Supplementary Information
Evaluation of air quality indicators in Alberta, Canada – An
international perspective
Md. Aynul Bari*, Warren B. Kindzierski
School of Public Health, University of Alberta, 3-57 South Academic Building, 11405-87
Avenue, Edmonton, Alberta, T6G 1C9 Canada
38 pages, 4 tables, 27 figures
*Corresponding author. Tel.:+1 780 492 0382; fax: +1 780 492 0364.
Email address: [email protected] (M.A. Bari).
Table S1. Geographic information and location of monitoring stations in Canadian and international urban areas.
Region City Station ID Latitude LongitudeCanadian cities Edmonton 90130 53.54449 -113.49893
Calgary 90228 51.04761 -114.07517Fort McKay 90801 57.18941 -111.6405
Fort McMurray 90701 56.7328 -111.3902Toronto 60433 43.66417 -79.38722Montreal 50109 45.502679 -73.663875
Vancouver 100118 49.26167 -123.16333Ottawa 60104 45.43433 -75.676
Hamilton 60512 43.25778 -79.86167Winnipeg 70118 49.93207 -97.11317Regina 80110 50.45017 -104.61722
Saskatoon 80211 52.13613 -106.66293Halifax 30118 44.646323 -63.573381
U.S. urban areas Denvar 08-031-0025 39.704005 -104.99811Phoenix 04-013-0019 33.48385 -112.14257Chicago 18-089-2004 41.585496 -87.474486Boston 25-025-0042 42.3295 -71.0826
Pittsburg 42-003-0064 40.323768 -79.868062Milwaukee 55-079-0026 43.060975 -87.913504Houston 48-201-1035 29.733726 -95.257593
EU urban areas Prague CZ0ARIE 14.442692 50.081482Brussels BETR001 4.332555 50.850208
Berlin DEBE068 13.418833 52.513606Zurich CH0010A 8.530419 47.377586Sofia BG0050A 23.296786 42.680558
Madrid ES0126A -3.73194 40.39472Paris FR04143 2.351111 48.85944
London GB0566A -0.12589 51.52229Australia Sydney Earlwood 33.917778 151.134722
Table S2. Measurement methods used in Canadian and international urban areas.
NO2 SO2 PM2.5 O3Canadian cities Edmonton Gas Phase Chemiluminescence Pulsed Fluorescence TEOM-FDMS Ultraviolet Absorption
Calgary Gas Phase Chemiluminescence Pulsed Fluorescence TEOM-FDMS Ultraviolet AbsorptionFort McKay Gas Phase Chemiluminescence Pulsed Fluorescence SHARP 5030 Ultraviolet AbsorptionFort McMurray Gas Phase Chemiluminescence Pulsed Fluorescence SHARP 5030 Ultraviolet AbsorptionToronto Gas Phase Chemiluminescence Pulsed Fluorescence TEOM-SES Ultraviolet AbsorptionMontreal Gas Phase Chemiluminescence Pulsed Fluorescence TEOM-FDMS Ultraviolet AbsorptionVancouver Gas Phase Chemiluminescence Pulsed Fluorescence TEOM-SES Ultraviolet AbsorptionOttawa Gas Phase Chemiluminescence Pulsed Fluorescence TEOM-SES Ultraviolet AbsorptionHamilton Gas Phase Chemiluminescence Pulsed Fluorescence TEOM-SES Ultraviolet AbsorptionWinnipeg Gas Phase Chemiluminescence Pulsed Fluorescence SHARP 5030 Ultraviolet AbsorptionRegina Gas Phase Chemiluminescence Pulsed Fluorescence BAM Ultraviolet AbsorptionSaskatoon Gas Phase Chemiluminescence Pulsed Fluorescence TEOM Ultraviolet AbsorptionHalifax Gas Phase Chemiluminescence Pulsed Fluorescence BAM Ultraviolet Absorption
U.S. urban areas Denver Gas Phase Chemiluminescence1 Ultraviolet Fluorescence R & P Model 2025 PM2.5 Sequential w/WINS Ultraviolet Absorption2
Phoenix Gas Phase Chemiluminescence1 Ultraviolet Fluorescence R & P Model 2025 PM2.5 Sequential w/WINS Ultraviolet Absorption2
Chicago Gas Phase Chemiluminescence1 Ultraviolet Fluorescence R & P Model 2025 PM2.5 Sequential w/WINS Ultraviolet Absorption2
Boston Gas Phase Chemiluminescence1 Multiple Methods Used R & P Model 2025 PM2.5 Sequential w/WINS Ultraviolet Absorption2
Pittsburgh Gas Phase Chemiluminescence1 Ultraviolet Fluorescence R & P Model 2025 PM2.5 Sequential w/WINS Ultraviolet Absorption2
Milwaukee Gas Phase Chemiluminescence1 Ultraviolet Fluorescence R & P Model 2025 PM2.5 Sequential w/WINS Ultraviolet Absorption2
Houston Gas Phase Chemiluminescence1 Ultraviolet Fluorescence R & P Model 2025 PM2.5 Sequential w/WINS Ultraviolet Absorption2
EU urban areas Prague Chemiluminescence Ultraviolet Fluorescence BAM Ultraviolet AbsorptionBrussels Chemiluminescence Ultraviolet Fluorescence Rupprecht & Patashnick TEOM 1400a Ultraviolet AbsorptionBerlin Chemiluminescence Ultraviolet Fluorescence Gravimetry Ultraviolet AbsorptionZurich Chemiluminescence Ultraviolet Fluorescence Gravimetry (Digitel HIVOL) Ultraviolet AbsorptionSofia Chemiluminescence Ultraviolet Fluorescence Beta-absorption Ultraviolet AbsorptionMadrid Chemiluminescence Ultraviolet Fluorescence Gravimetry Ultraviolet AbsorptionParis Chemiluminescence Ultraviolet Fluorescence TEOM Ultraviolet AbsorptionLondon Chemiluminescence Ultraviolet Fluorescence TEOM-FDMS Ultraviolet Absorption
Australia Sydney Chemiluminescence Pulsed fluorescent spectrophotometry BAM Ultraviolet Spectroscopy
1Federal Reference Method, 2Federeal Equivalent Method, TEOM-FDMS: Tapered Element Oscillating Microbalances-Filter Dynamics Measurement Systems, SHARP 5030: Synchronized Hybrid Ambient Real-time, TEOM-SES: Tapered Element Oscillating Microbalances-Sample Equilibration System, BAM: Beta Attenuation Monitor.
Fig. S1a. Location of Edmonton Central and East air monitoring stations (yellow stick pins) and industries in and surrounding Edmontonthat report to Environment Canada’s National Pollutant Release Inventory (NPRI) during 2013 using Google Earth; note: red bar = 15 km(Image IBCAO © 2016 Google).
Fig. S1b. Location of Calgary Central and East air monitoring stations (yellow stick pins) and industries in and surrounding Calgary thatreport to Environment Canada’s National Pollutant Release Inventory (NPRI) during 2013 using Google Earth; note: red bar = 15 km(Image IBCAO © 2016 Google).
Fig. S1c. Location of Fort McKay air monitoring station (yellow stick pin) and industries in and surrounding Fort McKay that report to Environment Canada’s National Pollutant Release Inventory (NPRI) during 2013 using Google Earth; note: red bar = 15 km (Image IBCAO © 2016 Google).
Fig. S1d. Location of Fort McMurray Athabasca Valley air monitoring station (yellow stick pin) and industries in and surrounding Fort McMurray that report to Environment Canada’s National Pollutant Release Inventory (NPRI) during 2013 using Google Earth; note: red bar = 15 km (Image IBCAO © 2016 Google).
Fig. S2. Temporal profiles of hourly concentrations of NO2 at four communities of Alberta for 1998–2014. Boxes represent 25th (lower quartile) and 75th
(upper quartile) percentile values, with median values as lines across the boxes, geometric mean values as round black ball and 10 th and 98th percentile concentrations as whiskers.
Fig. S3. Temporal profiles of hourly concentrations of SO2 at four communities of Alberta for 1998–2014. Boxes represent 25th (lower quartile) and 75th (upper quartile) percentile values, with median values as lines across the boxes, geometric mean values as round black ball and 10 th and 98th percentile concentrations as whiskers.
Fig. S4. Temporal profiles of hourly concentrations of PM2.5 at four communities of Alberta for 1998–2014. Boxes represent 25th (lower quartile) and 75th (upper quartile) percentile values, with median values as lines across the boxes, geometric mean values as round black ball and 10 th and 98th percentile concentrations as whiskers.
Fig. S5. Temporal profiles of hourly concentrations of O3 at four communities of Alberta for 1998–2014. Boxes represent 25th (lower quartile) and 75th (upper quartile) percentile values, with median values as lines across the boxes, geometric mean values as round black ball and 10 th and 98th percentile concentrations as whiskers.
Fig. S6. Temporal profiles of hourly concentrations of THC at four communities of Alberta for 1998–2014. Boxes represent 25th (lower quartile) and 75th (upper quartile) percentile values, with median values as lines across the boxes, geometric mean values as round black ball and 10 th and 98th percentile concentrations as whiskers.
Fig. S7. Temporal profiles of hourly concentrations of CO at four communities of Alberta for 1998–2014. Boxes represent 25th (lower quartile) and 75th (upper quartile) percentile values, with median values as lines across the boxes, geometric mean values as round black ball and 10 th and 98th percentile concentrations as whiskers.
Fig. S8. Theil-Sen’s trend plots for annual geometric mean concentrations of NO2 at four communities of Alberta (1998–2014).
Edmonton central NO2
Edmonton east NO2
Calgary central NO2
Calgary east NO2
Fort McKay NO2
Fort McMurray NO2
Fig. S9. Theil-Sen’s trend plots for annual geometric mean concentrations of SO2 at four communities of Alberta (1998–2014).
Edmonton east SO2
Calgary east SO2
Fort McKay SO2
Fort McMurray SO2
Fig. S10. Theil-Sen’s trend plots for annual geometric mean concentrations of PM2.5 at four communities of Alberta (1998–2014).
Edmonton central PM2.5
Edmonton east PM2.5
Calgary central PM2.5
Calgary east PM2.5
Fort McKay PM2.5
Fort McMurray PM2.5
Fig. S11. Theil-Sen’s trend plots for annual geometric mean concentrations of O3 at four communities of Alberta (1998–2014).
Edmonton central O3
Edmonton east O3
Calgary central O3
Calgary east O3
Fort McKay O3
Fort McMurray O3
Fig. S12. Theil-Sen’s trend plots for annual geometric mean concentrations of THC at four communities of Alberta (1998–2014).
Edmonton central THC
Edmonton east THC
Calgary central THC
Calgary east THC
Fort McKay THC
Fort McMurray THC
Fig. S13. Theil-Sen’s trend plots for annual geometric mean concentrations of CO at four communities of Alberta (1998–2014).
Edmonton central CO
Edmonton east CO
Calgary central CO
Calgary east CO Fort McMurray CO
0 6 12 18 24
0
10
20
30
40
50
Time (h)
Con
cent
ratio
n (p
pb)
0 6 12 18 240
10
20
30
40
50
Time (h)
Con
cent
ratio
n (p
pb)
Fig. S14. Average diurnal (hourly) concentrations of NO2 and O3 at the major urban cities in Alberta for the period of 1998–2014 (missing data at 2:00 due to automatic instrument calibration).
Winter
Summer
1998–2014
1998–2014
NO2_Fort McMurray
NO2_Edmonton central
NO2_Calgary central
NO2_Fort McKayO3_Fort McKay
O3_Edmonton central
O3_Calgary central
O3_Fort McMurray
O3_Edmonton central
O3_Calgary central O3_Fort McKay
O3_Fort McMurray
NO2_Fort McMurray
NO2_Fort McKay
NO2_Edmonton central
NO2_Calgary central
0 6 12 18 240
10
20
30
Time (h)
PM
2.5
(µg/
m3)
0 6 12 18 240
10
20
30
Time (h)
PM
2.5
(µg/
m3)
PM2.5
PM2.5
Winter
Winter
Summer
SummerSO2 SO2
Calgary central
Edmonton centralFort McKay
Fort McMurrayFort McMurrayFort McKay
Edmonton centralCalgary central
1998–2014 1998–2014
Calgary east
Calgary eastEdmonton eastEdmonton east
Fort McKay
Fort McKay
Fort McMurrayFort McMurray
0 6 12 18 240
1
2
3
4
5
Time (h)
SO
2 (p
pb)
0 6 12 18 240
1
2
3
4
5
Time (h)
SO
2 (p
pb)
Fig. S15. Average diurnal (hourly) concentrations of PM2.5 and SO2 (missing data for SO2 at 2:00 due to automatic instrument calibration).
0 6 12 18 241.0
1.5
2.0
2.5
3.0
Time (h)
THC
(ppm
)
0 6 12 18 240
1
2
3
4
Time (h)
THC
(ppm
)
0 6 12 18 240.0
0.5
1.0
1.5
2.0
Time (h)
CO
(ppm
)
0 6 12 18 240.0
0.5
1.0
1.5
2.0
Time (h)
CO
(ppm
)
Winter 1998–2014 THC THC1998–2014 Summer
CO COWinter Summer
Edmonton central
Edmonton central
Calgary central
Calgary central
Fort McMurray
Fort McMurray
Edmonton centralCalgary central
Fort McMurray
Fort McKay
Fig. S16. Average diurnal (hourly) concentrations of THC and CO (missing data for SO2 at 2:00 due to automatic instrument calibration).
Fig. S17. Box plots of monthly NO2 concentrations over the period 1998–2014. Boxes represent 25th (lower quartile) and 75th (upper quartile)
percentile values, with median values as lines across the boxes, mean values as round black ball and minimum and maximum values as whiskers.
Fig. S18. Box plots of monthly O3 concentrations over the period 1998–2014. Boxes represent 25th (lower quartile) and 75th (upper quartile)
percentile values, with median values as lines across the boxes, mean values as round black ball and minimum and maximum values as whiskers.
Fig. S19. Box plots of monthly PM2.5 concentrations over the period 1998–2014. Boxes represent 25th (lower quartile) and 75th (upper quartile)
percentile values, with median values as lines across the boxes, mean values as round black ball and minimum and maximum values as whiskers.
Fig. S20. Box plots of monthly SO2 concentrations over the period 1998–2014. Boxes represent 25th (lower quartile) and 75th (upper quartile)
percentile values, with median values as lines across the boxes, mean values as round black ball and minimum and maximum values as whiskers.
Fig. S21. Box plots of monthly CO concentrations over the period 1998–2014. Boxes represent 25th (lower quartile) and 75th (upper quartile)
percentile values, with median values as lines across the boxes, mean values as round black ball and minimum and maximum values as whiskers.
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
0
5
10
15
20
1 1
8
1
Number of 8 h O3 exceedances (> 65 ppb)Edmonton centralCalgary centralFort McKayFort McMurray
No
of O
3 ex
ceed
ance
s
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
0
10
20
30
40
50
10
1 1
12
52
12
31 2
73
1 1 2 2 2
21
8
2
84
1 25
2 31 1
18
52
10
13 2
41 1 2
32
73
52
Number of 24 h PM2.5 exceedances (> 30 μg/m3)Edmonton centralCalgary centralFort McKayFort McMurray
No.
of P
M2.
5 ex
ceed
ance
s
a
b
Fig. S22. Total number of exceedances of Canada-Wide Standard for (a) 8 h O3 (65 ppb) and (b) 24 h PM2.5 (30 μg/m3) concentrations at the
community stations over the study period (1998–2014).
1-Ja
n-98
1-Ju
l-98
1-Ja
n-99
1-Ju
l-99
1-Ja
n-00
1-Ju
l-00
1-Ja
n-01
1-Ju
l-01
1-Ja
n-02
1-Ju
l-02
1-Ja
n-03
1-Ju
l-03
1-Ja
n-04
1-Ju
l-04
1-Ja
n-05
1-Ju
l-05
1-Ja
n-06
1-Ju
l-06
1-Ja
n-07
1-Ju
l-07
1-Ja
n-08
1-Ju
l-08
1-Ja
n-09
1-Ju
l-09
1-Ja
n-10
1-Ju
l-10
1-Ja
n-11
1-Ju
l-11
1-Ja
n-12
1-Ju
l-12
1-Ja
n-13
1-Ju
l-13
1-Ja
n-14
1-Ju
l-14
0
30
60
90
120
150
180
24 h PM2.5Edmonton central
μg/m
3
1-Ja
n-98
1-Ju
l-98
1-Ja
n-99
1-Ju
l-99
1-Ja
n-00
1-Ju
l-00
1-Ja
n-01
1-Ju
l-01
1-Ja
n-02
1-Ju
l-02
1-Ja
n-03
1-Ju
l-03
1-Ja
n-04
1-Ju
l-04
1-Ja
n-05
1-Ju
l-05
1-Ja
n-06
1-Ju
l-06
1-Ja
n-07
1-Ju
l-07
1-Ja
n-08
1-Ju
l-08
1-Ja
n-09
1-Ju
l-09
1-Ja
n-10
1-Ju
l-10
1-Ja
n-11
1-Ju
l-11
1-Ja
n-12
1-Ju
l-12
1-Ja
n-13
1-Ju
l-13
1-Ja
n-14
1-Ju
l-14
0
30
60
90
120
150
18024 h PM2.5Calgary central
μg/m
3
Fig. S23. PM2.5 concentrations (24 h) at Edmonton and Calgary central sites over the study period (1998–2014).
24 h Canada-Wide Standard
24 h Canada-Wide Standard
1-Ja
n-98
1-Ju
l-98
1-Ja
n-99
1-Ju
l-99
1-Ja
n-00
1-Ju
l-00
1-Ja
n-01
1-Ju
l-01
1-Ja
n-02
1-Ju
l-02
1-Ja
n-03
1-Ju
l-03
1-Ja
n-04
1-Ju
l-04
1-Ja
n-05
1-Ju
l-05
1-Ja
n-06
1-Ju
l-06
1-Ja
n-07
1-Ju
l-07
1-Ja
n-08
1-Ju
l-08
1-Ja
n-09
1-Ju
l-09
1-Ja
n-10
1-Ju
l-10
1-Ja
n-11
1-Ju
l-11
1-Ja
n-12
1-Ju
l-12
1-Ja
n-13
1-Ju
l-13
1-Ja
n-14
1-Ju
l-14
0
30
60
90
120
150
18024-h PM2.5Fort McKay
Fort McMurray
μg/m
3
Fig. S24. PM2.5 concentrations (24 h) in the AOSR over the study period (1998–2014).
24 h Canada-Wide Standard
1-Ja
n-11
11-J
an-1
121
-Jan
-11
31-J
an-1
110
-Feb
-11
20-F
eb-1
12-
Mar
-11
12-M
ar-1
122
-Mar
-11
1-A
pr-1
111
-Apr
-11
21-A
pr-1
11-
May
-11
11-M
ay-1
121
-May
-11
31-M
ay-1
110
-Jun
-11
20-J
un-1
130
-Jun
-11
10-J
ul-1
120
-Jul
-11
30-J
ul-1
19-
Aug
-11
19-A
ug-1
129
-Aug
-11
8-S
ep-1
118
-Sep
-11
28-S
ep-1
18-
Oct
-11
18-O
ct-1
128
-Oct
-11
7-N
ov-1
117
-Nov
-11
27-N
ov-1
17-
Dec
-11
17-D
ec-1
127
-Dec
-110
100
200
300
400
5001 h PM2.5Fort McKay
Fort McMurray
μg/m
3
Fig. S25. MODIS satellite image of wildfires on May 16, 2011 in Slave Lake, Alberta (a) and
impact on ambient PM2.5 concentrations in the AOSR (b).
May 16, 2011
Slave Lake
1 h AAAQO of 80 μg/m3
a
b
Fort McMurray
Fig. S26. Comparison of 1 h percentile concentrations between Canadian and major U.S. cities during 2012 using box-whisker plots; data for
Edmonton/Calgary are based on central stations except east stations for SO2.
0
10
20
30
40
50
60PM2.5Edmonton Downtown Calgary Downtown
Fort McKay Fort McMurrayToronto Downtown Montreal DowntownOttawa Downtown
98th
Per
cent
le P
M2.
5 (μ
g/m
3)
Fig. S27. Comparison of 98th percentile concentrations of PM2.5 between major Canadian cities over the period of 2003 to 2013
excluding year 2010 for Edmonton and 2011 for Fort McKay and Fort McMurray due to extreme wildfires impact.
24 h Canada-Wide Standard
Industrial emission trends
The National Pollutant Release Inventory (NPRI) reports annual releases of pollutants to air from
Canadian industrial facilities/operations (Environment Canada, 2015). Annual reported emissions of NOX,
SO2, and PM2.5 releases to air from industrial facilities/operations in Edmonton, Calgary and the
Athabasca Oil Sands Region (AOSR) were accessed from Environment Canada (2015) for the latest 12
years available (2003–2014) and are summarized in Table S3. NPRI quantities do not account for small
emission sources, such as small compressors and generators, and emissions from private/commercial
vehicles. Table S4 shows trends in NPRI reported industrial emissions for NOX, SO2, and PM2.5 using the
non-parametric (Mann-Kendall and Theil-Sen) approach.
Table S3. Reported NPRI emissions for NOX, SO2, and PM2.5 in Edmonton, Calgary and the Athabasca
Oil Sands Region (AOSR) for the period 2002–2014 (Environment Canada, 2015).
Edmonton CalgaryAthabasca Oil Sands Region
(AOSR)1
Year NOx SO2 PM2.5 NOx SO2 PM2.5 NOx SO2 PM2.5
tonnes tonnes tonnes tonnes tonnes tonnes tonnes tonnes tonnes2002 – – – – – – 21,222 103,792 6242003 75,443 86,489 3,047 8,756 17,858 187 21,194 96,935 1,2152004 76,918 85,698 3,176 5,649 17,648 158 23,868 103,707 1,1662005 75,463 86,968 2,487 5,813 18,085 182 24,376 110,712 1,4412006 73,689 82,277 2,578 5,519 16,131 166 26,551 106,380 2,5322007 72,598 80,453 2,880 5,747 13,930 250 27,943 111,770 3,3962008 72,888 83,455 2,980 5,204 13,449 169 25,006 100,460 2,3862009 72,912 82,588 2,848 4,710 12,179 163 28,032 101,612 2,1512010 73,414 84,343 2,683 4,578 13,939 144 30,075 98,641 2,6262011 64,174 75,503 2,476 4,679 9,229 187 32,685 87,478 2,6532012 59,966 69,131 2,381 4,779 9,852 173 30,246 94,498 2,7262013 61,064 72,594 2,496 4,896 8,910 174 28,027 81,808 2,650
2014 71,234 84,702 3,290 4,250 9,035 168 29,039 45,762 3,9311Reported available NPRI emissions from oil sands and heavy oil facilities within 70-km around Fort McKay; –, not available.
Note: Methods used for quantifying annual releases of substances that are reported in NPRI can vary. Gases like NO x, and SO2 are based on continuous emission monitoring systems (CEMS), while PM2.5 is based on a combination of manual stack testing (Environment Canada, 2015). Environment Canada implements quality measures in an attempt to ensure that NPRI data maintains a high standard of accuracy, consistency and comprehensiveness. Facilities that meet NPRI reporting requirements are required to submit information that is true, accurate, and complete to the best of their knowledge and the Canadian Environmental Protection Act, 1999 sets out penalties for facilities that fail to report or that knowingly submit false or misleading information.
At Edmonton and Calgary, statistically significant downward trends for industrial emissions were
observed for NOX (p = 0.01) with annual decreases of –933 and –164 tonnes/year (–1.2% and –2.7% per
year), respectively over the 2003–2014 period. In contrast, in the AOSR a small upward trend was
Table S4. Reported NPRI emission trends for NOX, SO2, and PM2.5 in Edmonton, Calgary and the
Athabasca Oil Sands Region (AOSR) for the period 2002–2014.
Edmonton Calgary AOSR
Unit T ∆R% ∆R p-value T ∆R % ∆R p-value T ∆R
% ∆R p-value
NOX tonnes ▼ –933 –1.2 ** ▼ –164 –2.7 ** ▲ 750 3.3 **SO2 tonnes ▼ –1204 –1.4 + ▼ –906 –5.0 *** ▼ –2634 –2.3 *PM2.5 tonnes ▬ –37 –1.3 0.152 ▬ –1 –0.6 0.392 ▲ 176 16.7 **
T: Direction of trend: ▬ no change; ▲ increasing; ▼ decreasing; ∆R = rate of change (unit per year).***p ≤ 0.001. **p ≤ 0.01.*p ≤ 0.05. +p ≤ 0.1.
observed for industrial NOx emissions with an annual increase of 750 tonnes/year (3.3% per year) over
the 2002–2014 period, suggesting an influence of emissions from oil sands development activities. SO 2
represents the best marker for emissions of activities involving combustion of fossil fuels. However,
statistically significant downward trends were observed for SO2 emissions at Edmonton, Calgary and the
AOSR with annual decreases ranging from –2634 to –906 tonnes/year (–5.0% to –1.4% per year). Small
non-significant downward trends with annual decreases of –37 tonnes/year (–1.3% per year, p = 0.152)
and 1.0 tonnes/year (–0.6% per year, p = 0.392) were observed for industrial PM2.5 emissions at
Edmonton and Calgary, respectively. While at the AOSR, non-parametric approach suggested significant
upward trend (p ≤ 0.01) for PM2.5 emissions with an annual increase of 176 tonnes/year.
Environment Canada (2015) provides guidance in preparing NPRI emission estimates and emission
factors are typically based on or are similar to those published by U.S. Environmental Protection Agency
for the Toxics Release Inventory (TRI) Program. TRI data are self-reported by facilities according to
guidance provided by U.S. EPA (2016). While Environment Canada (2015) implements quality measures
in an attempt to ensure that NPRI data maintains a high standard of accuracy, consistency and
comprehensiveness, the extent of errors in reported versus actual emission quantities of NOX, SO2, and
PM2.5 in Table S3 is unknown and may well be above the %-change-per-year quantities in the table. It is
note that emission information is absent for transportation sector emissions in urban areas in Alberta. The
transportation sector accounts for an important fraction of key air pollutant emissions including PM2.5, and
secondary nitrate precursor (NOX) and secondary organic aerosol precursor (VOC) emissions to urban
areas (Fine et al., 2004; Zhang et al., 2004; Wang et al., 2009; Gordon et al., 2014). Over a 13-year period
the City of Edmonton population increased from 657,350 (2001) to 877,926 (2014) or ~17,000 more
people each year over the period (City of Edmonton, 2015). In addition, over a 10-year period motor
vehicle registrations in Edmonton and the adjacent City of St Albert (current population ~64,000)
increased from 502,200 registrations (2004) to 708,500 registrations (2014) or ~20,600 more vehicles
using Edmonton and St Albert roadways each year over this period (Alberta Transportation, 2008, 2012,
2014). Over the 10-year period 2004-2014 the city added 261,700 residents to its population (City of
Calgary, 2015) and 26,170 more registered vehicles each year (average) using its roadways (Alberta
Transportation, 2015). These surrogate data suggest an increasingly important role of transportation
sector emissions in Edmonton and Calgary over the past decade; whereas NPRI-reported industrial
emissions trends for PM2.5 and major trace elements in Edmonton and Calgary (Table S4) may have
decreased or remained unchanged over this time.
It is acknowledged that only trends for NPRI reported available annual industrial emissions of NOX, SO2,
and PM2.5 over the 2002–2014 period are investigated. It is noteworthy that no emission inventory data is
available on other potentially important emission sources in the Alberta e.g., automobile emissions and
small-scale wood combustion and this warrants additional investigation.
References
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