VOLUME 13, No. 1, FEBRUARY, 1979. PRICE. $2.00
listing as a publication (Category B)
l/o/. 13, No. 1, February, 1979
EDITORIAL
Ken Sullivan A2
WERNER STRAUSS MEMORIAL LECTURE TECHNICAL PAPERS
Ozone Levels in Sydney 1975-77.
A Statistical Evaluation
L. M. Ferrari, R. A. Hayes, D. Johnson and G. Michalk The Australian Initiative in Baseline Monitoring
L. Wainwright
Canada's Air Pollution Control Program R. M. Robinson
FEATURES IUAPPA news Branch News Company News Book Reviews
5
11
10
10
10 14
JOURNAL OF THE CLEAN AIR SOCIETY OF AUSTRALIA AND NEW ZEALAND President: H. F. Hartmann
Secretary: R. W. Manuell, Box 191, Eastwood, N.S.W. 2122.
EDITOR R. G. Gillis
EDITORIAL BOARD H. F. Hartmann S. J. Mainwaring J. O'Heare K. L. Sullivan B. R. Thiele EDITORIAL OFFICE 75 Downshire Rd., Elsternwick, Vic, 3185 Australia
ADVERTISING Appita
191 Royal Parade Parkville 3052 Enquiries: Mrs Lorraine Geal Phone: (03) 347 2377 PRINTER
Advocate Press Pty. Ltd. 329 6588
Publication is quarterly in February, May, August and November.
Annual Subscription rates (inc.
postage) for non-members and libraries:
Australia $A6.75 U.S.A. $US12.00 U.K. Six Pounds Germany DM30.00 Elsewhere $A8.50 Single Copies $A2.00
Subscriptions and subscription enquiries should be directed to the Circulation Manager,
Mr. A. Crapp, Box 191 Eastwood, N.S.W. 2122 Australia
Phone: (02) 646 0363
'Clean Air' is listed in Current Contents and Environmental Periodicals.
A2
EDITORIAL
Clean air or energy, surely it is not going to be a matter of priorities.
Air emissions largely occur as a result of energy usage. The Australian p a t t e r n of energy use, and in particular, the availability of liquid fuels for transport is changing rapidly.
Conservation of energy and economy of use are becoming of p r i m e i m p o r t a n c e t o t h e c o n t i n u e d maintenance of the life style that we in this country enjoy.
The need for change is due to the imbalance t h a t exists between availability and use of solid, liquid and gaseous fuels. To rectify this imbalance, petroleum will need to be conserved for use as a transport fuel.
Additional liquid fuel-will be required to meet our transport needs and this will be derived by converting other, indigenous energy sources. The needs of industry will largely be met by using readily available local fuels.
If we are to survive into the next century, with a considerable degree of self-sufficiency, we cannot afford to waste our comparatively limited resources of energy. Efficiency of utilisation will be an a b s o l u t e requirement.
The need for energy rationalisation and conservation will cause change.
Motor vehicle gasoline consumption must be reduced. This will result from improved operating efficiency and the increasing use of smaller vehicles.
However, air pollution control devices can, and at present, are reducing vehicle efficiencies. This specific problem is being closely looked at by government committees and hopefully will be resolved so that clean air and energy savings are both achieved.
Industry's energy needs will largely be met by indigenous fuels, which "will mean a considerable increase in the use of coal. However, this change need not cause air pollution. Fortunately Australian coals are comparatively low in sulphur, whilst oxide of
nitrogen emissions arising from the combustion of our coals, have been found to be significantly less than those reported from their northern hemisphere counterparts. Moreover, smoke and solid particulate emissions, which could occur with coal firing, may be controlled by plant design and operation.
Action to effect air pollution control originally stemmed from the poor, inefficient combustion of fuel.
In the intervening years, effective controls and fuel changes have played a part in ensuring cleaner air. The future will again require changes, this time with the emphasis being on fuel efficiency and economy. It is important that coinciding with these changes, clean air be maintained.
KEN SULLIVAN President, N.S.W. Branch.
WERNER STRAUSS MEMORIAL LECTURE
A proposal to establish a Werner Strauss Memorial Lecture was agreed by the Executive Committee at its November 1978 meeting. It was decided that the first Lecture would be given in Victoria during 1979 and thereafter the Lecture would be a focal point at each triennial Conference.
Professor Arthur Stern, who had been working in the Philippines and then came to Australia, agreed to be the Inaugural Lecturer. The Lecture was delivered at a joint meeting with the Society of Chemical Industry of Victoria (of which Dr. Strauss had also been an office bearer) in the G r e e n w o o d L e c t u r e T h e a t r e , University of Melbourne on the evening of 8th February, 1979. Staff members of M.U. Departments of Chemical Engineering, Applied Science and Environmental Studies also attended. It is planned to publish the text of the Memorial Lecture in a- later issue.
F o l l o w i n g the L e c t u r e , the President of the Clean Air Society, Mr. H a n n s H a r t m a n , m a d e a posthumous presentation of the Society's Clean Air Medal to Mrs. J.
Strauss.
CORRECTION
In the report on the 1978 Convention, Dr. K. Spurny was incorrectly indentified as Prof. Fritz Loffler in the picture with the late Dr. Strauss (P- 48).
OZONE LEVELS IN SYDNEY 1975-1977, A STATISTICAL EVALUATION
Len M. Ferrari, Ross A. Hayes,
David Johnson and Graham Michalk
The authors are Technical Officers of the State Pollution Control Commission (SPCC) of New South Wales.
INTRODUCTION: The Clean Air Branch of the State Pollution Control Commission (SPCC) of New South Wales, began continuous monitoring of ozone in the Sydney area in 1971, coinciding with severe ozone damage to seedlings in the Parramatta River Valley. Data from a number of monitor sites in urban Sydney has grown rapidly since the end of 1974.
This paper presents a statistical summary of over 80,000 hours of data.
The results show that photochemical smog, far from being confined to a narrow corridor in the Parramatta River Valley, spreads south, east and west t o t h e o u t s k i r t s o f t h e metropolitan area.
SAMPLING
The monitors used were the gas phase chemiluminescent type. Subsequent
"eyeball" averaging of the analogue traces from the chart recorders yields the one hour average data. This was then transferred to a computer for analysis.
The monitors were originally calibrated using the Potassium Iodide Method (1) and from January 1977 using the Gas Phase Titration Method of De Moore et al. (2) Data measured before 1977 have been adjusted to agree with the new calibration procedure.
SITING OF MONITORS
The fixed monitor sites are shown on the accompanying map (Fig. 1) and all lie within the Sydney Basin, a seaboard metropolitan city of latitude 34° south, an area of approximately 5000 km2 of relatively low ground at the bottom of the dishlike topography.
The population of about three million drive approximately one million motor vehicles. Within the Sydney Basin, meteorological phenomena create numerous local air movements that dictate a considerable spatial variation of ozone levels.
Historically, the Lidcombe site, established in 1971, has been used as
the indicator of Sydney's urban ozone levels. Recent d a t a show t h a t Lidcombe does not experience the highest ozone concentrations when compared with some other sites in the Sydney Basin.
T h e W a r w i c k F a r m a n d Campbelltown monitors in the south- west region were established only in later years when it became evident that parcels of air from high source areas of precursors frequently drifted there later in the day (3). The Campbelltown site is subject to a wide separation of greenbelt from the p r i n c i p a l Sydney m e t r o p o l i t a n complex. The Warwick Farm site lies on the metropolitan border of this greenbelt change.
DATA AND DISCUSSION
Much of the data presented below is in graphical form using a log probability scale on the x-axis. These cumulative percentages represent data for ozone levels exceeded, r a t h e r t h a n conventional (cumulative) percentages for values less than.
A recommended treatment of the statistical aspects of air pollution and other relevant statistics, especially of log-normal distributions can be found in Zimmer, Tabor and Stern (4).
When the cumulative frequency distributions of ozone frequencies are plotted on normal probability paper they show a strong skewness in the low values. Low readings (about 95%
below 6 pphm) occur during periods of darkness, rain or high dispersion.
Fig. 2 shows the plot of the cumulative frequency distribution of ozone values from 3 urban Sydney sites over 3 years a g a i n s t log probability. The line of best fit by least squares is computed by using the logarithm of the ozone concentration, for frequencies above 2 pphm, as the r - a x i s , and a n o r m a l d e v i a t e corresponding to the cumulative percentage, as the x-coordinate. The value of the correlation coefficient is 0.993, validating the assumption that the aggregated readings are nearly log-normal in distribution.
Figure 1 Stationary Ozone Monitors—Sydney Basin 1975-1977
The line of best fit is used to estimate the parameters of the distribution. The geometric mean (50th percentile) = 3.6 pphm, and the standard geometric deviation (one standard deviation transformed to logarithmic units) = 2.2 pphm. Ozone measurements in the basin, showing occasional values around 30 pphm each year are now reinforced by the straight line plot of all the values measured which extrapolate to l- hourly maximum of about 30 pphm.
Averaging the years 1975, 1976, 1977 and the three sites, the World Health Organisation (WHO) one- hour goal was exceeded 5.5% of the time, while the United States EPA standard was exceeded more than 2.5% of the time. The much higher 15 pphm level exceeded just in excess of 0.3% of the time.
The 8-hour averages used in Fig. 3 are sampled from overlapping 8-hour periods computed from the start of each hour. The WHO 8-hour goal was exeeded over 20% of time on average
F i g u r e 3 C u m u l a t i v e F r e q u e n c y . Distribution Sydney Ozone Aggregate Of 3 Years and 3 Urban Sites Log Probability Plot (eight-hour averages)
F i g u r e 2 C u m u l a t i v e F r e q u e n c y Distribution Sydney Ozone, Aggregate of 3 Years and 3 Urban Sites, Log Probability Plot (One-hour samples)
at the 3 aggregate sites. Studies elsewhere in NSW have demonstrated that this goal can be frequently exceeded in rural areas also (5).
The vertical lines on the frequency p l o t s for L i d c o m b e a n d Wentworthville at the maximum indicates that no days in the period recorded values between 26 pphm and 30 pphm but that 1 day and 2 days respectively exceeded ozone levels above 30 pphm. The Marrickville site experiences a g e n e r a l l y larger proportion of days at the higher ozone levels although this trend is not maintained at either extreme.
The average number of days per year that the WHO one-hour goal is exceeded is 103 at Wentworthville, 98 at Lidcombe and 90 at Marrickville. It is important however to look at days when photochemical smog reaches more severe levels. Over the three years, on average, Lidcombe exceeded
15 pphm on 9 days, Wentworthville on 10 days and Marrickville on 12 days.
In 1977 new monitoring sites were established, and the 15 pphm level was e x c e e d e d on 15 d a y s at Campbelltown, 17 days at Warwick Farm and still 9 days at Lidcombe.
Thus the Lidcombe monitoring data does not represent the worst exposure to photochemical smog in the Sydney Basin.
Fig. 5 is based on the average ozone levels measured at L i d c o m b e , Marrickville and Wentworthville during each of the years 1975, 1976, 1977. The graphs for the 3 years show that there is significant variation on a year to year basis particularly at higher levels. When looking at the average number of hours above 15 pphm there are 10 hours in 1975, 45 hours in 1976 and 34 hours in 1977. It could not be argued that during the 3 year period t h e r e has been a significant variation in the overall emissions of ozone precursors. The differences are no doubt due to the vagaries in meteorological conditions.
What it also means is that if next year or the year after is one where the meteorological conditions are very s u i t a b l e for the f o r m a t i o n of photochemical smog, Sydney could experience even more severe levels.
Fig. 6 allows the comparison of the ozone distribution at the 3 component sites used in all the above graphs. The Lidcombe and Wentworthville sites show a clear similarity and linear shape, however the Marrickville site has higher readings and is non-linear.
The Marrickville readings are thus a distribution that deviates from log- normal. It is not obvious why this is so, though there are dissimilarities between Marrickville and the other permanent sites. Some of these are
— the Marrickville monitor is nearer to emissions from local traffic
Figure 4 Percentage of Days Ozone Thresholds exceeded, Sydney Ozone Aggregate of 3 Years at 3 Urban Sites, Log Probability Plot (One-hour samples)
F i g u r e 5 C u m u l a t i v e F r e q u e n c y Distributions Sydney Ozone 1975, 1976, 1977. Aggregate 3 Urban Sites, Log Probability Plot (One-hour samples).
— Marrickville is the nearest site to the seaboard
— Marrickville is nearer to the CBD and local industries.
A t C a m p b e l l t o w n t h e e a r l y morning quenching effect of nitric oxide is not as prevalent in this non- urban locality. Hence, the night time ozone readings will not be as depressed as at the urban sites where lower readings are more frequent.
F u r t h e r , u n d e r c o n d i t i o n s of recirculation of ozone laden air, readings at Campbelltown can remain at elevated levels as they do not suffer the quenching effects of fresh emissions.
Fig. 7 not only clearly shows that Lidcombe gives an underestimation of the amount of pollution in the Sydney Basin on days of high photochemical smog but taken in conjunction with Fig. 6 illustrates the extent of those high levels throughout a significant part of the basin. Many people in Sydney are now exposed to these high levels of photochemical smog.
Fig. 8 illustrates the average number of days per year ozone frequencies are exceeded at one or more sites in the basin. The data used here was derived from the Lidcombe, M a r r i c k v i l l e , W e n t w o r t h v i l l e , Warwick Farm and Campbelltown monitors from 1975 or when the monitors commenced to the end of
1977.
It can be seen that the WHO goal is exceeded on about 161 days and 15 pphm on 27 days. By comparison of the data in Fig. 4 and Fig. 8 it is apparent that measurements from a single site tend to underestimate the magnitude of the problem within the whole network.
Fig. 9 shows the diurnal levels of ozone constructed for the days when the maximum 1-hourly value exceeded
15 pphm. The number of days is indicated in the figure. In considering the total exposure, not only the peak height, but also the area under the curve should be considered.
The nitric oxide quenching effect on ozone overnight and in the early morning traffic peak is clearly seen at L i d c o m b e , M a r r i c k v i l l e , Wentworthville and Warwick Farm but the effect is much less at the non- urban Campbelltown site.
Lidcombe levels reach a peak at about noon and then decrease rather early probably due to increased d i s p e r s i o n and a d e c r e a s e in concentrations of reactive oxidants later in the day.
Campbelltown to the south-west builds up over a long time and peaks at about 3.30 p.m. and then decreases.
The gradual build up is probably due to transport of the urban air mass followed by the arrival of the oxidant laden sea breeze.
Marrickville and Warwick Farm give almost identical (Gaussian shaped) diurnals showing a gradual
F i g u r e 7 C u m u l a t i v e F r e q u e n c y Distributions, Sydney Region Ozone, Comparisons for 1977, Log Probability Plot (One-hour samples)
build up in morning to a gentle peak within the period 12.30-3.30 p.m. and then a decrease. The broad nature of the peak is probably a result of the averaging of a number of peaks over a relatively large time frame and the result of prevailing winds to the sites being relatively rich in precursors and oxidants over that time scale.
The Wentworthville site also approximates a Gaussian shape but with a narrow peak between 1.30-2.30 p.m. The major influence at this site is likely to be the sea breeze.
SUMMARY
1. The Sydney Basin ozone data encompasses an expanding ozone monitoring network that is operated by the SPCC in NSW.
2. The distribution of urban Sydney Basin ozone measurements is nearly log-normal.
3. Historically the Lidcombe site has been used as an i n d i c a t o r to
F i g u r e 6 C u m u l a t i v e F r e q u e n c y Distributions, Sydney Urban Ozone by Site.
Aggregate for 1975, 1976, 1977, Log
Probability Plot (One-hour samples) Figure 8 Frequency of Ozone Maxima in Sydney Network, Maximum Ozone for each day from Combined Sites, Log Probability plot (One-hour samples)
Fig. 9 Diurnal Ozone Variation, Sydney Region Averages when 15 pphm Exceeded (One- hour averages)
Sydneywide measurements, but it has become apparent that Lidcombe is far from the worst area in the basin. In fact no one monitoring site gives a proper picture of the severity of smog in the Basin.
4. WHO goals are frequently exceeded in the Sydney Basin. The 8-hour goal was exceeded 21 per cent of the time over a 3 year average at 3 combined urban sites. The 1-hour goal was exceeded for an average number of days per year of: 148 days at Wentworthville, 98 days at Lidcombe and 90 days at Marrickville. During 1977 a level of 15 pphm ozone (nearly three times the WHO goal) was exceeded on 9 days at Lidcombe, 15 days at Campbelltown and 17 days at Warwick Farm.
Also from the straight line plot of ozone on log probability scales, the maximum 1-hourly value expected in the monitoring network is about 30 pphm. This confirms the field measurements.
5 . F i x e d g r o u n d s i t e o z o n e measurements discussed here (over 80,000 measurements) are only a p o r t i o n o f t h e t o t a l o z o n e measurements collected in the Sydney Region. Other studies, particularly the Sydney Oxidant Study (SOS) are investigating the nature and extent of the oxidant problem, by linking a large set of additional measurements (especially m e t e o r o l o g i c a l and chemical) to the oxidants measured (8). This study together with the data presented here shows that a large portion of the population in Sydney is exposed to high levels of ozone during periods of smog episodes.
For the whole network, averaged over the last three years, the following levels were exceeded at one or more sites each year.
— WHO one-hour goal — 161 days
— 15 pphm for one-hour — 27 days CONCLUSION
The frequency relationship which has been established from the ozone monitoring data will be an important input to the control strategy being developed for the Sydney Region. Any design maximum chosen for strategy purposes can now be related to the frequency of occurrence of any other
ozone level. Further, the likelihood of occurrence of that maximum no longer depends on the uncertainty of an individual reading which can be influenced by the vagaries of the weather or variations in instrument performance.
ACKNOWLEDGEMENTS
Personnel of the Clean Air Branch of the SPCC, in particular the field servicing staff and the tireless lady chart readers, Rob, Eva and Narelle, are warmly thanked for their part.
The collection of the raw data is due solely to the efforts of these people and is the only means by which this analysis became available. Thanks are also due to Geoff Shuttlewood for preparation of the figures. Mr. E. J.
Coffey, Director of the SPCC, is thanked for permission to publish this paper.
REFERENCES
1. Potassium Iodide Method, SPCC Internal Report, Nov. 1973.
2. De More, W. B., and Patapoff, M.,
"Comparison of Ozone Determinations by Ultraviolet Photometry and Gas-Phase Titration", Environ. Sci. Technol.. 10 Sept.
1976.
3. Hyde R. and Hawke G. S., "A preliminary Analysis of the influence of meteorology on ozone levels in S y d n e y " , Smog '76 Conference, Paper V.
4. Zimmer, Tabor & Stern, "Particulate Pollutants in the Air of the U S " , Journal of the Air Pollution Control Association. (Nov.
1959 Vol. 9, No. 3, p. 136 ff.
5 . F e r r a r i L . M . , & J o h n s o n D . C ,
"Photochemical Smog — The Sydney Scene", Clean Air. Feb. 1976.
6. SPCC, "Oxidant Formation Potential 1971, 2000 AD," Annual Report for the year Ended June 30, 1976, page 66.
7. SPCC, Annual and Quarterly Reviews of Air Quality Measurements Since 1971.
8. SPCC, "The Sydney Oxidant Study", Annual Report for the Year Ended June 30,
1977. page 75 ff.
Lewis Wainwright
Engineer
Space Projects Branch
Department of Science INTRODUCTION
The first moves by the World Meteorological Organisation (WMO) to set up global background air monitoring and Australian work in response to the WMO lead are briefly described. The monitoring program is defined and some a s p e c t s are described.
GENESIS
M o s t air m o n i t o r i n g d e t e c t s displeasing or damaging constituents but a "baseline" station is designed to monitor air which is typical of the earth as a whole, i.e. "fresh air". To assess the atmosphere on a global scale some ten to fifteen baseline stations are planned each, as far as practicable, to monitor air which is typical of large clean air masses.
A significant initiative in baseline air monitoring was taken by the World Meteorological Organisation (WMO) in 1971 when it announced a project involving the establishment of a global network for monitoring air pollutants at background levels. A background level is that level which persists in the "background" of the world's atmosphere, those regions unaffected by local sources or sinks such as cities, volcanoes and vegetation.
The 1971 WMO announcement was supported in June 1972 by the United Nations Conference on the Human E n v i r o n m e n t at w h i c h it was recommended that approximately ten baseline stations be set up to monitor l o n g - t e r m g l o b a l t r e n d s i n atmospheric constituents which may cause meteorological or climatic changes. The Australian Government responded to this recommendation by undertaking to provide one of the stations.
PLANNING AND SITE SELECTION
The Australian scientific body had maintained cognizance of baseline monitoring developments and in September 1972, Dr. W. J. Gibbs, Director of Meteorology and Dr. C.
H. B. Priestly, Chairman of the C S I R O E n v i r o n m e n t a l Physics Research Laboratories, prepared a
report setting out the main things to be considered in the preparation for and setting up of the proposed baseline station. The report drew a t t e n t i o n t o s e v e r a l e x i s t i n g Australian monitoring programs which could be validly regarded as parts of a baseline program. It described the internationally agreed plan in which each baseline station would monitor one of the major components of global air circulation.
It named the tropical or sub-tropical easterlies, the temperate westerlies and the Antarctic air masses as the three components available to Australia, but stated that priority should be given to monitoring either the temperate westerlies or the Antarctic easterlies because the US was establishing stations at Samoa and the South Pole. The report noted the cost of an Antarctic station as a d e t e r r e n t a n d s u g g e s t e d t h e Tasmanian highlands as a suitable location for monitoring the westerlies.
In 1975, after surveys and studies of a number of possible sites in the area south of Hobart lying between the Hartz Mountains and the southern coastline, a preferred site was identified near the South East Cape. A t r a n s p o r t a b l e o b s e r v a t o r y was prepared in a large trailer-van but its location at the site was found to conflict or be incompatible with other plans such as those for national parks and forestry. In order to put the observatory to use and gain experience in field work an alternative site was sought which could be occupied immediately at little cost, and which had some potential for baseline monitoring. The site selected was at Cape Grim near the north western extremity of Tasmania. It has been in use since April 1976 and appears to merit development as a permanent baseline station.
Cape Grim is on the west coast and the monitoring location is very close to its highest part, which is 94m above sea level. The site is about 50m from the cliff edge on open grassland with patches of low scrub n e a r b y . Amenities and a workshop are located about 150m to the north east in bush about 2m high (Fig. 1).
THE AUSTRALIAN INITIATIVE IN
BASELINE AIR MONITORING
PREVAILING WIND
Fig. 1 The BAPS instrument Van at Cape Grim viewed from the South East.
Photo—courtesy David Whillas
Wind direction is of p r i m a r y importance to a baseline station situated near sources of pollution such as cities, since valid baseline measurements of most atmospheric constituents can only be made when the wind brings "background" air. At Cape Grim air coming from the 180°
to 300° sector is probably background air, whereas air coming from other directions has probably been affected by the pollution sources, and by the vegetation of either Tasmania or the Australian mainland. The wind diagram, based on twelve months measurements from June 1976 (Fig.
2), shows that Cape Grim was fairly well provided with air from the background sector. Similar wind patterns are expected each year.
However, wind direction measured at the monitoring site is not, of itself, an adequate assurance of background air because the air mass may not have travelled very far in the direction from which it approached the site. A.
number of back-trajectories which have been calculated by the Bureau of Meteorology (Fig. 3) illustrate that two air masses (C and d) arrived at Cape Grim from the same direction but had followed different routes. C would have been a background air mass, whereas d almost certainly have been contaminated. To guard against c l a s s i f y i n g " n o n - b a s e l i n e "
measurements as "baseline", it is intended to consider a number of measurements, such as the total particle count and the carbon dioxide level, in addition to wind direction, when assessing the prevailing air condition at the station.
Fig. 2 Annual mean wind direction frequency distribution, relative to Cape Grim land distribution. Prepared by CSIRO Division of Atmospheric Physics.
THE BASELINE MEASUREMENT PROGRAM
In setting down a "mandatory"
p r o g r a m , WMO has exercised r e s t r a i n t i n o r d e r t o a v o i d discouraging the developing countries from participation. The mandatory program is:
• Turbidity, using an Angstrom-type pyrheliometer or a Volz-type sunphotometer.
• Constituents and characteristics of precipitation:
conductivity and acidity.
• Carbon dioxide.
• A full climatology program.
The non-mandatory part of the p r o g r a m is described as " t h e monitoring of those pollutants which have a potential effect upon global c l i m a t e and t h o s e which have potentially significant effects on other factors of the environment". In Australia this program includes:
• Surface ozone.
• Freon 11, carbon tetrachloride, 1, 1, 1 — trichloroethane.
• Atmospheric particles.
It is planned to include oxides of nitrogen by mid-1978.
CARBON DIOXIDE
It has been established beyond doubt t h a t carbon dioxide has been a c c u m u l a t i n g i n t h e g l o b a l atmosphere since the turn of the c e n t u r y and t h a t i t i s s t i l l accumulating. The present level (1978) is about 330 parts per million parts of air (ppm), and it is increasing by about 0.6 ppm per year.
Although it appears immediately obvious that the burning of fossil fuels is the cause of this increase, other factors may be of similar or even greater importance. One such factor is that the oceans, which hold some sixty times as much CO2 as the atmosphere in the form of carbonates and organic debris, absorb or expel CO, as the water is cooled or warmed.
The changing atmospheric CO2
concentration is important because a substantial part of the earth's r a d i a t i o n is a b s o r b e d by t h e atmospheric CO2 and re-radiated, some of it back to the earth. This has been called the "Greenhouse Effect", although the mechanism is not strictly analagous with that of a garden greenhouse. Estimates of the average
Fig. 3 Trajectories of air parcels at a pressure ievei of 900 mb (about 1 km) during a 48-hour period prior to sampling at Cape Grim.
Prepared by G. Trefry.
temperature rise which would be caused by doubling the atmospheric CO2 vary, but it seems likely that it would be sufficient to seriously affect the agricultural productivity of some important areas of the world.
The CO2 d a t a d e r i v e d from measurements at Cape Grim has been assessed by Dr G. I. Pearman (CSIRO Division of Atmospheric Physics) as being of excellent quality.
Corrections are necessary to the measurements to take account of measuring system characteristics and some data selection is necessary to isolate measurements in air which has been carried over vegetation or inhabited areas. Carbon dioxide concentration is significantly affected by vegetation, which absorbs CO2 by day and expels a lesser amount by night. In this respect it differs from most other atmospheric constituents, and because of this, measurements taken during periods of light wind have been rejected in addition to those taken during periods of non-baseline wind.
The baseline station data will be u s e d , not only to a s s e s s the background level of CO2, and its trend, but also to study global scale concentration gradients and changes caused by local activity such as o c e a n i c c i r c u l a t i o n a n d t h e photosynthesis of plankton in surface waters. At present the imprecision (l) of the global measuring network is too great for the former study, because the reproducibility (l) is between 1 and 2 ppm which is similar to the differences between published mean annual concentrations. Reproducibility of individual measuring systems is smaller, probably about 0.4 ppm, sufficiently good for some studies on the upward trend and variations which may be caused by local activity.
Carbon dioxide measurements are m a d e u s i n g c o m m e r c i a l n o n - dispersive infrared analysers, which compare the infrared absorption of a sample gas mixture with that of a known reference gas. As generally used, these have a reproducibility of between 3 and 4 ppm, but by modification and a t t e n t i o n to calibration methods this can be improved by a factor of about 10 (2).
The analyser at Cape Grim, a URAS 2T (Hartmann and Braun) has a reference cell continuously flushed with a CO2/N2 mixture which itself is calibrated before and after a period of use. The proportion of CO2 in the C O2/ N2 mixture is very close to the proportion of CO2 in air so that the instrument is working close to its
"null point". At hourly intervals two standard CO2/N2 gas mixtures are substituted successively for the
reference gas, one having slightly more than 330 ppm and one slightly less. These are referred to as high and low span calibration gases. The CO2
measurement is thus a continuous record, except for the interruptions caused by the calibration periods.
The calibration mixtures, like the reference mixture, are contained in high pressure gas cylinders. These are made of steel and are cleaned before being filled. After filling the contents are monitored over a period of time to ensure that the mixture has stabilised.
They are then calibrated against mixtures of similar proportions supplied by the Scripps Institution of Oceanography (SIO). SIO has served as a world source of CO2 standard mixtures since 1957 and is likely to become the W M O central CO2 laboratory. The SIO primary analyser uses a series of constant volume mercury manometers for the analysis of primary reference gases.
Problems in setting up the CO2
measuring equipment at Cape Grim arose because laboratory equipment was adapted for field use. This was compounded by the need to automate the measuring and calibrating cycle so that regular measurements could be m a d e i n d e p e n d e n t l y o f s t a f f attendance. The URAS analyser uses a mechanically-varied capacitor as a sensor of pressure difference which is generated by the difference in infrared absorption of the reference gas mixture and the air sample. This capacitor was found to be sensitive to wind buffeting of the instrument van and the analyser was mounted on a pillar extended from the ground through the floor of the van.
OZONE
WMO considers the monitoring of total ozone very important because of its effect on the atmospheric radiation budget and because of the protection it provides from short wave solar radiation. WMO also advocates the measurement of surface ozone because of the detrimental effects on vegetation systems and the concern for the effects of ozone on human health.
Total ozone is not measured at Cape Grim because measurements made by CSIRO from Hobart are representative of a large surrounding region which includes Cape Grim..
Surface ozone measurements are made using a commercial instrument (Bendix model 8002) calibrated by a modified Ehmert method (3). The Ehmert method is a chemical method in which air is bubbled through a solution containing iodide ions which react almost completely with the ozone. The iodine produced reacts with sodium thiosulphate in the solution and the amount of ozone is e s t i m a t e d b y c o m p a r i n g t h e thiosulphate content of bubbled and unbubbled solutions.
The Bendix instrument utilises the chemiluminescent reaction between ozone and ethylene, the light output f r o m w h i c h is s e n s e d by a photomultiplier. The degree of the r e a c t i o n , a n d h e n c e t h e p h o t o m u l t i p l i e r o u t p u t , i s theoretically proportional to the a m o u n t of ozone p r e s e n t b u t calibration from first principles is not
Fig. 4 Measurements of Freon 11 at Cape Grim.
practicable. Uncertainties in the matter of calibration and practical difficulties associated with the operation of the instrument, e.g. the supply of ethylene, have led to the tentative adoption at the US baseline stations of an ultraviolet absorption instrument. This instrument (Daisibi Environmental Corporation) makes a b s o r p t i o n m e a s u r e m e n t s , successively on two samples of ambient air, one of which has been stripped of ozone by a manganese dioxide filter. It is claimed that the calibration of the instrument is absolute, dependent on the Beer- Lambert Law. Nonetheless the US baseline stations are calibrating their station instruments using modified McMillan Electronics Corporation Model 1000 ozone generators as sources of ozonised air with a constant and known ozone content. To ensure that Cape Grim measurements are comparable with those of other baseline stations, a Dasibi ultraviolet absoption instrument has recently been obtained.
HALOCARBONS
Only in recent years have the halocarbons, such as Freon 11 (CCl3F) and carbon tetrachloride (CCl4) attracted the attention of baseline workers. Although stable in the troposphere, they are subject to ultraviolet disintegration in the stratosphere and release chlorine radicals, which are believed to cause catalytic reactions leading to the destruction of ozone.
Although some halocarbons may have natural origins as well as being formed by man, others, notably Freon 11, are believed to have only man- made origins. The detection of Freon 1 1 in background air, and the d i s c e r n m e n t of a very rapidly increasing though still small quantity, has led to questioning the continuation of manufacture and its use in spray cans, refrigeration and industrial processes. Knowledge of its life cycle after release is incomplete and an opinion on the matter is not easily f o r m e d . Scientists working on baseline measurements have been quick to respond to this situation and m e a s u r e m e n t s , which can be correlated, are now being made at a number of places.
Measurement of CCl3F, CCl4 and C H3 CCl3, which is 1 , 1 , 1 trichloroethane also called methyl chloroform, was begun at Cape Grim by Paul Fraser (CSIRO Division of Atmospheric Physics) in 1976. The measurements are made using a s p e c i a l l y d e v e l o p e d g a s chromatograph supplied by J. E.
Lovelock. Its stainless steel column is p a c k e d w i t h 1 0 0 - 2 0 0 m e s h Chromosorb W coated with 12%
dimethylsilicone fluid and the carrier gas is 1% hydrogen in high purity nitrogen The chromatograph uses an electron capture detector which in theory does not require calibration but, in order to facilitate comparison of measurements with those made elsewhere, the instrument is calibrated with standard gas mixtures exchanged with the Washington State University and the NASA Ames Research Centre.
The first 12 months data from Cape Grim, show a Freon 11 concentration of 130 parts per million ppm (i.e. 1 in 1012) at June 1977 (Fig. 4). This is perhaps so little as to be of no consequence, but the data also shows an increase of nearly 20% during the previous 12 months, a trend which is consistent with m e a s u r e m e n t s elsewhere.
OXIDES OF NITROGEN
Nitric oxide and nitrogen dioxide are present in low concentrations in background air (approximately 0.3 parts per billion (109) ). Man's activities contribute to this and are expected to cause an increase of not more than 0.01 ppb per year. To determine whether such a trend exists requires precision higher than that of commercial instruments. A suitable i n s t r u m e n t , u t i l i s i n g t h e chemilummescent reaction between ozone and nitric oxide, is being developed by I. Galbally (CSIRO Division of Atmospheric Physics) and will be installed at Cape Grim this y e a r . Nitrogen dioxide can be measured by conversion to nitric oxide before processing through the same instrument, but some interpretation of the results may be necessary as other compounds containing nitrogen may also be reduced.
AEROSOL PARTICLES
The study of atmospheric particles is vigorously followed in Australia by Dr. E. K. Bigg (CSIRO Division of Cloud Physics). The direct effect of particles on the solar radiation reaching the earth is believed to be of lesser consequence than the cloud- forming properties of certain kinds of particles, since clouds are not only a preliminary to precipitation but also very significantly affect the levels of incoming and outgoing radiation. The program at Cape Grim has been planned to provide information on the nature, properties and quantities of selected particles as well as counting the total number of particles per unit volume of air. As total particle counts were most easily implemented, those were begun first (April 1976) using an exact copy of the Nolan-Pollak counter. In this instrument the air sample is humidified by being passed into a cylinder lined with a wet porous ceramic tube. A light beam is directed through the tube to a photocell, the current from which is a function of the light source and the attenuation of the air sample. The tube is then closed, pressurised with filtered air to 20.9 kPa above atmospheric pressure and, after a 30 second delay, opened to atmosphere. A cloud forms on the tube, attenuating the light beam and changing the photocell current. The ratio of photocell currents, before and after expansion, has been calibrated by Pollak in terms of particle concentration, number of particles per cubic centimetre.
The Nolan-Pollak counter requires manual operation. To obtain regular measurements independently of staff a t t e n d a n c e , a l o c a l l y - d e v i s e d continuously-sampling counter was installed in May 1976. During the remainder of 1976, this instrument showed that Cape Grim experienced
"baseline" particulate conditions, i.e.
less than 700 particles cm-3, for more
than half of the time. On some calm sunny days of winter and spring, a high particulate count, as much as 10,000 particles c m- 3, was measured.
This was traced to kelp deposited on nearby beaches.
P a r t i c l e s a r e c o l l e c t e d for examination by impacting on to electron microscope grids. Those larger than 0.5 μm diameter are collected by direct impaction (1 mm diameter jet placed 1 mm from the grids) sampling occurring about seven seconds every thirty minutes. Very small particles are collected on other g r i d s u s i n g a n e l e c t r o s t a t i c precipitator. The grids with impacted particles are coated in a vacuum chamber with a thin layer of silicon monoxide. The silicon monoxide is deposited in such a way that shadows are cast which are twice as long as the height of each particle. The diameter of each particle is then estimated from an electron micrograph of the grid.
Dr. Bigg has noted that the concentration of particles exceeding 0.5 μm diameter is higher at Cape Grim than is usual at coastal sites, a fact which he attributed to the unusually strong winds at Cape Grim.
The concentration ranges from 1 to 10 c m- 3 and shows some correlation with wind velocity. During strong winds from between south and west, almost the whole mass of the aerosol is sea salt, the particles of which also c o n s t i t u t e s an u n u s u a l l y high percentage numerically of all the particles present (between 2% and 5%).
An instrument for counting "cloud nuclei", the particles which determine the concentration of droplets of natural clouds, is being developed for Cape Grim.
SOLAR TERRESTRIAL RADIATION AND TURBIDITY A fairly comprehensive monitoring progam has been planned by B.
C o l l i n s ( C S I R O D i v i s i o n o f A t m o s p h e r i c P h y s i c s ) . T h e parameters being measured are:
• direct radiation using an Eppley normal incidence pyrheliometer with an equatorial type sun- following mount.
• global short-wave radiation, the sensor being a pyranometer made by Middleton and Co. Pty. Ltd., Melbourne.
• global ultraviolet radiation over the spectral range 290-385 nm, using an Eppley ultraviolet pyranometer,, and
• g l o b a l e r y t h e m a l u l t r a v i o l e t radiation measured by a CSIRO n a r r o w - b a n d u l t r a v i o l e t pyranometer.
It is intended to measure diffuse sky r a d i a t i o n when t h e necessary equipment can be acquired.
The radiation sensors are mounted an an exposure table some 30 metres north of the instrument van which contains the recording equipment.
T h e n o r m a l i n c i d e n c e pyrheliometer is also being used to determine atmospheric turbidity. The measurement of turbidity is defined for WMO baseline purposes as the r e d u c e d t r a n s p a r e n c y o f t h e atmosphere caused by absorption and scattering of radiation by solid or liquid particles, other than clouds. In a general sense, turbidity would include the reductions caused by molecular scattering, and by the selective absorption by gaseous constituents.
Each of these effects is dependent on frequency; the absorption due to water vapour, which is by far the most significant absorption effect and which is a variable quantity, is almost eliminated by making radiation measurements only at the short-wave end of the visible spectrum. The next most significant effects, molecular scattering and absorption by ozone, are estimated and the short-wave intensity measurement corrected accordingly. Comparison of the corrected short-wave intensity reading with the corresponding intensity outside the atmosphere leads to a figure for turbidity.
These measurements are only made when there is a clear view of the sun and in north-west Tasmania the incidence of cloud limits the number of measurements which can be made.
A preliminary survey shows that in 12 months there were only 16 clear days of which 5 were in the winter months May to August. However, turbidity measurements can be made more frequently since it is only necessary for the sun's disc to be cloud-free for about half an hour to obtain a valid determination of turbidity. The limited results obtained so far have, on
most days, yielded the very low values of turbidity which would expected under "baseline" conditions.
A preliminary analysis of the turbidity data obtained from April to July 1977 shows that, when the wind was in the north-west to south-west sector, the average value of thirty-five readings was 0.019. On the remaining thirty-five occasions, the average value was 0.023. The difference between these two means is just significant, but more data required for reliable conclusions.
PRECIPITATION
Rainfall, a standard meteorological parameter, has a special contribution to make to BAPS studies. Quantative analysis and measurement of its dissolved constituents gives some
information on the gaseous and particulate contents of that part of the atmosphere swept by the raindrops.
To prevent contamination of the precipitation samples the collection device is opened only when rain is falling and when the wind is bringing
"baseline" air over the site. Analysis techniques have been explored by the Tasmanian College of Advanced Education in the years 1975 and 1976, and regular analyses are now carried out by the Australian Government Analytical Laboratories in Hobart.
The potential of this work is not clear. It seems to be a possible source of information about atmospheric constituents which may correlate with direct measurements of gases and particles. It also seems to offer information which might be closely related to climate, particularly the chemistry associated with the initiation of precipitation. So far we have analyses but no program to study them.
RELATED RESEARCH
The permanent baseline station is planned to provide facilities for scientific experiments in a "baseline"
environment. Already the temporary station at Cape Grim has proved to be of value in this respect. Studies have been carried out on the fall-out of lead and other metals (B. N. Noller, University of Tasmania) and on the same elements collected by high volume filtration of the atmosphere, (H. S. Goodman, CSIRO Division of Atmospheric Physics).
Many samples of Cape Grim air have been taken for analysis for site evaluation and comparison with on- site instrument measurements but' recently some interest has been shown in taking larger samples of air collected under baseline conditions for use as a laboratory reference gas.
A four-week visit took place during February by scientists of the Max Planck Institute, Federal Republic of Germany, to sample hydrocarbons, total aerosol which will be analysed for elemental composition, and to sample and analyse rainwater for formaldehyde.
There seems little doubt that the temporary Australian baseline station at Cape Grim, if it is developed as a permanent atmospheric observatory, will not only meet Australia's commitment to the United Nations, but will also fill a valuable role in complementing many Australian and overseas research programs and providing facilities for future research on the atmospheric environment.
The author wishes to acknowledge the many scientists and technicians whose work has provided material for this article.
REFERENCES BRANCH NEWS COMPANY NEWS
1. International Standard ISO—TC 146/SC4 1977-12-12, "Performance Characteristics and Related Concepts for Air Quality Measuring Methods".
2. Pearman, G. I., and Garratt, J. R. "Errors in a t m o s p h e r i c C O2 c o n c e n t r a t i o n measurements arising from the use of reference gas mixtures different in composition "to the sample air". Tellus. 27, 62 (1975).
3. Galbally, I. E. "An Evaluation of the Ehmert Technique for Measuring Ozone Profiles in the Atmospheric Surface Layer."
J. Geophys Research, 74, (28) (1969).
IUAPPA NEWS United States of America
Dr. L. H. Rogers has been appointed Executive Vice President Emeritus, upon his r e t i r e m e n t as Chief Administrative Officer of APCA. He has been succeeded as Executive Vice President by W. G. (Gill) Hamlin, who joined the APCA administrative staff in April 1978, as an Associate Executive Vice President.
Before becoming Executive Vice President of APCA, Dr. Rogers was corporate director of research for Automation Industries, Inc. in Los Angeles, and earlier was senior chemist with the Air Pollution Foundation there. During 1954 to 1958, he supervised contract research, contributing to universal recognition of motor vehicle exhausts as the major cause of photochemical smog in Los Angeles and elsewhere. Dr. Rogers has served as Executive Vice President of APCA, since January 1971.
France
The French Institute of Energy has published an extremely useful list of standards of emission and air quality s t a n d a r d s for t h e p r i n c i p a l industrialised countries. (Limitation des Emission de Polluants et Qualite de L'Air. Valeurs Reglementaire dans les Principaux Pays Industrialises.
Specifications en vigueur en 1978, par Mme P. Jarrault, Ingenieur, Centre de Documentation I.F.C.). Obtainable from: Institut Francais de l'Energie, 3 Rue Henri-Heine — 75016 Paris.
Publication No. 63, July 1978.
South Africa
T h e N A C A a r e h o l d i n g a n International Conference on Air Pollution in Pretoria, S.A., on the 22- 25 October 1979. Details of the call for papers will be given in a later issue of the IUAPPA Newsletter.
New England Sub-branch
The inaugural meeting of the New England Sub-branch of the Society was held in Armidale, N.S.W., on 27 September 1978. Professor Burton is C h a i r m a n of t h e S u b - b r a n c h Committee, and the Secretary is Mr.
W. Pradham. Among others, 13 new.
members of the Society attended. Mr.
S. Stanley, Treasurer of the N.S.W.
Branch, represented the Society, and Mr. J. Sinclair represented the State Pollution Control Commission.
Queensland
The Branch celebrated a successful year of operations by combining the 1978 Annual General Meeting with a Branch Dinner, when 46 members and ladies attended. The A.G.M. was conducted with the usual verve and efficiency, just failing to break the record of 12 minutes 42 seconds.
Following an excellent repast, members were entertained by Dr.
Hugh Lavery, Director, Research and Development, National Parks and Wildlife Service, who took as his subject "The long and short of nature conservation."
Branch Committee for the coming two years will be: Mr. Stewart McFarlane — Branch President, Mr.
B e v a n T h i e l e — B r a n c h Secretary/Treasurer, Mr. Peter Anderson, Mr. Peter Arlidge, Dr.
P a u l G r e e n f i e l d , D r . P e t e r Hetherington, Mr. Phil Kendall, Mr.
Arthur King, Mr. Pat King, Mr. Ted Wziontek.
L o y Y a n g E l e c t r o s t a t i c Precipitators
Lurgi Australia last year won the largest electrostatic precipitator contract ever awarded in Australia. It is for the Loy Yang 'A' brown coal fired power station located in the Victorian Latrobe Valley consisting of 4 x 500 MW units. The total gas volume to be cleaned by this plant is 5500m3/s from which at least 98.9% of the fly ash will be removed by the electrostatic precipitation.
Particular emphasis had to be placed on the removal of grit which required the provision of special mechanical pre-collectors. The first boiler is to be commissioned in November, 1982, with subsequent boilers coming on line in November, 1983, 1984 and 1986. The total contract value is $49.9 million which includes the precipitator mechanical pre-collector and ash disposal plant.
This Loy Yang order is the sixth major electrostatic precipitator contract won by this company since entering the gas cleaning field in 1975.
New Filtration Manual
A new Air Filter Application Manual has recently been released by the Air Handling Products group of Email Limited. It details the parameters for air filter selection in commercial applications. Subjects covered at i n c l u d e the n a t u r e , s i z e a n d concentration of dust, the factors affecting filter p e r f o r m a n c e , a summary of filter testing standards, and details of the various types of filters. The manual then discusses how to select air filtration equipment, followed by a detailed account of an owning and operating cost analysis, enabling cost assessments to be made on varying filter types.
Other areas covered include filter location and limitations, and the necessary precautions associated with air filtration operation. The manual is available from all Email Air Handling offices.
CANADA'S AIR POLLUTION CONTROL PROGRAM
R. M. Robinson
Air Pollution Control Directorate;
Environmental Protection Service, Department of the Environment, Government of Canada.
This was a keynote paper at the International Clean Air Conference Brisbane, May, 1978.
ABSTRACT: The constitutional basis for Canada's air pollution legislation is presented. The Federal Government's role as described under the authority of Canada's Clean Air Act includes the establishment of air q u a l i t y o b j e c t i v e s , r e g u l a t o r y p r o g r a m s , c o - o p e r a t i o n with provincial governments and advisory services. The a p p r o a c h of the Canadian Government to air pollution control stresses containment at source based on best practicable technology.
National emission guidelines are being promulgated for major industry sectors and national emission standards are being prescribed for air contaminants that constitute a significant danger to health. Motor vehicle emissions are regulated at the point of manufacture under the Motor Vehicle Safety Act. A national air pollution surveillance network has been operating since 1970 and is being steadily expanded.
INTRODUCTION
Canada's Clean Air Act was officially proclaimed on November 1, 1971.
This Act provides the basis for the Federal Government's air pollution control activities and has three main elements. First, it reflects recognition by the Federal Government of the primary jurisdictional authority of provincial governments to control air pollution by providing for various ways and means to complement and supplement provincial programs. The second major element of the Act is that it provides federal authority to regulate in those areas where federal jurisdiction is involved. These areas include the control of pollutants which are hazardous to health, the control of pollutants from federal facilities, and the composition of fuels. The delineation of a federal leadership role is the third major element of the Act, enabling the Federal Government to promote uniformity across Canada and prevent pollution havens.
Because air pollution control in Canada is a shared jurisdiction, a Federal-Provincial Committee on Air Pollution including all ten provinces has been constituted as the principal formal mechanism for obtaining Federal-Provincial co-operation and
to ensure participation of all who wish to participate in specific projects. This Federal-Provincial Committee is a working committee of senior officials in air pollution control at the federal and provincial levels of government.
Although chaired by the Federal G o v e r n m e n t , i t p r o v i d e s a consultative mechanism for officials of both levels of government as well as an effective forum for the examination of priorities and programs for a nationwide approach to air pollution control.
The Clean Air Act authorizes the development of ambient air quality objectives based on a three level approach. These objectives are p r e s c r i b e d for " d e s i r a b l e " ,
"acceptable" and "tolerable" ranges for each pollutant. The maximum desirable levels define the long term goal for air quality and provide a basis for an anti-degradation policy for the unpolluted part of the country.They will also provide an incentive for continuing development of control technology. The maximum acceptable levels are intended to p r o v i d e adequate protection against effects on soil, vegetation, water, materials, animals, visibility, personal comfort and well-being. The m a x i m u m tolerable levels denote concentrations of air contaminants that could lead to a substantial threat to public health.
Actions to prevent the development of such a threat should commence at concentrations of air contaminants not exceeding the values given for any pollutant. Objectives at all three levels have been promulgated for sulphur dioxide, total suspended particulate matter, carbon monoxide, ozone and nitrogen dioxide. In 1976 objectives at the desirable and acceptable levels were proposed for hydrogen fluoride and hydrogen sulphide. Existing and proposed air quality objectives are shown in Table 1.
Another project of the Federal- P r o v i n c i a l C o m m i t t e e on A i r Pollution is the National Air Pollution Surveillance Network. This network is a federal-provincial co-operative activity. The provincial agencies, for the most part, operate monitoring stations in the network and report the data to the Federal Government. The
Table 1 Canada's Ambient Air Quaiitv Objectives*
(as of January 19, 1978) (Concentrations in μg/m3)*
*Conditions of 25°C (77°F) and 1033.2 mb (760 mmHg) are used as basis for conversion from μg/m to ppm, pphm, and ppb.
**Proposed.
Federal Government's role varies from the provision of technical advice to the supplying on loan of the instrumentation and assistence with i n s t r u m e n t m a i n t e n a n c e a n d calibration. In some cases, the Federal G o v e r n m e n t may o p e r a t e t h e equipment as well. The federal role depends on the needs and resources of the individual provinces. The network is designed to monitor all locally significant air pollution parameters in all significant centres of population.
As of this date, the network consists of 556 instruments in 157 stations located in 54 cities, and includes m o n i t o r i n g for s o i l i n g index, suspended particulates, lead, dustfall, sulphation rate, sulphur dioxide, hydrocarbons, carbon monoxide, nitrogen dioxide and ozone.
STATIONARY SOURCES
The Federal Department of the Environment has embarked on a program of developing emission guidelines for specific industry sectors.
This thrust is in reponse to the government's philosophy of pollution control which is based on containment at source. The guidelines, while not federally enforceable, are viewed as- the federal requirements for new sources aimed at reducing and/or avoiding further environmental
degradation. The guidelines also serve as goals for existing sources. The government's philosophy on pollution control, while based on containment at source also recognises that local conditions in specific areas of the country may require more stringent c o n t r o l . Guidelines have been published for the following industry sectors:
1. Cement indutry (1974)
2. Asphalt paving industry (1975) 3. Metallurgical coke manufacturing industry (1975)
4. Arctic mining industry (1976) In addition guidelines are presently being developed for the following sectors:
1. Iron and steel 2. Pulp and paper 3. Incinerators 4. Ferrous foundries
5. Natural gas processing plants 6. Petroleum refineries
7. Thermal power plants 8. Non-ferrous smelters 9. Chemical fertilizers
10. Petrochemicals and resins Environment Canada is also in the process of developing national emission regulations for those industries which have emissions that
are considered as constituting a significant danger to human health.
Such regulations are enforceable by the federal government. A national emission regulation for the control of lead emissions from secondary lead smelters has been promulgated and was effective August 1, 1976.
Regulations for mercury emissions from chlor-alkali plants and asbestos emissions from asbestos mining and milling o p e r a t i o n s have been promulgated. The effective date of the mercury regulation is July 1, 1978 and of the asbestos regulation is December 31, 1978. A ministerial announcement of a regulation controlling vinyl chloride emissions from vinyl chloride and polyvinyl chloride plants was made on June 18, 1977. The proposed effective date of this regulation is July 1, 1979. Development continues on regulations to c o n t r o l arsenic e m i s s i o n s from gold r o a s t i n g operations and from non-ferrous smelters. Consideration is being given to the development of regulations controlling emissions of mercury and lead from non-ferrous smelters and arsenic from iron ore processing.
Table 2 outlines the emission requirements under regulations which have been promulgated.
MOBILE SOURCES
The automobile is the most significant source of air pollution in this category.
Emission limits which have been in effect since model year 1975 and will remain unchanged until model year 1981 are:
Carbon monoxide: 25.0 grams per vehicle mile
Hydrocarbons: 2.0 grams per vehicle mile
Nitrogen oxides: 3.1 grams per vehicle mile
Lead-free Gasoline Regulations These regulations, which became effective July 1, 1974 restrict the concentrations of elemental lead and phosphorus to a maximum of 0.06 grams per imperial gallon and 0.005 g r a m s per i m p e r i a l g a l l o n respectively.
Leaded Gasoline Regulations Effective J a n u a r y 1, 1976 the maximum concentration of lead is restricted to 3.5 grams per imperial gallon. The regulations also require the submssion, commencing October
1, 1974, of information on the ammount of lead additive being used by the refining industry and importers and on average lead concentrations in leaded grades of gasoline, during each quarter. This information, together with data on the increased use of lead- free gasoline, will enable the government to ascertain whether the
