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Air - NSW overview

Approved methods for the sampling and analysis of air pollutants in NSW FAQ

 

Introduction

The Approved methods for the sampling and analysis of air pollutants in NSW (AMSAAP) lists the statutory methods that are to be used to sample and analyse:

  • air pollutant emissions from stationary sources (including continuous monitoring)
  • pollutant emissions from motor vehicles
  • components in, and properties of, petroleum products.

Methods are also listed to test for pollutants in ambient air.

In relation to sampling and analysis of air emissions from industrial and commercial premises, the methods specified in AMSAAP are referred to in Part 5: 'Air impurities from emitted activities and plant' in the Protection of the Environment Operations (Clean Air) Regulation 2010.

AMSAAP may also be referred to in conditions attached to statutory instruments such as licences or notices issued under the Protection of the Environment Operations Act 1997.

Download the document

Approved Methods for the Sampling and Analysis of Air Pollutants in NSW (AMMAAP):
Available as PDF - amsampling05360.pdf, 297 kb; requires Acrobat Reader

Application to use alternative methods to those in AMSAAP

My licence requires me to sample a particular air pollutant at an identified discharge point but doesn't specify which method to use. Can I use any method?

No, the approved methods should be used in all cases, except where the licence condition specifically requires or allows for the use of alternative method(s). The Chief Scientist of the EPA can approve use of alternative methods in 'exceptional circumstances'.

What has to be included in an application to the Chief Scientist to use alternative methods?

The specific circumstances are considered on a case-by-case basis. It is essential to establish the particular circumstances that justify the use of a method other than the approved method(s). The underpinning case for an alternative method has to be clearly established, otherwise the application may not be considered further. Further guidance on what is expected in an application is given in section 1 of AMSAAP.

Selection of sampling positions (TM-1)

What criteria define a suitable location to take a stack sample?

Approved method AS 4323.1-1995 is the method that can be used at all industrial premises under all circumstances. However, USEPA Method 1 is an alternative approved method suitable for use under approved circumstances, as outlined in section 2 of AMSAAP.

AS 4323.1-1995 (the 'Standard') outlines two considerations for locating a suitable sampling plane: physical location and characteristics for suitable gas flow.

Location criteria

The further the sampling plane is from a disturbance to emission gas flow, such as a bend or a fan, the more suitable the gas flow characteristics will be for sampling at that location. The Standard specifies how close to a flow disturbance a sampling plane can be located.

Two types of sampling plane location are described in the Standard: ideal and non-ideal. A third type of sampling plane can be inferred, which is a non-compliant sampling plane.

An 'ideal sampling plane' complies with the minimum distances specified in Table 1 of the Standard. An ideal sampling plane complies with the Standard and must be used if it is available.

A 'non-ideal sampling plane' is closer to a flow disturbance than specified in Table 1, but uses an increased number of sampling points to compensate for the disturbance, as specified in Table 2 of the Standard. A non-ideal sampling plane complies with the Standard.

A 'non-compliant sampling plane' does not comply with the Standard because it is too close to a disturbance to allow reliable measurement. A non-compliant sampling plane:

  • is closer than one duct diameter upstream of a bend, or
  • is closer than two duct diameters downstream of a bend, or
  • does not meet criteria (a) to (f) in section 4.1 of the Standard.

Flow criteria

In addition to the location criteria are flow criteria. These describe gas flow direction, velocity, flow profile across the duct, and temperature and pressure characteristics of the gas stream. These criteria must be met for a sampling location to be considered acceptable and compliant with the Standard.

What alternative method is available for existing stacks that cannot meet AS 4323.1-1995?

It has been recognised that many existing industrial stacks have been constructed so that the location criteria in AS 4323.1-1995 cannot be met. To acknowledge this, AMSAAP specifies approved circumstances in which USEPA Method 1 can be used as an alternative method for determining a sampling plane location.

In particular, USEPA Method 1 provides for sampling in a location that is sufficiently close to a flow disturbance that it would be considered non-compliant with AS 4323.1-1995. However, using USEPA Method 1 sampling at such a location is acceptable only if, it can be demonstrated that certain gas flow criteria outlined in the method can be achieved.

Does upgrading or renewing an existing piece of equipment change the requirements for the sampling position?

Upgrading or renewing equipment generally provides an opportunity to ensure a sampling plane compliant with AS 4323.1-1995 is made available. For example, if the work includes renewing the existing stack, this would be considered an appropriate opportunity to construct a new stack that is compliant with the requirements of the Standard.

However, if the work is limited to upgrading equipment upstream of the emission point but retains the existing infrastructure of the emission stack, the requirements of the sampling position remain those applicable to the existing infrastructure.

Emissions of hydrogen sulfide from stationary sources (TM-5)

How can USEPA Method 11 be modified to enhance the sensitivity of detection?

AMSAAP nominates a variety of methods for sampling and analysis of hydrogen sulfide in stack emissions. The methods vary in a number of ways, including sensitivity of detection. In particular, USEPA Method 11 is considered a cost-effective method, but one disadvantage is that the sensitivity may not be adequate to demonstrate regulatory compliance. However, there is scope within the method to improve the sensitivity.
The nominal sampling time required in the method is at least 10 minutes. This sampling time can be legitimately increased to allow capture of hydrogen sulfide from an increased gas stream volume, thus having the effect of reducing the low limit of detection. However, care needs to be taken to ensure that the capture solutions are not saturated during the increased sampling time. This modification is considered to be within the scope of the method without needing the approval of the Chief Scientist to use this as an alternative method.

Emissions of oxides of nitrogen from stationary sources (TM-11)

Which instrumental analysers can be used to determine the concentrations of oxides of nitrogen?

Approved method USEPA Method 7E requires a sample to be continuously extracted from the gaseous stream. A fraction of the sampled stream is conveyed to an instrumental analyser for determination of the concentrations of nitric oxide (NO) and oxides of nitrogen (NOx). The method nominates use of a chemiluminescence analyser. However, as noted under TM-11 of AMSAAP, the EPA recognises the use of any appropriate instrumental analyser for determination of NO and NOx concentrations, provided the performance specifications of USEPA Method 7E are met to ensure reliable data. The instrumental analyser must also measure both NO and NOx directly.

How can concentrations of oxides of nitrogen be reported?

Determination of emissions of oxides of nitrogen from stationary sources using an instrumental analyser in accordance with USEPA Method 7E results in direct measurements of NO and total NOx. Following from this, the concentration of NO2 can be calculated as the difference between measured NO and NOx. This data can be reported directly or, if required, converted into an equivalent NO2 concentration. Details of these calculations are given in Appendix I of AMSAAP.

Odour sampling and analysis (OM-7 and OM-8)

What is the measurement unit for odour?

Odour is expressed as a concentration, and is represented as a number of 'odour units' (OU). One OU is defined as the minimum concentration of the substance that causes a positive physiological response in a reference panel of individuals.

Continuous emission monitoring (CEM) methods

What are the cycling times and data recording requirements?

For opacity – Minimum of one cycle of sampling and analysis for each successive 10-second period and one cycle of data recording for each successive 6-minute period.
For all CEM systems except opacity – Minimum of one cycle of operation (sampling, analysis and data recording) for each successive 15-minute period.

What are the averaging period requirements?

Except as otherwise specified in the relevant environment protection licence (under clause 28(2)(b) of the Regulation), the averaging periods to be used are:

  • For opacity – All data shall be reduced to 6-minute averages calculated from 36 or more data points equally spaced over each 6-minute period.
  • For all CEM systems except opacity – All data shall be reduced to 1-hour averages calculated from four or more data points equally spaced over each 1-hour period.

What monitor downtime is acceptable?

As a guide, the minimum data capture for opacity monitoring should be 95%, and for all other CEM systems, 90%. This allows a reasonable period of monitor downtime in the following situations:

  • monitor breakdown
  • scheduled monitor maintenance
  • daily zero and span checks
  • performance specification testing.

Case study

Example calculation of emissions from combined sources

A licensed pulp and paper mill is operating a lime kiln fired on timber waste, a kraft recovery boiler fired on solid fuel (boiler 1) and a gas-fired power boiler (boiler 2) all of which discharge through a single main stack. Each emission unit belongs to Group 6 under the Regulation.

What is the oxides of nitrogen standard of concentration and reference oxygen concentration for the main stack if all three emission units are operating?

The applicable standards of concentration for emission of oxides of nitrogen (NOx) for each individual emission unit are specified in Schedule 3 of the Regulation, under 'Paper, paper pulp or pulp products industries'. The oxygen reference level that applies to each emission unit is specified in Schedule 5, Part 3 of the Regulation. The volumetric flow rate of each emission unit is also known. This information is summarised below:

Emission unitNOx standard of concentration (CN) (mg/Nm3)  Oxygen reference concentration (ON) (%)Volumetric flow rate (qN) (Nm3/s)
Boiler 1 (solid fuel) 300735
Boiler 2 (gas fuel)300350
Lime kiln (solid fuel)40075

 

The alternative standard of concentration for a combined source (Cr) is calculated as follows:

(1)

         C1q1 + C2q2 + ........ + CN qN
Cr =  _________________________
             q1 + q2 + ........ + qN

where:

C= the standard of concentration applicable to the Nth emission unit
 qN  =  the volumetric flow rate of the Nth emission unit

Using Equation 1, the oxides of nitrogen alternative standard of concentration for the main stack is:

         Cr =    300 x 35 + 300 x 50 + 400 x 5 
            35 + 50 + 5 

=   27500 
     90

= 305.5

= 306 mg/Nm3 rounded to the nearest integer


The reference oxygen concentration for a combined source (Or ) is calculated as follows:

(2)

         O1q1 + O2q2 + ........ + ON qN
Or =  _________________________
             q1 + q2 + ........ + qN

where:

O =  the reference oxygen concentration applicable to the Nth emission unit
 qN  =  the volumetric flow rate of the Nth emission unit

 Using Equation 2, the reference oxygen concentration for the main stack is:

          Cr =    7 x 35 + 3 x 50 + 7 x 5 
                   35 + 50 + 5 

=   430 
     90

= 4.77%

= 5% rounded to the nearest integer

 

305.5 mg/Nm3 @ 4.77% O2 = 305.5 x    (21 - 5)    = 301 mg/Nm3 @ 5% O2                   
   (21 - 4.77)

The oxides of nitrogen standard of concentration for the main stack, when all three emission units are operating, is 301 mg/Nm3 @ 5% O2

What is the oxides of nitrogen standard of concentration and reference oxygen concentration for the main stack if boiler 1 is shut down?

Using Equation 1, the oxides of nitrogen alternative standard of concentration for the main stack is calculated assuming CN  and  qN  for boiler 1 is zero:

        
Cr =   300 x 50 + 400 x 5 
           50 + 5 

=   17000 
     55

= 309.1

= 309 mg/Nm3 rounded to the nearest integer


Using Equation 2, the reference oxygen concentration for the main stack is:

        
Cr =   3 x 50 + 7 x 5 
           50 + 5 

= 3.36%

= 3% rounded to the nearest integer

 

309.1 mg/Nm3 @ 3.36% O2 = 309.1 x    (21 - 5)    = 315 mg/Nm3 @ 5% O2                   
   (21 - 3.36)

The oxides of nitrogen standard of concentration for the main stack when boiler 1 is shut down is 315 mg/Nm3 @ 3% O2

Page last updated: 18 June 2013