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Ozone levels in Paris one century ago
Pergamon
Atmospheric Emironment Vol. 31, No. 20, pp. 3481 3482, 1997 PII:
S1352-2310(97)00124-6
~E 1997 Elsevier Science Ltd All rights reserved. Printed in Great Britain 1352 2310/97 $17.00 + 0.00
SHORT C O M M U N I C A T I O N O Z O N E LEVELS IN PARIS O N E C E N T U R Y A G O D. ANFOSSI* and S. SANDRONI t * lstituto di Cosmogeofisica del CNR, Torino, Italy; and tlstituto di Fisica Generale Applicata dell'Universit~i, Milano, Italy
(First received 22 August 1996 and in flnal form 1 March 1997. Published August 1997) Abstract--Based on a procedure for re-evaluating historical ozone data previously developed by the authors, ozone observations by the Schoenbein method in the Paris air quality network during 1876 were discovered, re-analysed and a yearly ozone level map was derived. ~ 1997 Elsevier Science Ltd.
Key word index: Historical ozone, urban air quality.
Paris was one of the first towns in Europe to have an air quality monitoring network. In 1865 the Prefecture du Departement de la Seine wanted to map the air quality in the city and a network of 20 stations distributed in different quarters was set up. Each station was equipped with some meteorological instruments and/or ozone monitors. Daily observations were centralised by Albert Levy, chemist at the Observatory of Montsouris and regularly published (Bulletin de la Statistique Municipal de la Ville de Paris). The network operated for more than ten years; its structure changed in time (some stations were at unhealthy sites, others were moved) until it was dismantled. We have focused in particular our attention on ozone observations. Historically, ozone was recognised as an atmospheric trace constituent around 1840 by F. Schoenbein (1840) who developed a monitoring technique later used in many meteorological observatories of the world. At that time ozone was considered as index of healthy air: a high level meant a low risk of epidemic diseases. The monitoring technique was quite simple: a paper strip embedded with a paste of KI and starch changes to violet when exposed to air. The ozone level was evaluated as colour intensity after a 12 h exposure by a reference scale, as Schoenbein (0-10) or Salleron (0-21) units. Observations were routinely made day and night along years. The interest in tropospheric ozone in the last decades has promoted a re-analysis of observations made one century ago. With reference to data series of parallel observations by the Schoenbein paper-strip and wet-chemistry methods and to previous studies, we have developed a two-step procedure to convert Schoenbein numbers into present-time units (ppbv) (Anfossi et al., 1991). This procedure has been applied to re-evaluate historical data series available by many observatories, in different continents at different latitudes and heights, as the ozone trend (Anfossi et al., 1991; Anfossi and Sandroni, 1994; Sandroni et al., 1992; Sandroni and Anfossi, 1994, 1995). As mentioned above, at Montsouris, near Paris, along some months of 1876 daily ozone levels were simultaneously measured by colorimetric technique (in Salleron units) and a chemical method (in mg (100 m 3 of air)-1). The parallel data series have largely contributed to assess the conversion procedure even for data from the Paris monitoring network.
Since preparation and reading of paper strips were made at Montsouris, some sources of error were reduced. We have analysed historical data of the Paris network, published in the Bulletin de la Statistique Municipal de la Ville de Paris (Pelletier, 1876-1877). As the network structure changed in time, we have focused our attention on 1876. when 16 stations (listed in Table 1) were in full operation. In the conversion procedure we have assumed a constant relative humidity as available at the Montsouris Observatory. Figure 1 shows the reconstructed yearly mean distribution of ozone in Paris for 1876. High levels were reached on the outskirts (10.6 ppbv at Montsouris; 7.9 ppbv at Montmartre Passage Cottin, a hilly site). By contrast low levels 13-4 ppbv) were reached in the city centre, where reducing agents (SO2 and NH3) were present. As mentioned elsewhere (Anfossi et al., 1991), the Schoenbein technique as the conversion procedures are affected by uncertainties, which have been already considered in a detailed analysis of the observations of Montsouris Observatory. The accuracy of the conversion procedure, evaluated from the simultaneous measurements by the arsenite and the Schoenbein methods is 33 % (Anfossi et al., 1991), equivalent to 2 - 3 ppbv. Furthermore, Schoenbein readings are sensitive to experimental procedure: the standardisation of apparatus, exposure time and reading allows the data comparability to the observations made at Montsouris. Finally~ the Schoenbein method (as the arsenite one) suffers from chemical interferences, positive (such as NO2 and H202) and negative (mainly SO2 and NH3), the last ones being dominant. In a previous and accurate analysis of historical data of Montsouris, Volz and Kley (1988) evaluated a significant contribution only for SO2, of the order of 2 ppbv ozone equivalent. For stations located in the central quarters of Paris, the level of interferences during those years cannot be evaluated. An evaluation of accurate levels of ozone is, however, outside the purpose of our study: the lower levels observed in central areas of the town in comparison to the outskirts play for a contribution of negative interferences. Within the above-mentioned intrinsic limitations of the procedure, the calculated ozone distribution in the Paris agglomeration is similar to present-time observations. As far as we know, the map shown in Fig, 1 is the oldest map of ozone level in an urban area: it follows the map of
3481
3482
Short Communication
8 9
15
"1112 *
16
6_
%
0
1 km l
Fig. 1. Isolines of ozone levels in Paris in 1876 from re-evaluated historical observations. Full points refer to the monitoring stations listed in Table 1.
Table 1. Ozone monitoring stations in Paris in 1876 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Parc de Montsouris Reservoire de Passy Reservoire Monceaux Montmartre, passage Cottin La Villette Charonne (Reservoire) Boulevard de Picpus Boule Rouge Fontaine Mo|iere Rue de l'Ecole de Medicine Rue Racine Pantheon Saint Victor Boulevard d'Italie Reservoire de Vaugirard Vaugirard, Rue de l'Abbe Groult
sulphate content in rain of London for the years 1869-1870 mentioned by Brimblecombe (1987).
REFERENCES
Anfossi, D. and Sandroni, S. (1994) Surface ozone at mid latitudes in the past century. Nuovo Cimento 17C, 199-208.
Anfossi, D., Sandroni, S. and Viarengo, S. (1991) Tropospheric ozone in the nineteenth century: the Moncalieri series. Journal of Geophysics Research 96 (9D), 17,349 17,352. Brimblecombe, P. (1987) The Bi9 Smoke. Methuen, London. Bulletin de la Statistique Municipal de la Ville de Paris Direction de l'Administration General, Prefecture du Departement de la Seine, Charles de Morgues Freres, Paris. Levy, A. (1877) Annuaire de I'Observatoire de Montsouris pour l' an 1876. Gauthier-Villars, Paris. Sandroni, S. and Anfossi, D. (1994) Historical data of surface ozone at tropical latitudes. Science of the Total Environment, 148, 23-29. Sandroni, S. and Anfossi, D. (1995) Trend of ozone in the free troposphere above Europe. Nuovo Cimento 18C, 497 503. Sandroni, S., Anfossi, D. and Viarengo, S. (1992) Surface ozone levels at the end of the 19th century in South America. Journal of Geophysics Research 97 (D2), 2535 2539. Schoenbein, C. F. (1840) Recherche sur la nature de l'odeur qui se manifeste dans certaines actions chimiques. Comptes Rendus des Seances Paris 10, 706-710. Volz, A. and Kley, D. (1988) Evaluation of the Montsouris series of ozone measurements made in the nineteenth century. Nature 332, 240-242.
Atmospheric Emironment Vol. 31, No. 20, pp. 3481 3482, 1997 PII:
S1352-2310(97)00124-6
~E 1997 Elsevier Science Ltd All rights reserved. Printed in Great Britain 1352 2310/97 $17.00 + 0.00
SHORT C O M M U N I C A T I O N O Z O N E LEVELS IN PARIS O N E C E N T U R Y A G O D. ANFOSSI* and S. SANDRONI t * lstituto di Cosmogeofisica del CNR, Torino, Italy; and tlstituto di Fisica Generale Applicata dell'Universit~i, Milano, Italy
(First received 22 August 1996 and in flnal form 1 March 1997. Published August 1997) Abstract--Based on a procedure for re-evaluating historical ozone data previously developed by the authors, ozone observations by the Schoenbein method in the Paris air quality network during 1876 were discovered, re-analysed and a yearly ozone level map was derived. ~ 1997 Elsevier Science Ltd.
Key word index: Historical ozone, urban air quality.
Paris was one of the first towns in Europe to have an air quality monitoring network. In 1865 the Prefecture du Departement de la Seine wanted to map the air quality in the city and a network of 20 stations distributed in different quarters was set up. Each station was equipped with some meteorological instruments and/or ozone monitors. Daily observations were centralised by Albert Levy, chemist at the Observatory of Montsouris and regularly published (Bulletin de la Statistique Municipal de la Ville de Paris). The network operated for more than ten years; its structure changed in time (some stations were at unhealthy sites, others were moved) until it was dismantled. We have focused in particular our attention on ozone observations. Historically, ozone was recognised as an atmospheric trace constituent around 1840 by F. Schoenbein (1840) who developed a monitoring technique later used in many meteorological observatories of the world. At that time ozone was considered as index of healthy air: a high level meant a low risk of epidemic diseases. The monitoring technique was quite simple: a paper strip embedded with a paste of KI and starch changes to violet when exposed to air. The ozone level was evaluated as colour intensity after a 12 h exposure by a reference scale, as Schoenbein (0-10) or Salleron (0-21) units. Observations were routinely made day and night along years. The interest in tropospheric ozone in the last decades has promoted a re-analysis of observations made one century ago. With reference to data series of parallel observations by the Schoenbein paper-strip and wet-chemistry methods and to previous studies, we have developed a two-step procedure to convert Schoenbein numbers into present-time units (ppbv) (Anfossi et al., 1991). This procedure has been applied to re-evaluate historical data series available by many observatories, in different continents at different latitudes and heights, as the ozone trend (Anfossi et al., 1991; Anfossi and Sandroni, 1994; Sandroni et al., 1992; Sandroni and Anfossi, 1994, 1995). As mentioned above, at Montsouris, near Paris, along some months of 1876 daily ozone levels were simultaneously measured by colorimetric technique (in Salleron units) and a chemical method (in mg (100 m 3 of air)-1). The parallel data series have largely contributed to assess the conversion procedure even for data from the Paris monitoring network.
Since preparation and reading of paper strips were made at Montsouris, some sources of error were reduced. We have analysed historical data of the Paris network, published in the Bulletin de la Statistique Municipal de la Ville de Paris (Pelletier, 1876-1877). As the network structure changed in time, we have focused our attention on 1876. when 16 stations (listed in Table 1) were in full operation. In the conversion procedure we have assumed a constant relative humidity as available at the Montsouris Observatory. Figure 1 shows the reconstructed yearly mean distribution of ozone in Paris for 1876. High levels were reached on the outskirts (10.6 ppbv at Montsouris; 7.9 ppbv at Montmartre Passage Cottin, a hilly site). By contrast low levels 13-4 ppbv) were reached in the city centre, where reducing agents (SO2 and NH3) were present. As mentioned elsewhere (Anfossi et al., 1991), the Schoenbein technique as the conversion procedures are affected by uncertainties, which have been already considered in a detailed analysis of the observations of Montsouris Observatory. The accuracy of the conversion procedure, evaluated from the simultaneous measurements by the arsenite and the Schoenbein methods is 33 % (Anfossi et al., 1991), equivalent to 2 - 3 ppbv. Furthermore, Schoenbein readings are sensitive to experimental procedure: the standardisation of apparatus, exposure time and reading allows the data comparability to the observations made at Montsouris. Finally~ the Schoenbein method (as the arsenite one) suffers from chemical interferences, positive (such as NO2 and H202) and negative (mainly SO2 and NH3), the last ones being dominant. In a previous and accurate analysis of historical data of Montsouris, Volz and Kley (1988) evaluated a significant contribution only for SO2, of the order of 2 ppbv ozone equivalent. For stations located in the central quarters of Paris, the level of interferences during those years cannot be evaluated. An evaluation of accurate levels of ozone is, however, outside the purpose of our study: the lower levels observed in central areas of the town in comparison to the outskirts play for a contribution of negative interferences. Within the above-mentioned intrinsic limitations of the procedure, the calculated ozone distribution in the Paris agglomeration is similar to present-time observations. As far as we know, the map shown in Fig, 1 is the oldest map of ozone level in an urban area: it follows the map of
3481
3482
Short Communication
8 9
15
"1112 *
16
6_
%
0
1 km l
Fig. 1. Isolines of ozone levels in Paris in 1876 from re-evaluated historical observations. Full points refer to the monitoring stations listed in Table 1.
Table 1. Ozone monitoring stations in Paris in 1876 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Parc de Montsouris Reservoire de Passy Reservoire Monceaux Montmartre, passage Cottin La Villette Charonne (Reservoire) Boulevard de Picpus Boule Rouge Fontaine Mo|iere Rue de l'Ecole de Medicine Rue Racine Pantheon Saint Victor Boulevard d'Italie Reservoire de Vaugirard Vaugirard, Rue de l'Abbe Groult
sulphate content in rain of London for the years 1869-1870 mentioned by Brimblecombe (1987).
REFERENCES
Anfossi, D. and Sandroni, S. (1994) Surface ozone at mid latitudes in the past century. Nuovo Cimento 17C, 199-208.
Anfossi, D., Sandroni, S. and Viarengo, S. (1991) Tropospheric ozone in the nineteenth century: the Moncalieri series. Journal of Geophysics Research 96 (9D), 17,349 17,352. Brimblecombe, P. (1987) The Bi9 Smoke. Methuen, London. Bulletin de la Statistique Municipal de la Ville de Paris Direction de l'Administration General, Prefecture du Departement de la Seine, Charles de Morgues Freres, Paris. Levy, A. (1877) Annuaire de I'Observatoire de Montsouris pour l' an 1876. Gauthier-Villars, Paris. Sandroni, S. and Anfossi, D. (1994) Historical data of surface ozone at tropical latitudes. Science of the Total Environment, 148, 23-29. Sandroni, S. and Anfossi, D. (1995) Trend of ozone in the free troposphere above Europe. Nuovo Cimento 18C, 497 503. Sandroni, S., Anfossi, D. and Viarengo, S. (1992) Surface ozone levels at the end of the 19th century in South America. Journal of Geophysics Research 97 (D2), 2535 2539. Schoenbein, C. F. (1840) Recherche sur la nature de l'odeur qui se manifeste dans certaines actions chimiques. Comptes Rendus des Seances Paris 10, 706-710. Volz, A. and Kley, D. (1988) Evaluation of the Montsouris series of ozone measurements made in the nineteenth century. Nature 332, 240-242.