P E R G A M O N Atmospheric Environment 35 Supplement No. 1 (2001) S107-Sl13

ATMOSPHERIC ENVIRONMENT

www.elsevier.com/locate/atmosenv

The Lagrange Street story: the prevention of aromatics pollution during the last nine years in a European city

Roberto Bono*, Elva H. Bugliosi, Tiziana Schilir6, Giorgio Gilli Department of Public Health and Microbiology, University of Torino, Via Santena 5 bis, Torino 10126, ltaly

Received 4 May 2000; received in revised form 18 December 2000; accepted 9 January 2001

air

Abstract

Benzene, toluene and xylenes (BTX) air pollution is a very important topic for environmental health, due to the toxicity and/or mutagenetic or carcinogenetic properties of these aromatics and the commercialisation of the unleaded gasoline containing amount of BTX. We measured BTX in the air of Turin city, the capital of Piedmont region (north-western Italy), during 10 years, from 1989 to 1998. The sampling site selected was Lagrange Street (LS), an "urban canyon" placed in the centre of the city. The behaviour of BTX in LS was conditioned by some local and national legislative measures enforced during 1990s for the reduction of automotive traffic and BTX air pollution, respectively. Taking into account the existence of similar measures undertaken also in several cities in the developed countries, largely described but never discussed, the aim of this study was to verify in LS the preventive effects of these regulatory actions by means of a longitudinal survey extended over 10 years. Results obtained in Lagrange Street highlight seasonal trends, typical of this kind of pollutants, and an important reduction (from 42.6 to 15.9 ppbv) of aromatic hydrocarbons (sum of benzene, toluene and xylenes) in atmospheric air from 1990 to 1997. In particular, the annual level of benzene in air showed a mean from 9.2ppbv in 1990 to 2.0ppbv in 1997, almost half of the 3.1ppbv imposed by law since 31 December 1998. In conclusion, the present findings induce a consistent optimism about the usefulness and the effectiveness of these types of regulatory actions enforced to reduce the human exposure to BTX, which could be extended also to other trafficated sites where the aromatics air pollution has to be reduced. © 2001 Elsevier Science Ltd. All rights reserved.

Keywords: Air pollution trend; Automotive emission; Benzene; Toluene; Xylenes; Health impact

1. Introduction

Benzene, toluene, and xylenes (BTX) are present in the environment, primarily in air (99%), because of emissions from automobiles, petrochemical industry, and combus- tion processes. Moreover, active smoke represents the most important source of benzene exposure for humans. For nonsmokers, however, BTX exposure ultimately de- rives from autoexhaust or gasoline vapour emissions, inhaled from the outdoor air in general and from per- sonal activities such as driving in particular (Wallace, 1996).

Aromatic hydrocarbons air pollution is a very impor- tant topic for environmental health due tO the toxicity

* Corresponding author. E-mail address." roberto.bono@unito.it (R. Bono).

and/or mutagenetic or carcinogenetic properties of BTX. In particular, benzene is characterised as a known human carcinogen for all routes of exposure (U.S. EPA, 1979, 1986, 1993, 1998; IARC, 1982, 1986), in the proposed revised Carcinogen Risk Assessment Guidelines (U.S. EPA, 1986, 1995, 1996a). Habitual inhalation of toluene or xylenes may induce brain functions disturbances, with effects on speech, vision, hearing, muscle control and balance and induce kidney and liver damage (Snyder and Kalf, 1994; Smith, 1996) while the body of knowledge on the carcinogenicity effects of toluene and xylenes is still based on inadequate or sparse evidences (IPCS, 1985, 1997). Nevertheless, an increased risk of gastrointestinal tumours and lymphohaematopoietic malignancies has been reported among persons with substantial exposure to toluene and xylenes (Siemiatycki, 1991; Svensson et al., 1990; IPCS, 1997; Gerin et al., 1998). Two studies

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suggested an association between toluene and xylenes exposure and brain tumors (Persson et al., 1993; D'Amore, 1992).

Considering the toxicological and genotoxicological properties of the three aromatics, the commercialisation of the new unleaded gasoline containing amounts of benzene, toluene and xylenes should be taken into ac- count. The change from leaded to unleaded gasoline, in fact, represents the transformation of a risk factor for the human population chronically exposed to urban air pol- luted by automobile smokes (Gilli et al., 1996).

In order to estimate the presence, the levels and the health risk due to these pollutants in atmosphere, we measured benzene, toluene and xylenes in the air of Turin city, the capital of Piedmont region (north-western Italy), during 10 years (from 1989 to 1998). The sampling site selected was Lagrange Street (LS), an "urban canyon" placed in the centre of the city. During this period, the behaviour of benzene, toluene, and xylenes in LS was conditioned by local (a) and national (b) legal measures aiming to reduce automotive traffic and BTX air pollu- tion, respectively.

(a) Until the early 1990s, Lagrahge Street showed a particularly severe pollution due to an intense automo- tive traffic. Therefore, starting from 26 February 1990, a Limited Traffic Zone in the area including LS was instituted. Thereafter, further specific restrictions in auto- mobile traffic were introduced in LS: the enforcement of parking-meters and the imposition of one-way route with public transports in opposite direction (since 16 August 1994), etc.

(b) Two national acts enforced to limit the potential increase of aromatic hydrocarbons in air were imposed by the Italian Government on specific air quality stan- dards (DM 25 November 1994) and on specific steps preventing the atmospheric benzene pollution (Law no. 413, November 1997). The above mentioned DM was enforced in Italy aiming to gain the air quality objectives in urban areas with over 150000 inhabitants. This law imposed in these cities, from 1 January 1996 to 31 De- cember 1998 an objective of quality for benzene (annual average) of 4.65ppbv and, from 1 January 1999 of 3.1 ppbv. Several measures were adopted in Italy to at- tain this objective: traffic restrictions, commercialisation of catalysed new cars, reformulation of gasoline, devices to extract the vapours in gasoline pumps. The last two objectives were pursued by the above mentioned Law no. 413: starting from 1 July 1998 the maximum content in volume of benzene gasoline is fixed in 1% and the total aromatic hydrocarbons are limited to 40% in volume. Another important item of the Law no. 413 imposes that new gasoline pumps must be equipped with vapours inspirators and that before 1 July 2000, all the gasoline pumps must adequate to these requirements.

The aim of this study was therefore to verify in LS the effects of the above mentioned local regulatory and pre-

I TURIN CITY

L LAGRANGE STREET 1

Fig. 1. Lagrange Street, Turin city, Italy.

ventive actions to limit automotive traffic in the centre of Turin city and to verify in the same street the efficacy of specific Italian laws to reduce the automotive emissions of aromatic hydrocarbons. In particular, by means of BTX measurements for 10 years in the air of Lagrange Street, we investigated the environmental effects of the above mentioned direct or indirect differentiated actions to reduce benzene, toluene and xylenes air pollution. This longitudinal survey was performed taking also into ac- count similar phenomena described in several cities in the developed countries, largely reported but never discussed (IPCS, 1993; U.S. EPA, 1996b; Wallace, 1996).

2. Material and methods

Measurements of benzene, toluene, and xylenes pollu- tion were carried out in Lagrange Street during two periods (from October 1989 to January 1993 and from May 1994 to July 1998). Lagrange Street is a typical urban canyon placed in the centre of Turin, the capital of Piedmont region (north-western Italy) with almost one million of inhabitants (Fig. 1).

Sampling was performed for 12months/year, 10 con- secutive days/month, 24 h each day. All the measurements

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10

9

8

7

6

5

4

3

2

1

0

7,04

5,73

2,23 1,98

1990 1991 1992 1994 1995 1996 1997

Fig. 2. Annual mean of the 7 years completely monitored in Lagrange Street.

60.0

55.0

50.0

45.0

A. Benzene (ppbv). October 1989, January 1993.

y -0,0224x + 11,924 RZ = 0,1137

40.0

35.0

30.0

25.0

20.0

15.0

10.0

5.0

0.0

60.0

days - - days

B. Benzene (ppbv) May 1994, July 1998.

y = -0,0155x + 6,994 R 2 = 0,2765 55.0

50.0

45.0

40.0

35.0

30,0

25.0

10.0

Fig. 3. Complete daily data of benzene (ppbv) during the period October 1989-January 1993 (A) and period May 1994-July 1998 (B). Linear regressions (with intercepts, slope and R 2) and mobile averages are also reported. Line at 3.1 ppbv represent the objective of quality from 31 December 1998 in Italy (DM 25 November 1994).

were carried out using a fixed sampling line (air flow = 11/min) consisting of a membrane pump, a gas meter, and a granular activated carbon (GAC) cartridge. Air was sampled at 1.5 m above ground and 2.0 m from the curb.

2.1. Analytical technique

Analysis of samples (injection = 1 gl) were made using a gas chromatograph "Carlo Erba 5300 Mega Series"

equipped with a Flame Ionisation Detector and capillary column DB-624 30mx0.318mm ID, film 1.8gin. A calibration curve suitable for the range of concen- trations expected was prepared by addition of known concentration of benzene, toluene and xylenes in CS2 ultrapure. In particular, the following concentrations were chosen for preparation of the calibration curve: benzene 2.2-4.4-8.8-17.6-35.3-70.4 Ixg/ml; toluene 2.15-4.3 -8.6-17.2-34.4-68.8pg/ml; xylenes 2.18-4.35-8.7-17.4 -34.8-69.6gg/ml. GC thermal program was: 45°C for

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25.0

20.0

15.0

10.0

5 .0

0 .0

25.0

20.0

15.0

lO.O

5.0

0.0

A. benzene oct .89, sep t .90

• y= - 0 , 0 9 7 4 x + 15 ,879

days

C. b e n z e n e oct .91, sept .92

y = -0,0824x + 10,224 R 2 = 0,1304

days

25,0

20.0

15.0

10.0

5.0

0.0

25,0

20,0

15.0

10,0

5.0

0 .0

B. b e n z e n e o c t , 9 0 , s e p t . 9 1

y = - o , o 8 6 8 x + 12 ,455 R 2= 0 ,2192

days

D. b e n z e n e o c t . 9 4 , s e p t . 9 5

y =-0,0326x + 7,7165 ] R 2 = 0,0324

I

days

25.0

20.0

15.0

lO.O

5.0

0.0

E. benzene oct .95 sept .96

y = -0,0512x + 5,7951 R 2 = 0,2759

days

25.0

20.0

15.0

10.0

5 .0

0 .0

F. b e n z e n e o c t . 9 6 , s e p t . 9 7

. . . . . . . . y'= "0 ,o174x + 31122' R 2 = 0,1357

days

Fig. 4. Linear regressions and mobile averages (n = 10) of six periods (12months from October to September). Intercepts, slopes and R 2 are also reported.

4min-from 45°C to 145°C, with an increase of 10°C/min-145°C for 2 min.

2.2. Quality control

The limit of detection of at least 0.2 gg/sampler was calculated for the three aromatics with a signal-to-noise ratio of at least 5-1. The precision of the analysis was determined by analysing a sample 20 times. The average of the 20 injections into GC/FID referred to benzene was 2.91ppbv (SD = 0.15) with a coefficient of variation of 4.3%. Recovery (95%) was calculated using previously described techniques (Gilli et al., 1991).

2.3. Statistical analysis

Statistical analysis was performed using SPSS Pack- age, Version 8.0. (SPSS, 1998). In particular, to estimate

the tendency lines, the method of the running means was adopted, imposing an overlap of 30 data.

3. Results

Benzene air pollution shows a decreasing intensity with years. Fig. 2 reports the annual averages only for the seven years completely monitored from January to December. Benzene concentrations displayed a general decrease over time. The trend, however, proved non- homogeneous and nonconstant being directly correlated to the time when the efforts to reduce ambient BTX levels were enforced and to the reduction of the amount of benzene in petrol operated by petrol companies. Fig. 3 shows the complete daily data of benzene in LS from October 1989 to January 1993 (part A) and from May 1994 to July 1998 (part B). Intercepts, slopes and running

R. Bono et al. / Atmospheric Environment 35 Supplement No. 1 (2001) $107-$113 Si l l

mean of the two linear regressions demonstrate the de- creasing concentration trend of benzene. In particular, the first years of monitoring (A) show a steeper slope ( - 0.0224 versus - 0.0155) followed (B) by a slower but still continuously decreasing trend (intercepts 11.924 ver- sus 6.994). The line at 3.1 ppbv is the objective of quality from 31 December 1998 in Italy (DM 25 November 1994). Finally, the seasonal trend of benzene is evidently shown in the whole period of time by the running means.

A more detailed longitudinal analysis of benzene air pollution in LS is reported in Fig. 4 where the single daily data are omitted but linear regressions and running means are reported year by year. The parts of Fig. 4 iden- tified with A-C, report three complete years (from Octo- ber to September) of the first period while, the parts D-F , three complete years of the second period. In these 6 years the linear regressions show a temporal decrease of benzene air pollution as displayed by the decreasing levels of the intercepts. Slopes, always negative, were in constant reduction showing a phenomenon almost normalised in part F.

Fig. 5 shows the daily data of sum of BTX from October 1989 to January 1993 in part A and from May 1994 to June 1998 in part B. Linear regressions and running means of BTX trends are reported for the two periods. Slopes of -0 .073 and 0.0602 and intercepts of 52.046 and 34.326, respectively, are also reported. Temporal trend of BTX in the two periods are similar to that of benzene with an annual average of 42.6 ppbv in 1990 reduced to 15.9ppbv in 1997.

The three aromatics clearly show a higher concentra- tion during winter, when the minor mixing ratio in the atmosphere increases the concentration of these air pol- lutants. The subdivision of benzene air contamination in LS in winter periods (from October to March) and sum- mer periods (from April to September) is reported for

150

135 I

120

105

90

75

60

45

30

15

0

part A

y = -0,073x + 52,046

130 t 120 t 11o 1

part B

y = -0,0602× + 34,326 r 2 = 0,2684

80 70 60

30

2O

10

0

Fig. 5. Complete daily data of sum of benzene, toluene and xylenes (ppbv) during the period October 1989-January 1993 (part A) and period May 1994-July 1998 (part B). Linear regres- sions (with intercepts, slopes and R 2) and running means are also reported.

these 6 years in Fig. 6. During the coldest months levels of benzene are always significantly higher (p < 0.0001), con- firming the seasonal trend just previously showed.

16

14-

12-

10-

6 -

4 -

2 -

0 -

• winter ] • summer

1989/90 1990/91 1991/92 1994/95 1995/96 1996•97

Fig. 6. Means of daily data of benzene in LS subgrouped by season. Winter data consist of months from October to March; summer data consist of months from April to September.

Sl12 R. Bono et al. /Atmospheric Environment 35 Supplement No. 1 (2001) S107-Sl13

4. Discussions and conclusions

Benzene, toluene and xylenes show higher concentra- tions during winters, proving their primary pollutant nature. This behaviour depends exclusively on the minor mixing ratio during the coldest months which allows an accumulation of pollutants in the lowest layers of the atmosphere; the seasonal variation of aromatics pollu- tion could not be attributed either to the traffic volume or to the aromatic content of gasoline.

Results obtained in Lagrange Street highlight an im- portant reduction over time of the three aromatic hydro- carbons concentration in atmospheric air. In particular, the actual annual level of benzene in air is almost half of the 3.1 ppbv, imposed by law since 31 December 1998 as the maximum level. Taking into account the future ben- zene air limit of 1.55 ppbv, that will be enforced by the European Community within 2001, our data demon- strate that Turin city is almost within acceptable limits.

The present findings represent an original description and explanation of a general phenomenon reported, but not discussed, in several European and US urban areas. The National Air Quality and Emission Trends Report, 1998, published by the EPA Office of Air Quality Plann- ing and Standards, confirmed a decrease of 39% for benzene and 44% for toluene during the period 1993-1998 in several US cities, and showed annual aver- age concentrations of benzene and toluene similar to the LS data for Turin.

In order to estimate the importance of the single na- tional or local legislative measures adopted in Italy to reduce BTX in air, we subdivided the whole survey in two periods: 1989-1992 and 1994-1998. Figs. 3 and 5 re- lated to this subdivision show a stronger decrease in concentration of benzene (72% versus 41%) and BTX (57% versus 29%).

In details, considering that the main sources of ben- zene in air (from 70% to 93%) are the production, distri- bution and use of automotive fuels (Holman, 1999), the temporal decrease in concentration of benzene and BTX may be largely attributed to the following events:

(a) the increased number of catalytic cars matriculated in the last 10years deducible by the percentage of unleaded gasoline sold in Italy from 199l (3%) to 1997 (37.4%),

(b) the general improvement of energetic yield in new engines, as demonstrated by the reduction of CO in air,

(c) the reduction of benzene in Italy from 3.7% to the actual 1% in volume in leaded and unleaded gasoline since 1989.

(d) the restrictions of private traffic in central area of Turin city and of Lagrange Street in particular.

The singular associations between the reductions of BTX pollution in LS and the specific national or local

legislative measures mentioned above are complex. In particular, we cannot explain the steeper decrease of aromatics in air during the first period considered. In fact, all the legislative measures previously mentioned started (officially or preventively) around 1990 or later and they are still in force today. The higher level of BTX pollution in Lagrange Street air during the early 1990s probably allowed, during that period, more remarkable effects on the reduction of air pollution due to these preventive measures. On the whole, it can be gathered that the incontrovertible decreases in air of BTX in gen- eral, and of benzene in particular, were certainly induced by all these different legislative measures in harmony with one another.

In conclusion, present findings induce a real optimism about the usefulness and the effectiveness of these types of regulatory actions which could be enforced also in other tralficated sites where the human health risk due to this type of air pollution has to be reduced.

Acknowledgements

This study was made possible by a grant from Minis- tero dell'Universitfi, della Ricerca Scientifica e Tec- nologica (60%), 1999.

References

D'Amore, F., Hasle, H., Hansen, K.S., 1992. Occupational expo- sures and non-Hodgkin's lymphoma. Hematologic Reviews 6, 183-199.

Gerin, M., Siemiatycki, J., Desy, M., Krewski, D., 1998. Associ- ation between sites of cancer and occupational exposure to benzene, toluene, xylenes, and styrene: results of a case-con- trol study in Montreal. American Journal of Industrial Medicine 34 (2), 144-156.

Gilli, G., Bono, R., Brezzo, E., Guerrini, E., Scursatone, E., 1991. VHH atmospheric concentration in urban/rural areas and biological monitoring. Journal of Toxicology and Environ- mental Chemistry 31 (32), 39-48.

Gilli, G., Scursatone, E, Bono, R., 1996. Geographical distribu- tion of benzene in air in north-western Italy and personal exposure. Environmental Health Perspectives 104 (Suppl. 6), 1137-1140.

Holman, C., 1999. Sources of air pollution. In: Holgate, S.T., Samet, J.M., Koren, H.S., Maynard, R.L. (Eds.), Air Pollu- tion and Health. Academic Press, San Diego, London, Bos- ton, New York, Sydney, Tokyo, Toronto, pp. 115-148.

International Agency for Research on Cancer (IARC), 1982. IARC Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans. Some Industrial Chemicals and Dyestuffs. WHO, IARC.

International Agency for Research on Cancer (IARC), 1986. IARC Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans. Tobacco Smoking. 38, WHO, IARC.

R. Bono et al. / Atmospheric Environment 35 Supplement No. 1 (2001) S107-S l13 Sl13

International Programme on Chemical Safety (IPCS), 1985. Environmental Health Criteria 52; Toluene, WHO, Geneva, ISBN 92 4 1 54192 X.

International Programme on Chemical Safety (IPCS), 1993. Environmental Health Criteria 150; Benzene, WHO, Geneva, ISBN 92 4 1 57150 0.

International Programme on Chemical Safety (IPCS), 1997. Environmental Health Criteria 190; Xylenes, WHO, Geneva, ISBN 92 4 157190 X.

Persson, B., Fredriksson, M., Olsen, K., Boeryd, B., Axelson, O., 1993. Some occupational factors for malignant lymphomas. Cancer 72, 1773-1778.

Siemiatycki, J., 1991. Risk Factors for Cancer in the Workplace. CRC Press, Boca Raton, FL, pp. 1-325.

Smith, M.T., 1996. The mechanism of benzene-induced leukae- mia: a hypothesis and speculations on the causes of leukae- mia. Environmental Health Perspectives 104, 1219-1225.

Snyder, R., Kalf, G., 1994. A perspective on benzene leukemogen- esis. Critical Reviews in Toxicology 24 (3), 177-209.

SPSS, 1998. SPSS Inc. Packages, Version 8.0. Svensson, B.G., Nise, G., Englander, V., Attewell, R., Skerfving,

S., M611er, T., 1990. Deaths and tumors among rotogravure printers exposed to toluene. British Journal of Industrial Medicine 47, 372-379.

U.S. EPA, 1979. Carcinogen assessment. Group's final report on population risk to ambient benzene exposures. National Technical Information Service. PB82-227372.

U.S. EPA, 1986. Guidelines for carcinogenic risk assessment. Federal Register 51(185), 33992-34003.

U.S. EPA, 1993. Motor vehicle-related to toxic study, Report No. EPA 420-R-93-005. USEPA, Office of Mobile Sources, Emission Planning and Strategies Division, Ann Arbour, MI, April, 1993.

U.S. EPA, 1995. Interim quantitative cancer unit risk estimates due to inhalation of benzene. Prepared by the Carcinogen Assessment Group, Office of Research and Development, Washington, DC. EPA/600/X-85-022.

U.S. EPA, 1996a. Proposed guidelines for carcinogen risk as- sessment. Federal Register 61(79), 17960-18011,

U.S. EPA, 1996b. National air pollutant emission trend, 1900-1996. EPA-454/R-97-011, December 1997.

U.S. EPA, 1998. Carcinogenic effects of benzene: an update. Prepared by the National Centre for Environmental Health, Office of Research and Development. Washington, DC. EPA/600/P-97/001F.

Wallace, L., 1996. Environmental exposure to benzene: an update. Environmental Health Perspectives 104 (6), 1129-1136.