Development, Wellington.
6. Bailey, M.L. (Nov 1985), "Disposal Options for Polychlorinated Biphenyls (PCBs)", Technical Paper No. 1985/2, Commission for the Environment, Wellington.
APPENDIX 1
TERMS OF REFERENCE FOR THE HAZARDOUS WASTES TASK GROUP
1. To promote the hazardous waste management strategy recommended by the Interdepartmental Working Party on the Management of Hazar- dous Wastes. The essential elements of this strategy are:
(a) A survey of hazardous waste
production and existing management practices in each region or district; this includes instances and opportunities for waste reuse, low-waste technol- ogy and waste reduction, and treatment to make wastes less hazardous.
(b) An investigation of existing and potential sites in each region to determine their suitability for hazardous waste treatment and disposal.
(c) The preparation of a manage- ment plan in each region to state that wastes will go where and under what conditions in con- sultation with industry and other interested parties.
(d) The implementation of the plan by agencies identified in the plant in accordance with defined operational procedures.
2. To monitor the suitability of the above strategy, and recommend modifications where appropriate.
3. To encourage support from central government to provide local and
regional authorities with advisory, research, training and specialist technical services.
4. To investigate appropriate economic instruments to enable pro- gress to be made in the management of hazardous wastes.
5. To investigate changes and additions to legislation in order to strengthen and allocate respon- sibilities for hazardous waste management.
6. To investigate further work necessary to ensure suitable management and disposal of wastes which need a national solution, such as PCBs. This would take into account the work already done by the interim task force on PCBs.
7. To investigate and produce a stragegy for waste reduction and the use of low-waste technologies.
8. To monitor the progress of 107 above and report to the Interagency Co-ordinating Committee on Hazardous Substances and/or the Secretary for the Environment, as and when appropriate.
TABLE 1:
FUNCTIONAL RESPONSIBILITIES FOR MANAGEMENT OF HAZARDOUS WASTES
CENTRAL GOVERNEMENT
Provision of technical support to regional government including planning design and siting facilities; management of specific wastes.
Encourage development of regional management strategies. Maintain a group of specialists to support regional government.
Make necessary legislative changes.
Promote an educative programme through seminars and training courses.
Provide financial incentives such as Department of Health grants scheme.
REGIONAL WATER BOARDS
To safeguard natural waters from uncacceptable leachate contamination.
To provide information to regional government on hydrol- ogy, natural waters and soil characteristics when pro- posals are being investigated.
REGIONAL GOVERNMENT
To be responsible for the development and implementa- tion of a regional management strategy for all wastes generated within their region.
To develop and operate facilities in their own right to delegate the responsibility to a local authority on waste management committee.
To establish a position for a regional waste officer to super- vise waste management within the region and to liaise with local government, central government and industry.
To take cultural and community values into account.
LOCAL AUTHORITIES To identify wastes generated within their boundaries.
To liaise and cooperate with regional government in regard to all aspects of waste management.
To develop and operate facilities in their own right or in conjunction with other local authorities in the region.
To take cultural and community values into account.
NOTE: The above model is particularly applicable to regions of major population and industry and should be modified as appropriate in other cases.
The role of private enterprise is not reflected in the model, however, it must operate under the supervision of regional government.
1 0 8 Clean Air/August 1988
Dr. Basden is retired from the Univer- sity of NSW and is now a consultant.
He is the Honorary Treasurer of the Society.
PREAMBLE
An accompanying report in this issue of Clean Air lists the activities of the Standards Association of Australian Committee CH/19. Among these activities it may be observed that a draft standard is being considered with the title "Ambient Air - Determination of Suspended Particulate Matter (PM1 0) High Volume Sampler with Size Selec- tive Inlet, Gravimetric Method".
In working on this draft the Commit- tee was aware of the impending changes to be made to the U.S.
Ambient Air Quality Standards [1-6].
In these changes the primary and secondary national ambient air quality standards for particulate matter, measured as "total suspended particu- late matter" or TSP, were to be amen- ded to new values related only to particles of size equal to or less than
lOjum aerodynamic diameter. Accor- dingly, it was considered to be highly desirable that Australia should have a standard both for instrumentation and for a methodology to perform a similar functiuon, so that results and other data taken would be intercomparable with that of the U.S. systems introduced to conform to the new standards.
It was at this point that two problems arose, and those were firstly to define precisely what was meant by " P M1 0" , and secondly to define the performance characteristics of a size selective inlet (SSI) which would, if possible, be com- patible with a type fulfilling the U.S.
requirements. As is generally well known, it is extremely difficult to acquire details of technical information such as that referred to from published papers and reports alone, particularly when the information originates from an overseas country. Personal contact with the persons and organisations
actually engaged in the field of activity concerned is of great assistance in obtaining the information required.
Therefore on three visits to the United States in recent months I attempted to obtain the answers to these queries, and was reasonably successful during the last of these, as I was able to talk to many people actively concerned in the framing and application of the new standards, and to inspect the large wind tunnel facility at the Environmental Monitoring Systems Laboratory, U.S.
E.P.A., Research Triangle Park, North Carolina. I also was invited to visit the large wind tunnel in the Aerosol Science Laboratory of Wedding &
Associates, Inc., at Fort Collins, Colorado, but was unable to fit this into my schedule. This facility is described briefly, however, in reference [3].
The procedure adopted in the U. S. A. for changing various air quality criteria and ambient air quality stan- dards is complex and is described elsewhere [7]. Eventually, however, with the publication of the final decisions on the new ambient standard in the U.S. Federal Register [8] on 1st July 1987 the speculation has ceased.
Although the actual primary and secondary ambient air quality stan- dards are simple to state and to com- prehend, there is, nevertheless, a complex underlying substructure of procedural matters which are by no means clear from an initial reading of the documents. It is the purpose of this report to clarify some of these points in the limited space available.
THE AMBIENT AIR QUALITY STANDARDS AND THEIR METHOD OF DETER- MINATION
The original 1971 Ambient Air Quality standards were measured as TSP as mentioned above, and were as follows. Primary standards; jug/m3 as a 24 hour average not to be exceeded more than once per year, and ju.g/m3 as an annual geometric mean. The secon- dary standard was 150 jug/m3 as a 24- hour average, also not to be exceeded more than once per year. The new PM1 0 primary standards are: (a) 24
hour; 150 ug/m3 with no more than one exceedance expected per year: and (b) annual; 5 0/xg/m3 expected annual arithmetic mean. The secondary stan- dards are the same as the primary stan- dards (a) and (b) just mentioned; i.e.
they involve PM1 0 and not TSP as was proposed in the initial publication for discussion [9]. (In this 1984 Federal Register/9/ the proposal was to amend the 24-hour secondary standard men- tioned above to an annual TSP stan- dard to be selected from a range of 70 to 90 jug/m3 expected annual arithmetic mean. However, for reasons set out at some length in reference [8] this pro- posal was rejected in favour of that just described).
One of the first questions to arise is what exactly is PM10? The answer is that it is that fraction of the airborne particulate matter which passes through a specially-designed inlet attached to the sampler, which gives a 50% cut point of 10.0 ± 0.5 /im aerodynamic diameter. (Note that earlier proposals were discussing 10.00 ± 1.0 jurn, but this has been altered). In addition, the inlet perfor- mance requirement is prescribed as a functional specification rather than a design specification so as to allow manufacturers of air samplers flex- ibility in design. The performance specification is that "the expected mass concentration calculated for a can- didate PM1 0 sampler when sampling a specified particle size distribution, be within + 1 0 percent of that calculated for an ideal sampler whose sampling effectiveness is explicitly specified".
The sampling effectiveness of the ideal sampler referred to above is defined or 'explicitly specified' in the Federal Register/70/, and is based on a model that approximates the penetra- tion of particles into the human res- piratory tract based on the work of Chan and Lippmann [11]. The tabulated figures of particle size versus sampling effectiveness of the ideal sam- pler, when plotted, yields the curve illustrated in Figure 1. The abrupt end of this curve at a particle size of 16 jiim may be noted, but during the public penetration cut-off was recommended at various values between 15 and 25 fj/12]. However, when a test or can- didate sampler is to be tested for com- pliance with the performance specification described in the paragraph above against the approp- riately sized liquid aerosol particles at a prescribed wind velocity (q.v.), the instructions are to: 'extrapolate the upper and lower ends of the corrected liquid particle sampling effectiveness curve to 100 percent and 0 percent, res-
cent. Later the collected fractions are corrected for the percentages of mul- tiplets, i.e. agglomerates consisting of doublets or triplets). As is weli known the GSD of a truly monodisperse sys- tem is 1.0, therefore the specification is for a very close to monodisperse system which the vibrating orifice aerosol generator is capable of producing. The aerosol suspension in the tunnel is analysed or checked for size distribu- tion characteristics by optical micros- copy, for which detailed procedures are provided [16]. Each of the 10 size increments of aerosol is utilised with each of three wind speeds in the tunnel, namely 2, 8 and 24 km/hr. The liquid aerosol is used over the complete range, whereas the solid aerosol is used for the 25 ± 1.0 ju.m particle size and for the 8 and 24 km/hr wind speeds only.
Furthermore, there are to be at least 3 determinations for each combination of particle size and wind speed, which means a minimum of 96 determinations of penetration through the SSI for a complete acceptability test. The pro- portion of material collected on the filter after passing the SSI is deter- mined by fluorometry; hence the use of uranine dye and ammonium fluores- cein as previously described.
In order to calculate what percen- tage of the aerosol has been captured by the SSI for each of the minimum of 96 tests just described, the actual aerosol concentration in the air stream, in each case, must be determined. This is done by inserting an array of at least 5 independently controlled isokinetic sampling heads into the airstream, in the tunnel in the same position, but prior to, the introduction of the SSI and sampler. (The array of isokinetic sam- plers in the Research Triangle Park wind tunnel consisted of 7 units, in 3 rows of 2, 3 and 2 units respectively).
The mass concentration of particulate for each isokinetic sampler is deter- mined, and from these the coefficient of variation between all isokinetic heads is found by applying a given method. If this exceeds 0.10, the uniformity of the particle concentration across the test zone is unacceptable so the procedures must be adjusted and repeated. If the result is acceptable, this then gives the actual or true aerosol concentration, so the amount subsequently recovered by the sampler through the SSI may be expressed as a percentage of this concentration.
After collecting these data, three sets of graphs are constructed on semilogarithmic graph paper (one for each wind speed) of sampling effective- ness on the linear ordinate (expressed as a percentage) versus particle size on
the logarithmic abscissa. Each graph therefore will consist of at least 30 experimentally determined points, (and 33 for the 8 and 24 km/hr plots) through which a smooth curve is con- structed. (No curvilinear regression formula is provided for this purpose so presumably the experimenter could adopt a method of personal pre- ference). As mentioned above the curve is to be extrapolated in each direction to 100% at 1.0 jum and 0% at 50 jum. From each of the three curves so obtained, a value of sampling effec- tiveness is readforeach of 37 values of particle size between 1.0 and 45.0 fim (initially in 0.5 increments at the low values but increasing to 5 increments at the higher values) and these are inser- ted in a column in matrix array consist- ing of 37 rows and 7 columns. By operating on elements in each row the matrix array is completed from which the expected mass concentration of the test sampler, for the wind speed con- cerned, is found as the sum of the 37 elements in one of the columns. This is then compared with the pre-calculated mass concentration of the ideal sampler (based on the curve of Figure 1) which is provided as the sum of corresponding elements in the 7th column of the mat- rix. The sampler passes the test if for each of the 3 graphs the following applies:
(i) The liquid particles mass concen- tration falls within ± 10 percent of that of the ideal sampler.
(ii) For the solid particles the sampling effectiveness is no more than 5 per- cent above that of the correspond- ing sized liquid particles.
(iii) The 50 percent cut-point is 10 ± 0.5 fim aerodynamic diameter.
CONCLUDING COMMENTS From what has been described above it is apparent that the testing of a new size select inlet for compliance with the standard would be an extremely costly and time consuming procedure, even assuming that an appropriate wind tun- nel, equipped with the specified instrumentation (along with a back-up aerosol testing laboratory) happened to be available. Accordingly, one could be excused for believing from a cursory reading of Part 53.34 of reference [8]
that a simpler alternative procedure is available. This Part states that three candidate samplers could be collocated with three 'standard' or approved reference method samplers to collect a minimum of 15 sets each of simultaneous 24-hour PM1 0 samples at each of two test sites; i.e. 180 samples in all. When these are analysed and the
Clean Air/August 1988
results subjected to the stated statistical procedures, the candidate samplers pass the test if the following conditions are met:
(i) Acceptable concentration range:
30 to 500 jug/m3.
(ii) Precision of replicate 'reference method' measurements: ^ig/m3 or 7 percent,
(iii) Slope of regression relationship: 1
± 0 . 1 .
(iv) Intercept of regression relationship: 0 ± 5 u.g/m3
(v) Correlation of reference and can- didate method measurements >
0.97.
Unfortunately, however, I was advised during discussion with Larry Purdue and Ken Rehme at the E.P.A.
Environmental Monitoring Systems Laboratory that this is not the case for new or candidate SSIs attached to filtration-gravimetric type samplers.
Instead, this procedure is provided for the approval of a different type of assessment device (e.g. beta- attenuation or a light scatter instru- ment) attached to an already approved SSI. For a new SSI-sampler combina- tion there apparently is no escape from the wind-tunnel procedure as a means of gaining approval.
At the moment in the U.S.A. there are only two contenders for the PM-i0 SSI market; namely the Andesen (or Sierra-Andersen) whose principal aerosol dynamicist is Dr. A.R.
McFarland of the Texas A & M University at College Station, Texas (and at which location I understand the development work and wind tunnel testing of the Sierra-Andersen inlet has been conducted); and the Wedding, whose principal aerosol scientist is the ex-academic founder of the company.
Dr. J.B. Wedding. Wedding &
Associates Inc. have constructed their own aerosol science laboratory com- plete with wind tunnel (spoken of in glowing terms by those who have seen and used it - and not all have been from the Wedding organisation) in Fort Collins, Colorado. I do not wish to relate the pros and cons of these two quite different types of sampling instruments which I may have acquired during casual conversaions, but it is evident quite readily from the published literature [17][18](also references [2] to [6]) that there is (or was) disagreement between the results obtained from each type of sampler.
The Sierra-Andersen apparently sam- pled high, the cause of which, in all pro- bability, was alleged to be by particle bounce and re-entrainment from the impaction substrate, even when the lat- ter was oiled. The Wedding, on the
other hand, apparently was inclined to sample low, the cause of which was postulated to be produced by particle build-up on the cylindrical walls of the cyclonic inlet duct, and thereby inter- ceping particles which otherwise would have passed through. (The previous two sentences were written in the past tense because by now, in all pro- bability, a solution to the discrepancy problem may have been effected by each manufacturer and I would not wish to be guilty of making statements which may not now apply).
Monitoring Systems Laboratory, U.S.
Environmental Protection Agency, Research Triangle Park, N.C, 12 pp (1987).
18. E.R. Kashdan, M.B. Ranade, L.J. Pur- due and K.A. Rehme, 'Interlaboratory Evaluation of Two Inlets for Sampling Par- ticles less than 10 ^um', Environ. Sci.
Technol. 20 (9) 911-916 (1986).