Supporting Information

Assessing temporal trends and source regions of per- and polyfluoroalkyl substances

(PFASs) in air under the Arctic Monitoring and Assessment Programme (AMAP)

Fiona Wonga, Mahiba Shoeiba, Athanasios Katsoyiannisb, Sabine Eckhardtc, Andreas Stohlc,

Pernilla Bohlin-Nizzettoc, Henrik Lid, Phil Fellind, Yushan Su a, e, Hayley Hunga, *

a Air Quality Processes Research Section, Environment and Climate Change Canada, 4905

Dufferin Street, Toronto, Ontario M3H 5T4, Canada

b Norwegian Institute for Air Research (NILU), FRAM - High North Research Centre for

Climate and the Environment, Hjalmar Johanssens gt 14, NO-9296 Tromsø, Norway

c Norwegian Institute for Air Research (NILU), PO Box 100, 2027 Kjeller, Norway

d Airzone One Ltd., 222, Matheson Blvd. E., Mississauga, Ontario L4Z 1X1, Canada

e Environmental Monitoring and Reporting Branch, Ontario Ministry of the Environment and

Climate Change, 125 Resources Road, West Wing, Etobicoke, Ontario M9P 3V6, Canada

*Corresponding Author:Hayley HungAir Quality Processes Research SectionEnvironment and Climate Change Canada4905 Dufferin StreetToronto, Ontario, M3H 5T4Telephone: 1-416-739-5944Facsimile: 1-416-739-4281E-mail: hayley.hung@canada.ca

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16171819202122232425

Table of Contents

S1 Sample preparation and analysis for PFASs

S2 Quality assurance and quality control (QA/QC) – Inter-laboratory studies

S3 Quality assurance and quality control (QA/QC) – Detection limits and data treatment

S4 Digital Filtration technique

S5 F-test for correlation of determination (r2) between the fitted trend and measured data

S6 Description of the source region analysis

Table S1 Target and qualifier ions for neutral PFASs analyzed by the GC-MS and allocation of internal (IS) and injection standards (InjS)

Table S2 Target and qualifier ions for PFAAs analyzed by the LC-MS/MS and allocation of internal (IS) and injection standards (InjS)

Table S3 PFASs in blanks of the Alert samples

Table S4 PFASs in blanks of the Zeppelin and Andøya samples

Table S5 Descriptive statistics of PFASs in air at Alert, Zeppelin and Andøya (pg m-3)

Table S6 Trend analysis for PFASs in air at Alert that were derived from data above a) IDL b) MDL.

Figure S1 Seasonal cycles and trends of FOSEs and FOSAs in Alert.

Figure S2 Fields of R80 for the highest 20% of all measured PFOSA at Zeppelin

Figure S3 Relative fields of R80 for PFOS and PFOA for the 2013 Alert data to the average of the overall data (excluding 2013 data)

Figure S4 Neutral PFAS vs. inverse temperature in air at Alert

Figure S5 PFAAs vs. inverse temperature in air at Alert

Figure S6 PFOSA vs. inverse temperature in air at Zeppelin

Figure S7 PFAAs vs. inverse temperature in air at Zeppelin and Andøya

References

S2

26

27

28

S1. Sample preparation and analysis for PFASs

Air samples from Alert were extracted using a pressurized liquid extraction system

(Accelerated Solvent Extraction System from Dionex Corporation, Sunnyvale, CA, USA). The

GFF and PUF/XAD/PUF cartridge trapped the particle- and gas-phase PFASs respectively, and

they were extracted together for samples collected from 2006 to 2014. The GFF and

PUF/XAD/PUF were extracted separately for samples collected after March 2014. Prior to

extraction, the GFF and PUF/XAD/PUF sandwich were spiked with 20 μL of 0.7 ng μL-1 internal

recovery standard (IS) mixture containing mass-labelled neutral PFASs: 13C2-6:2 FTOH, 13C2-8:2

FTOH, 13C2-10:2 FTOH, d3-MeFOSA, d5-EtFOSA, d7-MeFOSE and d9-EtFOSE; and 50 μL of

0.10 ng μL-1 of mass-labelled PFAAs, 13C-PFBA, PFHxA, PFOA, PFNA, PFDA, PFUnDA,

PFDoDA, PFOS; 18O2-PFHxS (see Table S1 and S2 for details). The air samples were first

extracted with 38 mL of hexane. Extraction was done at 50°C, 5 min static cycle with a 100%

flush at 800 psi. Then, the samples were extracted with 25 mL of methanol using the same

condition as the first extraction. The hexane and methanol fractions were concentrated by rotary

evaporation followed by gentle nitrogen blow-down to 1.0 mL. The hexane fraction was solvent

exchanged to ethyl acetate in 0.5 mL and subject to neutral PFASs analysis. The methanol

fraction was blown down to 0.5 mL and subject to PFAAs analysis. Prior to instrumental

analysis, 10 μL of 10 ng μL-1 of Me2FOSA was added to the ethyl acetate extract, and 10 μL of

0.01 ng μL-1 each of 13C8-PFOS and 13C8-PFOA to the methanol extract as injection standards

(InjS).

The separation and detection of the neutral PFASs was performed using gas

chromatography–mass spectrometry (Agilent 5975C; Agilent Technologies, Palo Alto, CA,

USA) (GC/MS) in selective ion monitoring (SIM) mode using positive chemical ionization mode

(PCI). Details on the analysis are given elsewhere (Ahrens et al., 2013).

The separation and detection of PFAAs were performed with ultra-performance liquid

chromatography (UPLC), tandem mass spectrometry using a Waters Acquity I-class UPLC

coupled with a Xevo TQ-S MS/MS, interfaced with an electrospray ionisation source operating

in negative ion mode (UPLC-(-)ESI-MS/MS). Aliquots of 1 μL were injected on a Cortecs C18

reversed phase analytical column (2.1 × 50mm, 1.6 µm particle size; Waters, Boston, USA).

S3

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

57

Column temperature was 45°C. A mobile phase program based upon (mobile phase A) 10 mM

ammonium acetate in water and (mobile phase B) 10 mM ammonium acetate in methanol at a

flow rate of 0.5 ml/min was applied, starting at 2% (mobile phase B) and increasing linearly to

100% (mobile phase B) over 3 min, holding for 1 min before reducing to initial conditions over

0.1 min. The column was equilibrated with 2% (mobile phase B) for 1 min after each run. For

the MS/MS, the capillary voltage was set at 2.7 kV, and the source and the desolvation

temperature were 150 and 600°C respectively. The desolvation and cone gas flows were set at

1000 and 150 L/hr respectively.

The isotope dilution method was used for quantification, which is based on ratio of the

response of the target analyte against the responses of their mass labelled surrogates. The target

and qualifier ion, and the allocation of injection and internal standards for the neutral PFASs and

PFAAs are provided in Tables S1 and S2. Note the reported concentrations for PFASs that lack

an authentic internal standard or lack a second product ion (e.g. PFBA and PFPeA) should be

considered as semi-quantitative.

The Alert air samples that were collected prior to October 2012, no mass-labelled PFAAs

internal standards were added prior to extraction, and quantification was achieved by using the

injection standards only. Thus, these samples were not recovery corrected and did not account

for the matrix effects during UPLC/MS/MS analysis.

The air samples from the Norwegian sites were extracted in methanol using ultra-

sonication (3x10 min). Prior to extraction, each GFF was spiked with 20 μL of 0.5 ng μL-1 IS

mixture. Between 2006 and 2011, the IS mixture contained 13C-labelled PFOA and PFOS while

from 2012 the IS-mixture contain 13C-labelled PFOSA, PFHxA, PFHpA, PFOA, PFNA, PFDA,

PFUnDA, PFHxS, PFOS, 6:2 FTS. The extract was then concentrated under nitrogen and

cleaned by acid treatment. Before quantitative analysis, 10 μL of 0.1 ng μL-1 of native 3, 7-

dimethyl PFOA was added as injection standard.

S4

58

59

60

61

62

63

64

65

66

67

68

69

70

71

72

73

74

75

76

77

78

79

80

81

82

S2 Quality assurance and quality control (QA/QC) – Inter-laboratory studies

Environment and Climate Change Canada (ECCC) has participated several inter-

laboratory studies for measuring PFAS in the air samples and standard solutions.

In 2007/2008, air samples were collected jointly by ECCC and Lancaster Environment

Centre (LEC). An overlapping period exists at two sampling locations in the Beaufort Sea.

Results from ECCC and LEC were in good agreement with an average relative standard

deviation of 34% (R = 0.93). The concentrations reported by ECCC and LEC differed by a mean

factor of 2.0 for 6:2 FTOH, 1.5 for 8:2 FTOH, 1.3 for 10:2 FTOH and 2.2 for EtFOSA (Ahrens

et al., 2011). This is a good agreement considering the challenges associated with sampling in a

remote area (i.e. Canadian Arctic) with very low PFAS concentrations in the atmosphere and

different sampling systems.

In 2010, ECCC participated an inter-laboratory comparison study for PFASs in air and

standard solutions (Dreyer et al., 2010). Results for most PFAS from ECCC were typically

within an order of magnitude to those reported from the other four participating laboratories.

ECCC regularly participates in the Northern Contaminants Program (NCP)/Arctic

Monitoring and Assessment Program (AMAP)’s Northern Contaminants QA/QC program.

Recent report shows that ECCC demonstrated satisfactory performance in the AMAP’s Inter-

laboratory study (Meyer and Reiner, 2017). Both labs (ECCC and NILU) are regular

participants of the UNEP bi-ennial Global Interlaboratory Assessment on POPs which include

the analysis of common PFAS in injection-ready solutions.

S5

83

84

85

86

87

88

89

90

91

92

93

94

95

96

97

98

99

100

101

102

103

S3 Quality assurance and quality control (QA/QC) – Detection limits and data treatment

Alert The ECCC data analysis protocol defines the instrumental detection limit (IDL) as the

amount of chemical (pg) in the lowest standard which gives a signal to noise ratio of 3 divided

by the average sampling volume, which is 2000 m3. Values below IDL were considered non-

detects and they were replaced with 2/3 IDL when performing statistical analysis. IDLs ranged

from 0.0063 to 0.12 pg m-3 for the neutral PFAS and 0.0063 to 0.031 pg m-3 for the PFAAs.

Method detection limit (MDL, pg m-3) was also calculated for reference and plotted in Figure 4

for selected PFASs. MDL is defined as mean blanks + 3 × standard deviation (SD). MDLs

ranged from 0.008 to 1.8 pg m-3 for the neutral PFASs and 0.008 to 0.79 pg m-3 for PFAAs. The

detection frequency and range concentrations of neutral PFAS and PFAAs in the blanks are

given in Table S3.

It is noted that in order to enhance detectability of target chemicals that usually occur in

Arctic air at trace levels, the sampling duration is 7 days, resulting in an average air volume of

2000 m3, which is greater than those in other surveillance studies (typically 300-600 m3 with

samples taken over 1-2 days). Hence, the detection limits reported by ECCC are generally lower

than other studies.

Zeppelin and Andøya The NILU data analysis protocol calculates the MDL for

individual sample as (mean blanks + 3 × SD)/sampled air volume of the specific sample. Hence,

each sample has its own MDL. Values below MDL were considered non-detected and replaced

with 2/3 MDL when performing statistical analysis. Annual averaged MDLs for all target

PFASs ranged from 0.01 to 1.3 pg m-3 for Zeppelin and 0.024 to 4.2 pg m-3 for Andoya. IDLs

were determined as the amount in the lowest standard which gives signal to noise ratio of 3

divided by the sampled air volume. Here, the IDLs for the target PFASs were estimated for

reference only, assuming sampling volume of 1200 m3. IDLs ranged from 0.00008 to 0.00042

pg m-3 for both Zeppelin and Andøya. The detection frequency and range concentrations of the

target PFASs in the blanks are given in Table S4.

S6

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

S4 Digital Filtration technique

A statistical fitting method called Digital Filtration (DF) technique is used to develop the

time trends and seasonal cycles for the targeted chemicals. The DF technique first applies a

smoothing Reinsch-type cubic spline and Fourier components to the measured data to

approximate the time trend and seasonal cycle, respectively. Outliers which are more than 3

standard errors away from the fitted curve are rejected. The fitting and outlier rejection

procedures are then repeated in an iterative manner until the fitted spline function becomes

almost unchangeable. Two Butterworth digital filters are then used to extract the long- and short-

term variations of the trend and the seasonal cycle with two cutoff periods. The cutoff periods

were chosen by trial-and-error based on visual inspection of the seasonal cycle, providing the

“best fit” to the specific data set. In this study, a short-term cutoff period of 4 months, and a

long-term cutoff period of 48 months were used; i.e. variabilities between 4 and 48 months were

extracted to obtain the overall seasonal cycle, and the variabilities >48 months were extracted to

provide the final time trend. It should be noted that the compounds do not necessarily

decline/increase linearly or consistently in the first order manner throughout the entire

monitoring period. These values are only used to compare the relative rates of decline/increase in

concentrations between chemicals. Readers are advised to use the absolute values of these half-

lives or doubling times with caution.

S7

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

S5 F-test for correlation of determination (r2) between the fitted trend and measured data

The coefficient of determination (r2) was calculated to assess the goodness of fit of the trend that is derived from the Digital Filtration model and the measured data. r is the generalized correlation coefficient, and it is defined by:

r=√∑ (Y est−Y m )2

∑ (Y m−Y m )2

Where Y est is the trend and Y m is the measured data. Y m is the average of the measured data and defined as:

Y m=( 1n )∑Y m

Where n is the number of measurements.

F-test was used to determine the significance of r2 . F is defined as:

F=v2r 2

v1 ( 1−r2 )

Where v1 and v2 are the degrees of freedom, where v1 is the number of variable, which is equal to 1, i.e. time. v2 is defined as v2=n−(v1+1).

When F is greater than F crit at 95% confidence (i.e. α = 0.05) with ν1, ν2 degrees of freedom, the null hypothesis is rejected. Hence the correlation between the trend and measured data is statistically significant.

S8

149

150151152

153

154

155156

157

158

159

160

161

162

163164

165166167

168

169

170

171

172

S6 Description of the source region analysis

A Lagrangian particle dispersion model (FLEXPART) was employed to investigate the

source regions of PFOA and PFOS. FLEXPART was run 20 days backward in time for every

measurement sample (i.e., from the sampling location and during the time period of the

measurement) using meteorological input data from the European Centre for Medium Range

Weather Forecasts (ECMWF). The model output consists of an emission sensitivity function S

(in units of s m-3), which is proportional to the particle residence time. We use this emission

sensitivity, the so-called “footprint” (i.e., the emission sensitivity near the surface where

emissions are expected to occur) here for a statistical analysis, similar to that described in

elsewhere (Hirdman et al., 2010; Stohl, 1996).

For this analysis, we calculate the average footprint for all sampling dates,

ST (i , j )= 1M ∑

m=1

M

S (i , j ,m)

M is the total number of samples, and (i, j) refers to grid cells of the regular

latitude/longitude grid of the model output. ST can be considered a flow climatology, where high

values indicate frequent transport to the station, and low values infrequent transport. We, then,

picked the 20% of the data with the highest (80th percentile) measured concentrations for each

component,

SP ( i , j )= 1L∑

l=1

L

S(i , j ,l)

L is the number of samples with the 20% highest concentrations (i.e., L≈M/5). SP is thus

the flow climatology for times when the measured concentrations are high. Both ST and SP have

their highest values at the sampling location, since all air must arrive there. They decrease with

distance from the station; however, depending on prevailing transport patterns, this decrease is

not homogeneous.

S9

173

174

175

176

177

178

179

180

181

182

183

184

185

186

187

188

189

190

191

192

193

194

195

For a clear identification of source areas, we calculate,

RP(i , j)= LM

SP( i , j)ST(i , j)

When using the highest 20% of the data, high Rp values in a grid cell (i, j) indicate that

these data are associated with relatively more frequent transport through this grid cell than for

the whole data set. This, thus, indicates potential source regions of the measured substance.

When using the lowest 20% of the data, high Rp values in a grid cell (i, j) indicate that air

arriving from this grid cell is usually very clean. The analysis works best in the vicinity of the

sampling location, where transport is frequent. For remote regions, transport is infrequent and

particular values may be associated with only a single (or very few) transport events. Thus, Rp

fields become very noisy far away from the sampling station. To eliminate such noise, we plot

Rp(i, j) only if ST(i, j) > T, where T is an appropriately chosen threshold value.

S10

196

197

198

199

200

201

202

203

204

205

206

Table S1. Target and qualifier ions for neutral PFASs analyzed by the GC-MS and allocation of internal (IS) and injection standards (InjS)

Analyte (Abbrev.)

Analyte (Full Name) Target ion

Qualifier ion

IS/InjS

6:2 FTOH 6:2 fluorotelomer alcohol 365 327 13C2-6:2 FTOH8:2 FTOH 8:2 fluorotelomer alcohol 465 427 13C2-8:2 FTOH10:2 FTOH 10:2 fluorotelomer alcohol 565 527 13C2-10:2 FTOH6:2 FTA 6:2 fluorotelomer acrylate 432 461 13C2-6:2 FTOH8:2 FTA 8:2 fluorotelomer acrylate 518 547 13C2-8:2 FTOH10:2 FTA 10:2 fluorotelomer acrylate 618 647 13C2-10:2 FTOHMeFOSA N-methyl perfluorooctane sulfonamide 514 d3-MeFOSAEtFOSA N-ethyl perfluorooctane sulfonamide 528 d5-EtFOSAMeFOSE N-methyl perfluorooctane

sulfonamidoethanol540 558 d7-MeFOSE

EtFOSE N-ethyl perfluorooctane sulfonamidoethanol

554 572 d9-EtFOSE

13C2-6:2 FTOH 2-perfluorohexyl-(13C2)-ethanol 369 331 Me2FOSA (InjS)

13C2-8:2 FTOH 2-perfluorooctyl-(13C2)-ethanol 469 497 Me2FOSA (InjS)

13C2-10:2 FTOH 2-perfluorodecyl-(13C2)-ethanol 569 531 Me2FOSA (InjS)

d3-MeFOSA N-methyl-d3-perfluorooctane sulfonamide 517 Me2FOSA (InjS)

d5-EtFOSA N-ethyl-d5-perfluorooctane sulfonamide 533 Me2FOSA (InjS)

d7-MeFOSE N-methyl-d7-perfluorooctane sulfonamido ethanol

547 565 Me2FOSA (InjS)

d9-EtFOSE N-ethyl-d9-perfluorooctane sulfonamido ethanol

563 581 Me2FOSA (InjS)

Me2FOSA N,N-dimethyl perfluorooctane sulfonamide

528 Me2FOSA (InjS)

S11

207208

209

210

Table S2. Target and qualifier ions for PFAAs analyzed by the LC-MS/MS and allocation of internal (IS) and injection standards (InjS). NA indicates not analyzed.

Analyte (Abbrev.)

Analyte (Full Name) Precursor ion (Q1) m/z

Product ion 1 (Q3) m/z

Product ion 2 (Q3) m/z

IS/InjS used by ECCC

IS/InjS used by NILU

PFBA perfluorobutanoic acid 212.5 168.7 13C4-PFBA NAPFPeA perfluoropentanoic acid 262.5 218.9 13C4-PFBA NAPFHxA perfluorohexanoic acid 312.5 268.9 118.9 13C2-PFHxA 13C2-PFHxAPFHpA perfluoroheptanoic acid 362.5 168.9 318.9 13C2-PFHxA 13C2-PFHpAPFOA perfluorooctanoic acid 412.5 368.9 168.9 13C4-PFOA 13C4-PFOAPFNA perfluorononanoic acid 462.5 418.9 168.9 13C5-PFNA 13C5-PFNAPFDA perfluorodecanoic acid 512.5 468.9 168.9 13C2-PFDA 13C6-PFDAPFUnDA perfluoroundecanoic acid 562.5 518.9 168.9 13C2-PFUnDA 13C7-PFUnDAPFDoDA perfluorododecanoic acid 612.5 568.9 168.9 13C2-PFDoDA NAPFTriDA perfluorotridecanoic acid 662.5 168.9 618.9 13C2-PFDoDA NAPFTeDA perfluorotetradecanoic acid 712.5 168.9 668.9 13C2-PFDoDA NAPFHxDA perfluorohexadecanoic acid 812.5 168.9 768.9 13C2-PFDoDA NAPFODA perfluorooctadecanoic acid 912.5 168.9 868.9 13C2-PFDoDA NAPFBS perfluorobutane sulfonic acid 298.5 79.8 98.9 18O2-PFHxS 13C3-PFHxSPFHxS perfluorohexane sulfonic acid 398.5 79.9 98.9 18O2-PFHxS 13C3-PFHxSPFOS perfluorooctane sulfonic acid 498.5 79.9 98.9 13C4-PFOS 13C4-PFOSPFDS perfluorodecane sulfonic acid 598.5 79.9 98.8 13C4-PFOS 13C4-PFOSPFOSA Perfluorooctane sulfonamide 498.0 78.0 NA 13C8-PFOSA6:2 FTS 6:2 fluorotelomer sulfonic

acid427.0 407.1 80.0 NA 13C2-6:2 FTS

13C3-PFHxS perfluoro-(13C3)-hexane sulfonic acid

402.5 102.9 3,7-dimethyl

PFOA (InjS)13C8-PFOSA perfluoro-(13C8)-octane

sulfonamide506.0 78.0 3,7-dimethyl

PFOA (InjS)13C2-6:2 FTS 6:2 fluorotelomer-(13C2)-

sulfonic acid429.1 409.1 3,7-dimethyl

PFOA (InjS)18O2-PFHxS perfluoro-(18O2)-hexane

sulfonic acid402.5 102.9 13C8-PFOS (InjS)

13C4-PFOS perfluoro-(13C4)-octane sulfonic acid

502.5 79.9 13C8-PFOS (InjS)

13C4-PFBA perfluoro-(13C4)-butanoic acid 216.5 171.7 13C8-PFOA (InjS)13C2-PFHxA perfluoro-(13C2)-hexanoic acid 314.5 269.9 13C8-PFOA (InjS)13C4-PFOA perfluoro-(13C4)-octanoic acid 416.5 371.9 13C8-PFOA (InjS)13C5-PFNA perfluoro-(13C5)-nonanoic acid 467.5 422.9 13C8-PFOA (InjS)13C2-PFDA perfluoro-(13C2)-decanoic acid 514.5 469.9 13C8-PFOA (InjS)13C2-PFUnDA perfluoro-(13C2)-undecanoic

acid564.5 519.9 13C8-PFOA (InjS)

13C2-PFDoDA perfluoro-(13C2)-dodecanoic acid

614.5 569.9 13C8-PFOA (InjS)

13C8-PFOS perfluoro-(13C8)-octane sulfonic acid

506.5 79.9

13C8-PFOA perfluoro-(13C8)-octanoic acid 420.5 375.9

S12

211212

213

214

Table S3 Detection frequency (DF), minimum (min) and maximum (max) concentrations of PFASs in blanks of the Alert samples. We assumed sampling of 2000 m3 when calculating the blank concentration (pg m-3). na = not available.

DF % Min (pg m-3) Max (pg m-3)6:2 FTOH 0 na na8:2 FTOH 52 0.13 1.210:2 FTOH 69 0.025 0.526:2 FTA 2 0.13 0.138:2 FTA 0 na na10:2 FTA 0 na naMeFOSA 93 0.017 0.55EtFOSA 42 0.0083 0.11MeFOSE 64 0.050 0.58EtFOSE 31 0.058 1.1

PFBA 67 0.0087 0.82PFPeA 0 na naPFHxA 0 na naPFHpA 15 0.013 0.034PFOA 54 0.0068 0.16PFNA 3 0.019 0.020PFDA 38 0.0064 0.035PFUnDA 1 0.0067 0.0067PFDoDA 0 na naPFTriDA 0 na naPFTeDA 15 0.0068 0.015PFHxDA 0 na naPFODA 9 0.015 0.030

PFBS 24 0.0063 0.029PFHxS 19 0.0064 0.030PFOS 56 0.0064 0.077PFDS 1 0.0066 0.0066

S13

215216217

218

219

Table S4 Detection frequency (DF), minimum (min) and maximum (max) concentrations of PFASs in the blanks of the Zeppelin and Andøya samples. We assumed sampling of 1200 m3 when calculating the blank concentration (pg m-3). na = not available.

DF % Min (pg m-3) Max (pg m-3)PFOSA 7.7 0.018 0.036

6:2 FTS 3.8 0.074 0.074PFHxA 15 0.019 0.057PFHpA 3.8 0.048 0.048PFOA 27 0.032 0.85PFNA 15 0.012 0.064PFDA 15 0.13 0.52PFUnDA 0 na

nana

PFBS 0 nannanan

naPFHxS 0 na naPFOS 4.0 0.028 0.028PFDS 0 na na

S14

220221222

223

Table S5. Descriptive statistics of PFASs in air at Alert, Zeppelin and Andøya (pg m -3). SD = standard deviation; Max = maximum; Min = minimum. DF = percent of samples above detection limit. Note that when DF is less than 30%, the mean/median is biased towards the DL. BDL = below detection limit, values in parentheses are the estimated DL, which was calculated from averaging the DL over the entire sampling period and for reference only. The summary statistics (i.e. mean, sd, median, max and min) of Sum FTOHs, FTAs, FOSAs and FOSEs were calculated from individual samples.

Analyte Mean SD Median Max Min DF

Alert ( n = 169 ) 6:2 FTOH 0.57 0.82 0.057 3.9 BDL (0.086) 38%8:2 FTOH 3.7 3.5 2.5 21 BDL (0.065) 95%10:2 FTOH 1.3 1.5 0.67 8.7 BDL (0.015) 96%Sum FTOHs 5.5 4.9 3.8 30 BDL6:2 FTA 0.17 0.20 0.080 1.3 BDL (0.120) 32%8:2 FTA 0.09 0.14 0.022 0.71 BDL (0.033) 35%10:2 FTA 0.037 0.039 0.022 0.22 BDL (0.034) 20%Sum FTAs 0.30 0.23 0.24 1.4 BDLMeFOSA 0.17 0.19 0.093 0.64 BDL (0.008) 93%EtFOSA 0.062 0.057 0.044 0.25 BDL (0.006) 81%Sum FOSAs 0.23 0.23 0.13 0.82 BDLMeFOSE 0.41 0.39 0.35 2.7 BDL (0.044) 89%EtFOSE 0.40 0.73 0.099 3.9 BDL (0.056) 60%Sum FOSEs 0.81 0.96 0.49 4.8 BDL

PFBA 3.6 4.9 1.7 29 BDL (0.0063) 99%PFPeA 0.025 0.038 0.0083 0.19 BDL (0.013) 26%PFHxA 0.052 0.068 0.021 0.39 BDL (0.031) 30%PFHpA 0.055 0.082 0.018 0.47 BDL (0.013) 57%PFOA 0.19 0.24 0.097 1.3 BDL (0.0063) 89%PFNA 0.064 0.11 0.022 0.77 BDL (0.013) 54%PFDA 0.054 0.07 0.030 0.46 BDL (0.0063) 87%PFUnDA 0.016 0.027 0.0042 0.14 BDL (0.0063) 32%PFDoDA 0.017 0.029 0.004 0.18 BDL (0.0063) 38%PFTriDA 0.014 0.013 0.0083 0.08 BDL (0.013) 24%PFTeDA 0.012 0.021 0.0042 0.15 BDL (0.0063) 30%PFHxDA 0.0050 0.0063 0.0042 0.077 BDL (0.0063) 6.1%PFODA 0.029 0.043 0.0083 0.20 BDL (0.013) 31%

PFBS 0.066 0.18 0.013 1.5 BDL (0.0063) 66%PFHxS 0.032 0.083 0.0042 0.62 BDL (0.0063) 39%PFOS 0.19 0.42 0.070 2.8 BDL (0.0063) 96%PFDS 0.0047 0.0024 0.0042 0.022 BDL (0.0063) 8.1%

S15

224225226227228229

Analyte Mean SD Median Max Min DFZeppelin (n = 383)PFOSA 0.19 0.31 0.12 4.9 BDL (0.086) 56%

6:2 FTS 0.27 0.25 0.19 2.0 BDL (0.13) 1.1%PFHxA 0.26 0.34 0.15 3.1 BDL (0.089) 8.7%PFHpA 0.38 0.59 0.20 4.9 BDL (0.17) 10%PFOA 0.50 0.54 0.33 4.0 BDL (0.12) 59%PFNA 0.32 0.46 0.19 3.6 BDL (0.079) 19%PFDA 0.54 1.3 0.20 11 BDL (0.085) 11%PFUnDA 0.35 0.59 0.17 4.9 BDL (0.14) 5.9%

PFBS 0.056 0.095 0.028 1.2 BDL (0.026) 1.6%PFHxS 0.036 0.040 0.022 0.35 BDL (0.038) 2.4%PFOS 0.081 0.14 0.050 2.2 BDL (0.037) 50%PFDS 0.033 0.036 0.017 0.21 BDL (0.031) 2.9%

Andøya ( n = 249 ) PFOSA 0.12 0.27 0.072 2.5 BDL (0.11) 9.3%

6:2 FTS 0.66 3.6 0.23 55 BDL (0.24) 4.0%PFHxA 0.32 0.56 0.15 5.3 BDL (0.12) 14%PFHpA 0.44 0.79 0.17 5.1 BDL (0.14) 2.8%PFOA 0.54 0.79 0.24 5.5 BDL (0.12) 48%PFNA 0.50 1.2 0.16 11 BDL (0.072) 21%PFDA 0.79 2.0 0.14 11 BDL (0.051) 18%PFUnDA 0.49 1.0 0.15 6.8 BDL (0.050) 4.4%

PFBS BDL BDL BDL BDL BDL 0%PFHxS BDL BDL BDL BDL BDL 0%PFOS 0.09 0.067 0.072 0.43 BDL (0.043) 48%PFDS 0.043 0.042 0.029 0.29 BDL (0.031) 2.0%

S16

230

231

Table S6. Trend analysis for PFASs in air at Alert that were derived from data above a) IDL b) MDL. t2 indicates doubling time. t1/2 indicates half-life.

Analyte Data above IDL Data above MDLt2 or t1/2? Years t2 or t1/2? Years

8:2 FTOH t2 5.0 t2 5.310:2 FTOH t2 7.0 t2 8.5PFBA t2 2.5 t2 2.3PFBS t2 2.6 t2 2.1PFOA t2 3.7 t2 2.6PFOS t2 2.9 t2 2.8

S17

232233

234

Figure S1. Seasonal cycles and trends of FOSEs and FOSAs in Alert. Measured data are shown with blue crosses, the black line is the seasonal trend, and the pink line is the trend derived from the Digital Filtration technique. Dash pink lines represent the lower and upper 95% confidence limits of the trend. The red line indicates the MDL and the black dash line indicates the IDL.

S18

235236237238

239

Figure S2 Fields of R80 for the highest 20% of all measured PFOSA at Zeppelin

S19

240

241

242

Figure S3 Relative fields of R80 for PFOS and PFOA for the 2013 Alert data to the average of the overall data (2006 to 2014).

S20

243244

245

246

Figure S4. Neutral PFAS vs. inverse temperature in air at Alert

S21

247

248

Figure S5. PFAAs vs. inverse temperature in air at Alert

S22

249

250

Figure S6. PFOSA vs. inverse temperature in air at Zeppelin

S23

251

252

253

Figure S7. PFAAs vs. inverse temperature in air at Zeppelin and Andøya

S24

254

255

256

References

Ahrens, L., Harner, T., Shoeib, M., Koblizkova, M., Reiner, E. J., 2013. Characterization of two

passive air samplers for per- and polyfluoroalkyl substances. Environ. Sci. Technol., 47, 14024-

14033.

Ahrens, L., Shoeib, M., Del Vento, S., Codling, G., Halsall, C., 2011. Polyfluoroalkyl

compounds in the Canadian Arctic atmosphere. Environ. Chem., 8, 399-406.

Dreyer, A., Shoeib, M., Fiedler, S., Barber, J., Harner, T., Schramm, K. W., Jones, K. C.,

Ebinghaus, R., 2010. Field intercomparison on the determination of volatile and semivolatile

polyfluorinated compounds in air. Environ. Chem., 7, 350-358.

Hirdman, D., Sodemann, H., Eckhardt, S., Burkhart, J. F., Jefferson, A., Mefford, T., Quinn, P.

K., Sharma, S., Strom, J., Stohl, A., 2010. Source identification of short-lived air pollutants in

the Arctic using statistical analysis of measurement data and particle dispersion model output.

Atmos. Chem. Phy., 10, 669-693.

Myers, A., Reiner, E., 2017. Northern Contaminants Program and Arctic Monitoring and

Assessment Programme Interlaboratory Study (NCP/AMAP – Phase 10). Ontario Ministry of

Environment and Climate Change. February 28, 2017.

Stohl, A., 1996. Trajectory statistics - a new method to establish source-receptor relationships of

air pollutants and its application to the transport of particulate sulfate in Europe. Atmos.

Environ., 30, 579-587.

S25

257

258

259

260

261

262

263

264

265

266

267

268

269

270

271

272

273

274

275