review the data and identify any error readings. The validated data is used to develop
monthly overview reports which can be viewed on this website, and are also used for reporting to
regulators and community.

Raw data
Raw data reports display data that has not been through the validation process and may contain
information that is influenced by of local humidity levels, or problems with the monitoring equipment
and therefore may be incorrect. An advantage of using raw data is that it allows much more current
information to be made available on the website.

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Who maintains the monitoring equipment?
It is important that the monitoring equipment is regularly calibrated and serviced to ensure it is
providing accurate and reliable data. Maintenance is undertaken as part of a comprehensive
schedule for the dust monitors at monthly, six monthly and annual intervals. These tasks include
air flow and leak tests, cleaning of inlet tubes and calibrating the ambient temperature and wind
direction equipment. This service regime complies with the requirements of the relevant Australian
Standards for servicing of these monitoring systems, including AS2923 (1987), Ambient Air –
Guide for Measurement of Horizontal Wind for Air Quality Application, at a 90% return rate over a
calendar year.

Interpreting the data displays on the air quality monitoring website

There are several ways that data is shown on this website. Below are some key tips to help
interpret the images.

Current line graph and data summary table

For each monitoring site, different parameters can be selected and graphed over the last 30 days.
The graph shows results up until 20 minutes from the current time. The data has been averaged
over a ten minute period.

The latest particulate concentration and meteorological ten minute averages are also available as
a summary table.

Example of current line graph showing two days of PM10 ten minute averages as recorded by
the Dampier Central monitor.

Example of latest measurement summary table.

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Validated monthly graphs
These graphs show 24 hour averaged (midnight to midnight) particulate levels at the community
monitors for the latest month.

The PM10 graphs also indicate the National Environment Protection Measure (NEPM) ambient air
quality standards for PM10, while the King Bay TSP graph shows the Environmental Protection
(Kwinana Atmospheric Wastes) Policy 1992 (KEPP) reference level.

Example of validated monthly graphs

What are the air quality standards?

There are no single standards or limits for airborne dust universally applied throughout Western
Australia. Environmental criteria that are available for use are:
 Environmental Protection (Kwinana Atmospheric Wastes) Policy 1992, which has specified
levels of air pollutants (including particulates) for defined zones around Kwinana Industrial
Area; and

 National Environment Protection Measure (NEPM) ambient air quality standards for six
pollutants, including particles of PM10. There is also an advisory reporting standard for PM2.5
particles.
A table summarising the long-term environmental criteria for airborne dust applicable to Rio Tinto
Iron Ore Port Operations is outlined on the next page.

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Particle Averaging Concentration Frequency Reference
size time (µg/m3)

TSP 24 hours 150 Desirable not to be exceeded Area A (central industrial area) (a)

PM10 24 hours 50 Not more than 5 days a year NEPM for Ambient Air (b)

(a) Environmental Protection (Kwinana) (Atmospheric Wastes) Policy and Environmental Protection (Kwinana)
(Atmospheric Wastes) Regulations 1992

(b) National Environment Protection Council (NEPC), 1998, National Environment Protection Measure (NEPM) for
Ambient Air Quality, 26 June 1998 and Variation dated 23 May 2003.

More information

The Australian Government Department of the Environment:

http://www.environment.gov.au/topics/environment-protection/air-quality/air-quality-standards

The Western Australian Government Department of Environment Regulation:

http://www.der.wa.gov.au/your-environment/air

The Queensland Government air quality website:

http://www.qld.gov.au/environment/pollution/monitoring/air/

State Law Publisher (Western Australia):

http://www.slp.wa.gov.au/Index.html

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