1 2005-2017 ozone trends and potential benefits of local measures as deduced from air quality 2 measurements in the north of the Barcelona Metropolitan Area

3 Jordi Massagué1, 2, Cristina Carnerero1, 2, Miguel Escudero3, José María Baldasano4, Andrés Alastuey1, Xavier 4 Querol1

5 1 Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Barcelona, 08034, Spain. 6 2 Department of Civil and Environmental Engineering, Universitat Politècnica de Catalunya, Barcelona, 08034, Spain. 7 3 Centro Universitario de la Defensa, Academia General Militar, 50090 Zaragoza, Spain. 8 4 Department of Projects and Construction Engineering (DEPC), Universitat Politècnica de Catalunya, 08028 Barcelona, 9 Spain. 10

11 SUPPLEMENTARY MATERIAL

12

13 FIGURES

14

a W 10 b N 42 30’ E 20 42°28'2.09"N 2° 3'55.71"E Vic Plain N

41°27'46.72"N 2°23'41.06"E N 41 30’

E 2 00’ E 2 30’

1500 Km 60 Km N 15

16 Figure S1. Selected regions for retrieval of OMI Tropospheric Column NO2 in yellow: (a) area along the S–N 17 axis (~3,040 km2) which includes northern Barcelona Metropolitan Area (BMA), the Vic Plain and an area of 18 the Pre-Pyrenean range to analyze quantitatively the time trends and patterns and (b) across Western 6 2 19 Europe (~6,514  10 km ) to analyze qualitatively the NO2 spatial patterns in the two scenarios considered

20 (when the amount of O3 in the Vic Plain is high and when it is low).

21 22

a BdC b MSC BER MAN R TON MNR MSY GRA MAT PLR MON ALC VGe CTL -3 -3 NO (µgm ) NO2 (µgm ) CON

JUN-AUG (0:00 to 23:00 h) JUN- AUG (0:00 to 23:00 h)

23

24 Figure S2. (a) Spatial variability of mean June–August NO (a) and NO2 (b) concentrations observed in selected 25 AQ sites. Data from Ciutadella (CTL), Palau Reial (PLR), Montcada (MON), Granollers (GRA), Montseny (MSY), 26 Manlleu (MAN), Tona (TON), Montsec (MSC), Bellver de Cerdanya (BdC), Berga (BER), Mataró (MAT), 27 Manresa (MNR), Vilanova i la Geltrú (VGe), Constantí (CON) and Alcover (ALC) air quality monitoring stations.

28 360 a 5 360 b 5

300 300 )

4 4 )

1

1

- - 240 240 3 3 180 180 2 2

120 120 wind speed (m s 1 wind speed (m s

60 60 1

wind direction (degrees) wind direction (degrees)

0 0 0 0 0 1 2 3 4 5 6 7 8 9 1011121314151617181920212223 0 1 2 3 4 5 6 7 8 9 1011121314151617181920212223 WD BCN WS BCN WD PTS WS PTS MON: 12 km N BCN CTL: Barcelona City O3 CTL norm. NO CTL norm. O3 MON norm. O3 GRA norm. GRA: 23 km N BCN NO2 CTL norm. NO MON norm. NO2 MON norm.

360 c 5 360 d 5

300 300 )

4 ) 4

1

1

- - 240 240 3 3 180 180 2 2

120 120 wind speed (m s wind speed (m s 1

60 1 60

winddirection (degrees) wind direction (degrees)

0 0 0 0 0 1 2 3 4 5 6 7 8 9 1011121314151617181920212223 0 1 2 3 4 5 6 7 8 9 1011121314151617181920212223 WD TAG WS TAG TON: 53 km N BCN WD GUR WS GUR MSY: 45 km N BCN O3 MSY norm. NO MSY norm. VIC: 63 km N BCN O3 MAN norm. O3 TON norm. NO2 MSY norm MAN: 72 km N BCN O3 VIC norm. NO2 TON norm.

360 5 e NUR 300

4 ) PAR

1 - 240 3 180 MAN 2 GUR 120 VIC TON

1 wind speed (m s 60 MSY wind direction (degrees) wind TAG 0 0 GRA N 0 1 2 3 4 5 6 7 8 9 1011121314151617181920212223 PTS WD NUR MON PAR: 105 km N BCN WS NUR CTL BCN O3 PAR norm. 29

30 Figure S3. Normalized O3, NO and NO2 cycles and wind patterns for July (wind coming direction in the left

31 vertical axis and wind speed in the right vertical axis). Pollutants’ concentrations (O3, NO and NO2) are 32 normalized to the highest average value to emphasize the shape of the cycles, in the case of more than one

33 O3 cycle in a graph (b and d plots), the O3 concentrations are normalized to the highest O3 values of the site 34 that measured them. July average wind speeds and directions data come from meteorological stations 35 located near the corresponding AQ sites (air quality CTL monitoring site with meteorological BCN; air quality 36 MON and GRA monitoring sites with meteorological PTS; air quality MSY monitoring site with meteorological 37 TAG; air quality TON, VIC and MAN monitoring sites with meteorological GUR; air quality PAR monitoring site 38 with meteorological NUR). The map shows the location of air quality monitoring sites (white codes; squares) 39 and close meteorological sites (red codes; circles) grouped by pointed circles. Air quality data are from

40 monitoring sites along the S–N axis. In general, the highest O3 levels occur when the wind blows from the 41 south (location of the Barcelona Metropolitan Area, BMA) at its maximum velocity, confirming the clear 42 influence of the BMA plume transport.

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