Sulfur dioxide and suspended particulate matter

ESVIRONM~.NTL

RESEARCH

Sulfur

11, 287-304

Dioxide

(1976)

and Suspended Where

K. MeLlicoI

Fwrrlty.

Barn Received

Particulate

Matter

Do We Stand?’ BIERSTEKER 170. Rottc~rdrrm. March

Nc~thc~rlrrncls

30. 1974

INTRODUCTION

In 1972, the World Health Organization invited a number of scientists to prepare a document on air quality criteria and guides for the more common urban air pollutants SOS, particulates, carbon monoxide, ozone, and nitrogen oxides. The resulting paper 506 of the Technical Report Series gives expected health effects and recommended long-term goals for four of the mentioned pollutants. The expert committee did not include nitrogen oxides due to lack of sufficient data. Though for some other pollutants the available evidence was sometimes difficult to interpret, agreement was reached for the most relevant criteria and long-term goals. Tables 1 and 2 give the criteria and goals for SO, and particulates. The values in Table I are in round numbers and this was done on purpose, for neither the underlying medical data nor the sampling data warranted further refinement of numbers. As a next step, national governments or larger units like the European Community may become interested in the validity and use of document 506 for air pollution control. In fact, this is one of the purposes for which the report was published. Because air pollution control has important economic consequences, a phased approach is justified. After the objectives have been accepted, a program will have to be developed to ascertain the local pollution levels and to work out short-term and long-term air quality improvement programs. The values of Table 2 imply that in many urban communities in Europe much improvement is still needed if long-term goals are to be met in the not too distant future. To guide us in the right direction, air quality criteria documents are helpful. They do not talk about culprits but about the disadvantages of living in polluted air. We should be glad that the more basic public health needs are more and more frequently met in our society and that there is now time to think not only about the length of life but also about the quality of life (Biersteker, 1972). For those who have a house. a car, enough clothing, and plenty of food and drink, this is a logical next priority. Industry, too, is now convinced that this is the right development in Europe (de la Calle, 1973). 1 This paper was written at the request of C.E.C. to assist the Health Protection Directorate in proposing air quality standards for SO, and particulates for the community. For this purpose new developments since World Health Organization document 506 were screened in the air pollution literature. 287

288

KLAAS

BIERSTEKER

TABLE EXPEC:.I.ED HEAI.TH

Pollutant

EFFKI.S

I

OF AIR POI.LC~ON

Excess mortality and hospital admissions

ON S~I.ECTED

Worsening of patients with pulmonary disease

SO,b

500 pgirn3 (daily average)

500-250 &m3 I’ (daily average)

smokeb

500 &m3 (daily average)

250 &rn” (daily average)

POPULXIXON

Respiratory symptoms 100 pg/m3 (annual arithmetic mean) 100 &m3 (annual arithmetic mean)

GROCPS”

Visibility and/or human annoyance effects 80 &m3 (annual geometric mean) 80 pg/m3 (annual geometric meany

a The Committee specifically urged that this table should not be considered independently of the accompanying text. * British Standard Practice (Minister of Technology, 1966). Values for sulfur dioxides and suspended particulates apply only in conjunction with each other. They may have to be adjusted when translated into terms of results obtained by other procedures. c These values represent the differences of opinion within the Committee. d Based on high-volume samplers.

DIFFICULTIES

IN STANDARD

SETTING

If the ambient air contained only one or two pollutants per place or time, it might be possible to come up with a long list of maximal permissible emission concentrations. After many years we have a growing list of such values for occupational health purposes. Normal workers are considered to run no health risk and not to undergo unbearable nuisances, if these TLVs (threshold limit values) or MAK werte (Maximale Arbeitsplatz Konzentrationen) are not exceeded for workers employed 8 hours per day and 5 days per week. The values (means or absolute ceilings) differ very little in Europe, since they are mostly based on data

Pollutant and measurement method Sulfur oxide&-British

Standard Procedure’

Suspended particulateZ-British Procedure” Carbon monoxide-nondispersive

Standard infrared

Photochemical-oxidant as measured by neutral buffered Kl method expressed as ozone

Limiting level annual mean 98% of observations” below annual mean 98%, of observations’ below 8-hour average 1 hour maximum 8-hour average

200 pg/rn3 40 &m3 120 pg/m3 IO mgIm3 40 mg/m” 60 &m3

l-hour maximum

I30 &m3

60eW

RThe Committee specifically urged that this table should not be considered independently of the accompanying text. b Values for sulfur oxides and suspended particulates apply only in conjunction with one another. ” Methods are not those necessarily recommended but indicate those on which these units have been based. Where other methods are used an appropriate adjustment may be necessary. d The permissible 2% of observations over this limit may not fall on consecutive days.

SULFUR

DIOXIDE

AND

SUSPENDED

PARTICULATE

MATTER

289

published by the American Conference of Governmental Industrial Hygienists. The third edition of their TLV documentation was published in 1971. For a limited number of such pollutants, even international agreement exists in this respect (Truhaut, 1971). The difficulties with ambient air standards are that there are always more than two or three pollutants in the air, that concentrations may vary widely due to uncontrollable meteorological and topographical conditions, and that reactions between the individual pollutants take place in the air, resulting in new pollutants. Such reactions can be stimulated by strong sunshine or high humidity. In Los Angeles, with clean fuels and clean industries, the total emission of particles is low but many gaseous pollutants end as particles (nitrates, sulfates, etc.) as a result of such reactions. In fact, about 35% of the particles there have a gaseous prephase (Friedlandler, 1973). The ratio of sulfates to sulfur oxides seems to increase when we move from east to west in the U. S. A. (Altshuller, 1973). This could mean that the same concentration of SO, is less harmful in different parts of the world, depending on secondary pollutants. In Europe 5- 10% of the sulfur oxides occur as H,SO, on winter days (Benarie et nl., 1973). Acid rains are common now, both in the U. S. A. and Europe (Likens and Bormann, 1974). It is, anyway, an old concept in public health that SO, alone does not explain the observed community reactions on air pollution. Many investigators are still very reluctant to see more in SO, than an indicator pollutant. There is, in fact, more reason to ascribe a harmful effect to smoke at ambient air concentrations than to SOZ, for smoke alone gives, in the long run, rise to the blackening of our lungs and contains a number of carcinogens. Uncontrolled growth of particle emission on the atmosphere also has an effect on weather (rain, temperature) according to meteorologists (Hobbs et (II., 1974). Of course, the first generally known effect of smoke pollution on health was the diminished sunshine and the resulting higher risk for children to develop rickets (Loomis, 1970). Sulfur dixoide begins at 1 ppm to have a lowering effect on nasal mucus flow rate (Andersen et ul., 1974) while 0.75 ppm SO, lowers lung function tests in active healthy young males (Bates and Hazucha, 1974). Effects of chronic exposure to 0.142 ppm pure SO, are hard to find in the experiments, however. In thinking about SO, and particulates, we have to realize that practically all epidemiological data that deal with the pollutants handled them as indicator pollutants joined in their attack on our upper, middle and lower airways by a number of others, for example, zincammoniumsulfate, sulfuric acid, etc. Bates (1972) illustrated possible effects with a few simple diagrams (Fig. 1). Animal experiments (Fig. 2) have, indeed, shown repeatedly that small acid particles are probably essential in explaining the harm that sulfur oxides may cause (Lewis et al., 1972). The acute effects in test animals can be multiplied five fold or more and effects on human lungs have to be explained in a similar way (Amdur, 1970). Even so, the ill-defined combination of SO, and smoke is, for lack of better, used by public health officials as an index of reducing urban pollution. WHO’s report 506 states clearly that it talks of urban pollutants. All interactions and

290

KLAAS

BIERSTEKER

FIG. 1. (A) Effect of irritants in major bronchi; (B) effects of irritants in terminal bronchioles; effect of irritants in alveoli.

(C)

reactions (physically, chemically, and biologically) should therefore be covered by its criteria table (Table 1) and the long-term goals. These long-term goals were tentatively set at what might be called zero effect levels. The levels at which effects have to expected according to at present available evidence or criteria were given in Table 1.

SULFUR

I 0 02

71 0 01

DIOXIDE

I 0.05

AND

SUSPENDED

I 0.1

I 0.2

SULFUR

0.01

EQUIVALENTS.

PARTICULATE

I

0.5

I

10

I

I

2.0

50

10

mg/d

10

01 SULFUR

291

MATTER

DIOXIDE.wn

FIG. 2. Comparison of irritant potency of sulfur dioxide and sulfur-containing beside each point indicate number of animals. Data from Amdur.

particulates. Numerals

Time will show us how good the safety factor between Tables 1 and 2 is. WHO and the C.E.C. are conducting studies at present on populations of schoolchildren to discover the effect of combinations of high SO, plus low smoke, high smoke, and low SOP, etc. In the U. S. A., the CHESS program is doing the same. A recent air pollution episode in Birmingham and New York City showed that even with very low SO, concentrations acute health effects may be observed in urban communities (Nelson et ul., 1973). RECENT DATA GROWTH

If we list some of the recent developments observations seem relevant.

in individual

countries,

the following

Japan Japan has gradually acquired the reputation of being possibly the most industrious but also the most polluted nation of modern times, the first one with specific pollution diseases. Reports of the unfortunate methylmercury and cadmium intoxications and the accidents with arsenic and PCBs have been circulating all over the world. The terms Tokyo-Yokohama asthma and Yokkaichi asthma are less well known, but I understand that hundreds of Japanese with CNSLD now claim financial compensation for their respiratory ailments (Syrota, 1973). Health effect studies. In Osaka, the prevalence of chronic bronchitis in adults showed a linear relationship with the sulfation rate (Fig. 3). A linear relationship existed both in males and females, though for females at a lower level, as a result of less cigarette smoking by Japanese women. Compared with a control population, the prevalence may be three times higher as a result of pollution. The authors (Tsunetoshi et al., 1971) point out that the Nishitodagawa district experiences heavy industrial pollution and high sulfuric acid concentrations.

292

KLAAS

BIERSTEKER

FIG. 3. Prevalence of chronic bronchitis and sulfur dioxide by PbO, method in Osaka.

According to the report published by the Japanese Expert Committee that proposed SO, standards for Japan, the following effects have been observed in Japan. (1) Mortality increases in Osaka on days with 300 wg S0,/m3 and more (24 hour value). (2) The incidence of respiratory infections doubles in Yokkaichi on days with 300 kg S0,/m3 (24 hour value). (3) In districts with more than 150 pg S0,/m3 (long-term average) the number of bronchitics is about twice as high as normal. Alert levels. Some refineries emitting large quantities of sulfur oxides now have to pay millions of yens to bronchitics for medical treatment claims. Even so, the adopted alert levels are very tolerant compared with the values given in the U. S. A., in the U. S. S. R., Japan itself (Table 3), and by WHO as air quality goals. In the Rotterdam area we face the same problem: Should we set our emergency levels on the basis of the effects that began to occur in London with daily averages of 500 pg S0,/m3 and 250 pg smoke/m3? Or are we suddenly tolerating a certain amount of discomfort among the sick and infirm and are we setting our alerts for people in a fairly normal condition? I think we should be consistent and protect medically the weakest members of the group. Srandurds. See Table 4. Benelux Air pollution

with a limited

alerts. The Japanese situation is maybe indicative of what we get number of chimneys with high sulfur oxides emissions. In that case,

SULFUR

DIOXIDE

AND

AI.WI~ Warning Pollutant Sulfur

(ppm)

oxides

Suspended

TABLE Lrver.s

PARTICULATE

3 IN

JAPAW~

of alarm (hours)

2.0 mgim”

293

MATTER

Serious

2

” Modified from Environmental Agency, Japan, 1973. *Measurement methods: Sulfur oxides-sulfur oxides method; Particulates-suspended particulates concentration

emergency (hours)

(ppm)

3 2 I 48 average

0.2 0.3 0.5 0.15 particulates

SUSPENDED

monitor monitor

0.5 0.7

3 2

3.0 mg/m”

3

using conductometric using the light scattering

analysis method.

especially during fumigations, the short peak concentrations can become very high, though the averages will remain below the levels that are medically alarming. If we want to prevent this, industry will have to be warned sufficiently in advance. Clarenburg tried to use SOP, therefore, as a meteorological predictor in Rijnmond (Brouwer, De Veer and Zeedijk 1971). If the A value 3 - 1, indicating the rise in pollution level, is larger than zero, and if this occurs at a sufficiently large number of sampling stations in the Rotterdam industrial area, industry is alerted. It is hoped by gradually combining the right moment of issuing alerts and the right steps to be taken by industry, that excessive emissions of sulfur oxides, malodors, and other pollutants can be prevented. The hope exists that 350 pg SOS/m3 can be avoided in this way (Syrota, 1974). Particulatr anulysis. Demuynck and Dams (1974) showed that in Belgium suspended particulates can stay long enough in the air to be measurable at a distance

MAIN

So,

so,

USA 1974

AN”

PAHIlCI’LAl

PRt.St

Xl 1.Y IS

USE

particulates

75 F&m3

(mean, year). 365 @g/m” (highest day in year) (3 hour maximum. secondary standard to protect plant damage) (median, year). 260 &m3 (highest day in year)

USSR I973

so, smoke

50 &m3 50 pg/m3

(24 hrs). (24 hrs).

Sweden 1965

so,

Netherlands 1970 proposed

so, smoke

West 1974

so2 particulates

140 &m3 100 pg/m”

(24 hrs), 400 &m” (24 hrs). 200 fig/m”

(30 minutes) (30 minutes)

so, particulates

120 &m” 100 &m3

(24 hrs). 300 &m” (24 hrs), 200 &m”

(I hr) (I hr)

Japan I973

Germany

80 &m3 1300 &m3

TABLE 4 tS S.IANI)ARI)S

150 fig/m” 750 PgIm” 75 &m3 30 &m3

500 &m3 150 fig/m3

(highest month). (30 minutes) (median, (median.

year). year),

against

(20 minutes) (20 minutes)

300 pg/m”

(highest

day in a month).

250 kg/m” (98 percentile) 90 pg/mS (98 percentile)

294

KLAAS

BIERSTEKER

of 100 and more kilometers from the source. They used high volume samplers and neutron activation analysis to trace the sources. Compared with smoke measurements the method is far more refined. It is hard to compare the results of smoke measurements (based on blackness of urban particulates) and such data, but we will no doubt move into more refined particulate analysis (and standard setting) in coming years. Health eifect studies. A number of air pollution health effect studies were published in Holland (Biersteker, 1972). The main conclusions were as follows. On smog days with 1500 pg S0,/m3 in combination with 500 pg standard smoke/ m3, indications of increased mortality and morbidity were found in the Rotterdam area. Asthmatic schoolchildren showed a drop in lung function after playing in ambient air with 800 pg S0,/m3 and 300 pg TSP/m3. Lung cancer and bronchitis and emphysema show an urban gradient which has increased after World War II and shows no signs of leveling off yet. Schoolchildren may offer the best possibility to study health effects, because they do not smoke and have, as yet, no professional exposure to air pollutants, The indoor air pollution is a neglected field of investigation. In Rotterdam, we now try to show an effect of improving air quality in the Westland district, where greenhouses are switching over from heavy oil to natural gas heating. The Westland was divided for this purpose into clean and polluted. If we find effects now we hope that these will disappear with the further progress towards clean air in the area. The study utilizes standard forms that were developed with the aid of the regional WHO office in Copenhagen. Comparable data collection started this year in a number of other countries, e.g., Poland, Denmark, Rumania (Arhirii et al., 1974). In these studies, low level pollution is defined as median annual concentration less than 5Okg S0,/m3 plus less than 30 pg standard smoke/m3. High level pollution is defined as more than 100 kg SOP/m3 and 40 pg smoke/m3. Stundards. There are no official standards yet for SO, and particulates in Benelux, though 75 yg S0,/m3 (annual median concentration) was proposed by the National Health Council of the Netherlands as the national long-term goal (Table 4). West Germany The VDI in West Germany already came in 1961 with a MIK Werte proposal for SO,. This was just after Lawther had published his results with daily notes of bronchitics about their discomfort. Lawther concluded that 600 pg S0,/m3 in combination with 300 pg smoke/m3 was apparently too much for his bronchitics. The choice by VDI of 500 F*glm3 as a ceiling, not to be exceeded during more than 30 minutes in a period of 2 hours, was therefore understandable. How this guide could be made operational in the sense of a 50 and 98 percentile is not clear, but was not, at that time, under discussion. Data about chronic exposure effects were almost completely lacking at that time and played no role in the standard setting. Health effect studies. Air pollution health effect studies in the B.R.D. were undertaken in Duisburg, in Oberhausen, in Gelsenkirchen, and in Frankfurt. Reichel and Ulmer (1970) found indications of a worsening of lung function tests

SULFUR

DIOXIDE

AND

SUSPENDED

PARTICULATE

MATTER

295

and a definite increase of percentage of bronchitis symptoms in the winter seasons in Duisburg as a possible effect of weather, air pollution, and infections. They were unable to find a more permanent difference between their urban population and a control population. When we look at the SO, concentrations that prevailed at the time their data were collected, in 1965, we find only small differences between the urban population and its control. The main difference seems to have been in the dustfall. The SO, levels were over 200 pg/m3 in the control zone. Faerber and Grosze-Heitmeyer (1972) tried to connect the loss of uv radiation in Oberhausen with rickets’ prevalence in babies. Only the percentage of babies with advanced forms of rickets was higher in Oberhausen than in Rees, their control area. The difference in uv radiation between the two areas was 16%. The study used only children in their first year of life. It would have been interesting to have had older children incorporated in the study to see if they also differed. Schlipkoter et al. worked in cooperation with scientists from Prague (1973). They were looking for subtle differences in growth, including skeletal maturation, blood composition, lymph-gland reaction, etc., between Gelsenkirchen and a number of control areas, including the recreation island of Sylt. They found indeed a higher percentage of children with enlarged tonsils and retarded skeletal maturation in Gelsenkirchen. They found also small changes in the erythrograms, which they consider a possible effect of air pollution because it can be reproduced experimentally in animals. As for the acute effects Meier-Sydow et al. (1968) found that in Frankfurt in 1967 the condition of 12 out of 26 patients with chronic nonspecific lung disease (CNSLD) worsened on days with elevated pollution. Their patients kept little notebooks, like Lawther’s bronchitics, and lung function tests were made weekly. Emmerich et al. (1972) analyzed croup syndrome admissions in the years 1967-1971 to the University Clinic in Frankfurt. A total of 576 children were admitted. On days with more than 240 pg/m3 SO., there was a definite increase in admissions. There were, though late, also indications that the 1962 worldwide air pollution episode had caused mortality increase in the Ruhr which did not occur in several surrounding areas (Steiger and Brockhaus, 1971). Summarizing, we may conclude that it has been possible to provide convincing proof that acute air pollution had a negative effect on persons with sensitive airways in West Germany. The effect of chronic pollution was hard to prove, partly because it is a nonspecific effect. Control populations should only differ in respect to air pollution, and this requirement is difficult to fulfill. Prinz (1973) once again stressed this point at the recent IUAPPA meeting in Dusseldorf. As air pollution is rapidly declining in many polluted zones in West Germany, follow-up studies may still show effects to have existed however. Nell, stanhrds crnd alert let-els. In the new Technische Anleitung (TAL) that replaced in 1974 the former technical directive of 1964, the SO, standard has been lowered to 140 pg/m3 and 400 /*g/m” for long- and short-term exposures in Germany (Table 4). The smog alarm system in the Ruhr which first issued its first warning when the SO, level reached 2000 pg/m3, was altered too. Now the first warning is issued at 1000 pg/m3 [Schriftenreihe der Landesanstalt Nordrhein Westfalen 29 (1973) 93.

296

KLAAS BIERS'I‘EKER

England

The largest amount of data about air pollution health effects were generated in the past by British research workers. The work of investigators like Lawther, Martin, Reid, Holland, Lunn, Colley, and Waller helped us gain a much better understanding of the epidemiological requirements in air pollution studies. As sulfur oxides and particulates have, according to our latest knowledge, no specific long term effects, except the gradual blackening of our lungs with the progress of years, the causality of a correlation between pulmonary effects and air pollution is always open to doubt. The most convincing evidence of a possible causal relationship is the change in effect that follows change in exposure. In London and in Sheffield, data have now been produced which can be considered strong evidence for a causal relationship, in connection with acute as well as chronic effects. Health ef$vt studies. Figures 4 and 5 show the dramatic change in air pollution in London. At present, days with more than 500 pg S0,/m3 and more than 250 Fg smoke/m3 are so rare in the winter season that the line of pollution and the line of deviation in morbidity look like unconnected random background oscillations. This means that there is now (1974) little proof that acute air pollution episodes still occur. However, as I pointed out earlier, it may well be true that the full story of acute and subacute health effects has not been documented yet, because of the photochemical reactions that now are beginning to be observed in “clean” British air, too. The disappearance of chronic effects manifested itself in Sheffield during a follow-up by Lunn et a/. (1970) of schoolchildren. The decrease in measured pollution went parallel with a decrease in prevalence rates of bronchitis symptoms. Howard (1974) reported also that in Sheffield the character of the course of bronchitis in adults changed in the period 1966- 1972, probably as a

01 ,959

FIG. 4.

Daily

I

15 OCT

changes

I

in the

15 NO”

condition

I

15 DEC

of bronchitic

I

15 JAN

patients

I

15 FEB

in relation

I

15 MAR

to pollution,

I I960

1959-

1960.

SULFUR

FIG:. 5. Daily

changes

DIOXIDE

in the

condition

AND

SUSPENDED

of bronchitic

PARTICULATE

patients

in relation

297

MATTER

to pollution,

1969-

1970.

result of the substantial fall in air pollution in the city. Waller (1971) observed a decrease in bronchitis mortality in London, a trend that did not exist in the rural areas of England. Lawther et ctl. (1974) found in the same period a slight improvement in lung function tests during a long series of observation on a small group of volunteers. They mention the decline in London’s pollution as a possible explanation for this unexpected trend. Lawther et cl/. (1974) also found, using regression analysis on a series of pulmonary function data, a significant effect of SO, on pulmonary airway resistance in a test person who walked each morning 2.8 km through London to get exposed to the prevailing pollution. The correlation existed between the airway resistance and S02, smoke, and particulate acid, with SO, showing the highest correlation. Parallel with reductions in pollution, the increase in lung cancer mortality has in younger age groups been declining in London (Waller, 1971). Higgins (1974) also reports a slightly greater decline in the mortality from lung cancer in London than in the rest of England and Wales. The possibility exists, however, that there is a cohort effect of pollution, older people never reverting to full pulmonary health after having been exposed in their youth to too much air pollution (Stuart Harris, 1971). In that case the real effect of the improvements will only show up after a much longer period of waiting. Colley et al. (1973) followed in this connection the cohort of children that had been studied by Douglas and Waller to see whether at the age of 20 there still were air pollution effects. They found that cigarette smoking and a history of respiratory illness under 2 years of age were the main determinants of symptom prevalence at 20. Waller et al. (1974) compared a group of children born before and after the smog incident in December 1952, when they reached age 18. There was no indica-

298

KLAAS

BIERS'I‘EKER

tion of a permanent effect on pulmonary health from having been exposed to this smog. Comment. All these optimistic notes from the United Kingdom should not conceal the fact that the U. K. moved from a fairly unfavorable situation to a situation which is common in many European communities. There may, in other words, be an indication of a zero-effect level for acute pollution in these data, but we still remain uncertain about the chronic effects. Standards. There are no official standards in England. Sweden was in 1965 one of the first countries to adopt a SO, standard (see Table 4). Recently a Swedish Air Quality Criteria committee went over the newest data, including Document 506 of WHO: Air Quality Criteria and Guides for Urban Air Pollutants. The committee concluded that values in Table 2, the long-term goals recommended by WHO for SO, and suspended particulates, should be used in planning air pollution control in Sweden. A question remained whether annual or semiannual concentrations should be studied. The committee felt that, at least in Sweden with higher population in the winter months, the long-term goals should specifically be applied to the winter months (Air Quality Criteria and Guides for Sweden in Regard to SO, and Suspended Particulates. Stockholm, 1973). U. S. A.

The Environmental Protection Agency initiated a few years ago a new program, called CHESS (Community Health and Environmental Surveillance System). It tries to evaluate the federal air quality standards which were first proposed in 1970 and amended in 1973 (Table 5). A large amount of data is forthcoming from these studies that were conducted in Salt Lake City, New York, Chicago, and other locations. in areas with dominantly SO, pollution, dominantly particulate pollution, and in areas with combinations of both. Some of the results were hrst presented at the AMA Air Pollution Medical Research Conference in Chicago in October 1972. Standard testing. The CHESS studies in the U. S. indicate (Love, 1974) that both acute and chronic health effects are associated with exposure to ambient air containing approximately 100 Fg/m3 S02, 100 pg/m3 suspended particulates and 15 &m3 sulfates. The levels of sulfates were associated more closely than the other pollutants with the effects. The overall conclusions of EPA. looking at all the CHESS data, are that the standards at present used in the U. S. have not been set too high, for there are indications that health effects occur at very low levels of S02, possibly due to the so far neglected role of sulfates and sulfuric acid in triggering responses. Other datu. French et ul. (1973) reported croup or laryngotracheobronchitis as the major condition productive of excess acute respiratory disease in children in polluted communities surveyed by the CHESS program. According to Lave and Seskin (1972), mortality in American cities increases per micrograms per cubic meter of sulfate with 70 per million, per microgram per cubic

SULFUR

DIOXIDE

.4ND

SUSPENDED

PARTICULATE

TABLE U.S.A. Pollutant

PRIMARY

AND

Type of standard

Carbon monoxide

Primary and secondary

Hydrocarbon (nonmethane)

Primary and secondary

Nitrogen dioxide

Primary and secondary

Photochemical oxidants

Primary and secondary

Particulate matter

Primary Secondary

Sulfur dioxide

Primary Secondary

SECOSDARI

5

AMBIEXI-

Averaging time 1 hr 8 hr 3 hr (6 to 9 AM)

299

MATTER

AIR

QVALITY

SLAND.~RDS

Frequency parameter Annual maximum” Annual maximum

Concentration (w&f? (wm) 40,000 10,000

35 9

Annual maximum

l6ob

0.24b

1 yr

Arithmetic

mean

100

0.05

1 hr

Annual maximum

100

0.08

Annual Annual Annual Annual

260 75 150 60“

-

24 24 24 24

hr hr hr hr

24 hr 1 yr 3 hr

maximum geometric mean maximum geometric mean

Annual maximum Arithmetic mean Annual maximum

365 80 1300

0.14 0.03 0.5

n Not to be exceeded more than once per year. b As a guide to devising implementation plans for achieving oxidant standards. ” As a guide to be used in assessing implementation plans for achieving the annual maximum 24-hour standard.

meter of particulates with 4 per million. A SO% reduction in air pollution would result in an increase in life expectancy of about 1 year for a new-born. Buechley ef rrl. (1973) concluded that on days with more than 300 lg S0,/m3 in New York, mortality increases with 1 to 2%. Though these increases are small, they can occur frequently enough in communities to raise the total number of deaths considerably. Carnow and Meier (1973) concluded that in the U. S. an increase of 1 pg 3,4 benzpyrene/lOOO m3 of urban air results in a 5% increase in lung cancer mortality. Comment. There seems to exist an instinctive fear in the U. S. that air pollution in any visible or malodorous form is a bad sign, as there may be other risks sooner or later in the air too. The public in the U. S. A. simply wants the air to be as clean as possible according to Sussman (1971) and shows little interest in the principles of air resource management and air quality criteria. The public wants, in other words, primary emission or source control to be applied more effectively. The results of these studies tend, in general, to support the chosen standards for SO, and particulates (Table 4). There are in fact indications that health effects occur at still lower levels of pollution, possibly as a result of inhaled sulfates or sulfuric acid. This bring us back to the old question, is a SO, standard sufficient for health protection, or should there be a combined particulate and SO, standard? And (an important question) is a particulate standard without specification of components good enough to protect our health?

300

KLAAS

BIERSTEKER

U. S. S. R.

In the U. S. S. R., air quality standards have been part of the approach to air pollution control since 1949. A special committee was responsible from the start for collecting the scientific data necessary to arrive at standards. In 1951 the first ten standards were published. The criteria used were very strict. A concentration is not allowed to have any direct or indirect harmful unpleasant effect upon man, must not impair his working capacity, and must not have a detrimental influence on his feeling of physical well-being or on his mood. Becoming accustomed to a pollutant is never proof that the concentration is permissible. Concentrations that have a detrimental effect on vegetation, local climate, the transparency of the air, living conditions are not acceptable (Bustueva 1970; Izmerov 1974). In establishing zero effect levels, Russian scientists frequently study the central nervous system for changes in dark adaptation, conditioned reflexes, etc. The standard is set with a safety factor of 30% below the lowest zero effect level. Joosting and Zielhuis (1962) used the title “Pragmatism or Dogmatism?” for a paper in which they compared the familiar epidemiological-toxicological approach in the West and this new one. At that time, there was doubt about the relevance of the data collected by the Russians on dark adaptation, optical chronaxy, etc. Today, with the renaissance in ecological thinking, their approach seems more defensible. The goal in environmental health is to establish optimal conditions for the evolution and enjoyment of society. In that context, the present U. S. S. R. SO, standards of 500 pg Sop/m3 as short-term limit and 50 pg S0,/m3 as 24 hour average are goals which do not look too strange in comparison with other standards (Table 4). The smoke standard stands as 24 hour average at 50 PgIrn”, the only criteria used in the U. S. S. R. being the reduction in sunshine which reaches approximately 10% at this level of pollution. The standard for inert suspended particulates is three times higher. New data for a revision of these standards seem to be looked for by Gildenskjold (1972). It is interesting to know that the U. S. S. R. now has over 100 maximal permissible concentrations for pollutants of the outdoor air. (Bustueva, 1973). Permissible emissions are calculated from the standards with the formula MPE (g/set) = MPC. Hz v.t. / A.F.M. In this formula. A depends on local topographical and meteorological conditions. This means that in the U. S. S. R. emission standards are flexible. From a public health point of view this is more acceptable than proposing different air quality standards for people in different parts of a country. The sampling of the emission concentrations is carried out in the U. S. S. R. with mobile laboratories. Samples are taken downwind of industrial emission sources at a distance of lo-40 times the chimney height during 20 minutes. The responsibility for air pollution control is in the hands of sanitary physicians who receive a 6-year training in medicine and environmental hygiene. There are no less than 5000 of such hygiene units in charge of the protection of the environment at the moment. Other Data

Bates and Hazucha (1974) tried to simulate the new kind of urban pollution exposing young healthy men, who were exercising on a bicycle ergometer

by to

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increase their pulmonary ventilation, to a mixture of SO, and ozone of 0.37 ppm each. There were very significant decreases in mid-expiratory flow rates. Even 0.75 ppm SO, alone was able to reduce under this light exercise lung function tests slightly. Whether the combined effect was due to the formation of fine sulfuric acid aerosol in the gas chamber or airways is not known. Though the concentrations used are fairly high for the outdoor environment of most communities, the investigators are closer than any previous ones to demonstrating experimentally effects that may take place in our cities with photochemical smog. Bates (1972) pointed out earlier that our tools to detect minor changes in lung function are rather crude (FEV only reacts after important damage has occurred in the form of bronchitis or emphysema). Bouhuys er al. (1970) defend the use of mid-expiratory flow rates as more sensitive indicators of early effects. In reality, the number of studies now available using such methods is very limited. This means that the effects described by the old methods may well have underestimated the real harm done by air pollutants on higher, middle, and lower airways. The acidity of rainwater in the northeastern United States has increased in the last 20 years. One theory is that the better smoke control has, in fact, promoted the formation of acid rain. Ecological effects on lakes and soil and forests are still poorly understood due to a lack of data, but increases in acidity in some lakes are enormous, as in Scandinavia. The huge SO, emissions lead to a growing danger in this respect (Likens and Normann, 1974). CONCLUSIONS

The National Health Council of the Netherlands was asked in March, 1967 to advise what levels of SO, in the ambient air should be considered acceptable from the viewpoint of health protection. It took more than 3 years to come up with a recommendation. The recommendation is given in Table 4. There is no mention of the way SO, is to be measured. The recommendation is, in fact, a goal and assumes that the smoke is low too, less than 30 &m3 (annual median). As a SO, committee, the council did not propose different goals for areas with different socioeconomic character. It felt that all people have fundamentally the same right to clean air, though some may get it earlier and others later, due to secondary political considerations. The report states that there is a safety factor 2 incorporated in the choice of the SO, concentrations. These are given as median (50 percentile) and 98 percentile concentrations, as this is the easiest way to plot the standard on graph paper for comparisons with actual frequency distributions of SO, and smoke in a community (Brasser, 1972). In the past, the level of urban air pollution was delineated no doubt by the smoke and SO, levels. Polluted air can never be healthy and if it is doing damage to our upper or lower airways, sulfur oxides plus particulates are more damaging than either of them on their own. We can think of a few specific effects of particulates (smoke) alone, for example the tumorogenic effect due to presence of certain polycyclic aromatic hydrocarbons, but we can think of little effect of pure SO, in the concentrations that prevail in our cities on our lungs. The argument that SO, is so innocent in pure state can never be used to set a permissive standard for the ambient air, however, for ambient air is never without particulates. Owen, the

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father of automated air sampling equipment, discovered already that even over the ocean the air contains impurities. The successful reduction of smoke in our cities, in fact, creates probably new problems (Atkins, Cox, and Eggleton, 1972) because of the photochemical formation of sulfuric acid, a sulfur oxide that is far more dangerous than SO, according to all available toxicological data. Test persons were however not inhaling this smog. In our cities it may well be that the eyes do not hurt like they do in Los Angeles on summer days with smog, but that the throat and lungs react first because of the sulfuric acid when sulfur oxides go uncontrolled. Compared with the past, the context of the fear for sulfur oxides may change, but the need for low sulfur oxides may well increase with the growth of the photochemical smog problem in Europe. SUMMARY

Summarizing the more recent literature findings to reach a conclusion about the validity of the WHO long-term goals, there is little data on which a change of the goals or the criteria can be based. By taking a safety factor, the WHO goals are still somewhere in the no effect level, even though the tendency in the newer research data is to find effects at lower levels than ever before. This may be due to the fact that SO, and particulates can only act as indicators, not explaining the real mechanism underlying the dose effect relationships, for instance through the presence of secondary pollutants like sulfates and sulfuric acid, or even through as yet unrecognized other mechanisms. This can not be used against the standard setting for SO, and particulates, however, until a new mechanism is fully documented. REFERENCES Advies inzake grenswaarden SO, (1971). Verslagen en mededelingen volksgezondheid 1971, No. 22. World Health Organization (1972). Air quality criteria and guides for urban air pollutants. Geneva. 1972, W.H.O. Technical Report No. 506. Altshuller. A. P. (1973). Atmospheric sulfur dioxide and sulfate. E,(r,. Scirncr Techno/.. 7, 709. Amdur, M. 0. (1970) The impact of air pollutants on physiologic responses of the respiratory tract. Proc. Amer. Philosoph. .SCK~. 14, 3. Andersen, I.. Lindquist. G. R., Jensen, P. L., and Proctor, D. F. (1974). Human response to controlled levels of SO,. Arch. Em’. Hectlth 28, 31-39. Arhirii. M. (1974). Study of long-term effects on health of air pollution. Int. Symp. Enr. Heulrh. Prrris. 1974. Atkins. D. H. F.. Cox, R. A., and Eggleton, A. E. J. (1972). Photochemical ozone and sulphuric acid aerosol formation in the atmosphere over southern England. Nature fLondon) 235, 372-376. Bates, D. V. (1974). The effects of low levels of SO, and ozone in the same atmosphere on human pulmonary function. Intern. Svmp. Env. Health. Paris, 1974. Bates. D. V. (1972). Air pollutants and the human lung. Amer. RcL,. Rrsp. Disrtrse 105, I- 13. Benarie, M., Menard, T.. and Nonat, A. (1973). Etude de la transformation de SO2 et HSO,. Atmospheric Env. 7, 403-424. Biersteker, K. (1972). Air pollution Control in the Netherlands. Tijdschr. SM. Genresk, 50, 17-21. Bouhuys, A. et crl. (1970). Pulmonary function measurements in epidemiological studies. Bu/[. Plysioputhol. Resp. 6, 561-578. Brasser, L. J. (1972). Presentatie van meetuitkomsten van luchtverontreinigingsconcentraties in verband met normen voor de beperking daarvan. De Ingenieur 84, G 7-G 15. Brouwer, H. J.. De Veer, S. M., and Zeedijk. H. (1971). Het meetnet voor SO, concentraties in het Rijnmondgebied. Philips Trchn. Tijdschr. 32, 29-37.

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Buechly, R. W., Riggan. W. B., Hasselblad. V.. and Van Brugen, J. B. (1973). SO, levels and perturbations in mortality. Awh. En\,. Hccllfh 27, 134- 137. Bustueva. K. A. (1970). Crrtrrirt u.spec~r,s ofthr strr7ittrr\ protection ofthe uir in the I/. S. S. R. Paper at W.H.O. regional meeting on trends and development in air pollution control. Copenhagen. Bustueva. K. A. (1972). Air qut~lity .sttrndnrtl.s ,fiw cvttritz crttmuphrrk po1lutrrt~t.s in tl7r U. S. S. R. Paper at W.H.O. meeting on Air quality criteria and guides for urban pollutants. Geneva. de la Calle. P. (1973). Criteria and standards. Qrrrrlify (Bulletin of Shell Committee for Environmental Conservation) No. 17. Camow. B.. and Meier, P. (1973). Air pollution and pulmonary cancer. Arch. En)*. Hctrlth 27, 207-218. Colley. J. R. T., Douglas, J. W. B.. and Reid, D. D. (1973). Respiratory disease in young adults: Influence of early childhood lower respiratory tract illness, social class. air pollution and smoking. Brit. i2Zed. Jorrrrrd. II, 195- 198. Corn. M. (1973). London revisited. J.A.P.C.A. 23, 568-569. Demuynck. M., and Dams. R. (1974). Luchtverontreiniging door aerosolen. trtrrn 3. 31 I-342. Emmerich. H.. Bender. S. W., Jaklin. R. H.. et N/. (1972). The effect of atmospheric SO, on croup syndrome. Computer analysis. Z. E;indrrhri/~. 113. II I- 121. Faerber. K. P., and Grosse Heitmeyer. 1. (1972). Rachitisentstehung und Luftverunreinigungen. Oc+ .fhnrl. G~~.sttnd/7ritsu,c~sr~7 34, 5 19. French. J. G.. Lowrimore. G.. Nelson, W. C., Finkler. J. F., English. T.. and Hertz. M. (1973). The effect of SO, and suspended sulfates on acute respiratory disease. Arc,/]. &II.. Hccrltl7 27, 1299 133. Friedlander. S. K. (1973). Relating particulate pollution to sources: Case of Los Angeles aerosol. Pn~c~. fnt. C/c,rrn Air Cort,gr. Dusseldorf. C 78-C 80. Gildenskjold. R. S. (1972). Horizontal chamber for chronic poisoning of animals with finally dispersed dust gases. GiXientr i Strr7itariya 3713). 79-83. Higgins. I. T. (1974). Trends in respiratory cancer mortality in the U. S. and England and Wales. Arch. En\,. Hetrlth 28, 121 ~ 129. Hobbs. P. V., Harrison. H., and Robinson, E. ( 1974). Atmospheric effects of pollutants. Science 183, 909-91s. Howard. P. (1974). The changing face of chronic bronchitis with airways obstruction, &jr, .wrc;. ], 89-93. Izmerov. N. F. (1974). Principles underlying the establishment of air quality standards in the U. S. S. R. W. H.O. Chronicle 28, 255-260. Joosting. P. E.. and R. L. Zielhuis (1962). Pragmatisme of dogmatisme? Tijdsc;z. sot. G~~;~P~X. 40, 479-485. Lave. L. B.. and Seskin. E. P. (1972) Air pollution. climate and home heating; their effects on U. S. mortality rates. Amcr. J. Pith. Hccitlh 62, 909-916. Lawther, P. J., and J. A. Bonnell (1970). Some recent trends in pollution and health in London-and some current thoughts. Proc. Itit. Ckcrn Air Conpr. WL;,rh;;;aton. D. C. Lawther. P. J., Brooks, A. G. F.. Lord. P. W., and Wailer, E. R. (1974). Day to day changes in ventilatory function in relation to the environment ,571~. Res. 7, 27-53. Lawther. P. J., Lord. P. W.. and Brooks. A. G. (1974). Air pollution and pulmonary airway resistance; a pilot study. Env. Rr.v. 7, 424-435. Lebowitz. M. D.. Toyana, T.. and McCarron, J. (1973). The relationship between air pollution and weather as stimuli and daily mortality as responses in Tokyo, Japan, with comparisons with other cities. Ent,. Rrs. 6. 327-333. Lewis. T. R.. Amdur. M. 0.. Fritzhand, M. D., and Campbell. K. I. (1972). Toxicology of atmospheric sulfur dioxide decay products, E,7t,. Protec~tion ,4ge~~~y, I/. S. A., pub]. A.P. ] ] ] Likens. G. E., and Bormann. F. H. (1974). Acid rain: a serious regional environmental problem, S~~ienc.~ 184, I 176- 1179. Loomis, W. F. (1970). Rickets, Scientjfic, Amcrictttz 223 (6), 77-91. Love. G. J. (1974). Epidemiologic studies of adverse health effects associated with exposure to air pollution. Int. Syw7p. EtzL,iron. Hec~lth. Puris. Lunn, J. F., Knowelden. J., and Roe, J. W. (1970). Patterns of respiratory illness in Sheffield junior schoolchildren. a follow-up study. Brit. J. Pwrl. Sot. Med. 24, 223-228.

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Meier-Sydow, J., Beck, W.. Ehrenforth. H., Gonsior, E., Pittrich, W., and Schneider, G. (1968). Ueber den Zusammenhang von Lungenfunktionsstorung. klinischem Schweregrad. Wetter und Luftverunreinigung (SO, Konzentration) bei obstructiver Bronchitis. Blrndes,~r,surldl2ritshlntt 11, 355-362. Nelson, C. J.. Shy, L. M.. English, T., Sharp, L. R.. Andleman. R.. Truppi, L.. and Van Bruggen. 1. (1973). Family survey of irritation symptoms during acute air pollution exposures. J.A.P.C.A. 23, 81-86. Prinz, B. (1973). Planung und Auswertung epidemiologischer Untersuchungen uber den Einfluss von Luftverunreinigungen auf Mortalitat und Morbiditat Proc. Third In/. C/<~un Air Congr., Diisseldorf.

Reichel, G., Ulmer, W. T., Gary, K. et al. (1970). Einfluss des ortlich unterschiedlichen Verschmutzungsgrades im Stadtgebiet von Duisburg auf die Haufigkeit Atemwegserkrankungen. Intern. Arch, Arbeitsmed. 27, 110-129. Reichel, G., and Ulmer, W. T. (1970). Einfluss des Jahreszeitlichen Wechsels der Luftverunreinigung und der Wetterfaktoren auf die Haufigkeit chronisch unspezifischen Atemwegserkrankungen. Intern. Arch. Arbeirsmed. 27, 130- 154. Schlipkoter. H. W., Schmidt, P.. and Pelech, L. (1973). Der Gesundheitszustand von Schulkindern in Luftverunreinigten Gebieten. Prtrc. Tlrird Inr. C/rrrn Air Congr., pp. A 59-A 62. Dltsse/dtrr$ Steiger, H.. and Brockhaus, H. (1971). Untersuchungen zur Mortal&it in Nordrhein-Westfalen wahrend der Inversions-wetterlage. Sttrub 31, 190- 192. Stuart Harris. C. Infection, the environment and chronic bronchitis. J. Rogd Co//. Ph.vsiciuns 5, 351-361. Sussman, W. H. (1971). New priorities in air pollution control. J.A.P.C.A. 21. 201~203. Syrota, N. (1973). Notes sur la lutte contre la pollution atmospherique. Pollut. AfmosphPriynr 15, 129-151. Syrota. M. (1974). Reseaux de messure de la pollution atmospherique a l’etranger. Pollnt. Atmosphkrique 16, 530. Truhaut, R. (1971). Le problbme des limites admissibles pour les polluants de l’air. Produirs et ProbIPmes Pharmaceuriqrres

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Tsunetoshi. Y ., er nl. Epidemiological study of chronic bronchitis with special reference to effect of air pollution. Intern. Arch. Arbritsmvd. 29, l-27. Wailer, R. E. (1971). Air pollution and community health. J. Royal Co//. Plzysiciuns 5. 362-368. Wailer, R. E.. et nl. (1974). Respiratory symptoms and ventilatory capacity in a cohort of Londoners born in 1-952- 1953. Intern. Symp. Eni,. Heulth. Paris. Wilson, W. E., Levy, A. and MacDonald, E. H. (1972). Role of SO, and photochemical aerosol in eye irritation from photochemical smog. En\,. Science Tech&. 6, 423427.