Part of Air

Air indicators – Wildfire smoke

Air monitoring results for impacts related to wildfire smoke.

About the indicator

When wildfires burn trees and other plant material, they emit smoke, which is a complex mixture of gases and particles. The smoke is then transported over short and long distances, including across provincial and federal borders. Wildfire smoke can often impact large areas hundreds of square kilometres in size for extended periods of time (days or weeks).

Wildfire smoke is a major contributor to poor air quality and can have far-reaching impacts on both the environment and human health. The smoke generated by a wildfire contains a mixture of pollutants, including particulate matter, carbon monoxide, nitrogen oxides, and volatile organic compounds (VOCs), which can be harmful when inhaled.

This indicator provides information on wildfire prevalence (estimated area burned between 1990 and 2021) and wildfire smoke impacts on air quality (the number of days a long-term air quality monitoring station is impacted by wildfire smoke between 2015 and 2021).

Wildfire smoke facts

  • Wildfire season varies across different jurisdictions. In Alberta, the official wildfire season is set provincially and runs from March 1 to October 31. Due to Alberta experiencing warmer than normal temperatures and below average precipitation, wildfire season in 2024 was declared on February 20, 2024.
  • One of the primary health impacts of wildfire smoke is its effect on respiratory health. Fine particulate matter (PM2.5) — particles that are less than 2.5 micrometers (µm) in diameter — within smoke can penetrate deep into the lungs and cause irritation making it difficult to breathe. This makes those with pre-existing medical conditions, especially underlying heart and/or lung problems, particularly vulnerable.
    • Other pollutants that are in, or created by, wildfire smoke include nitrogen dioxide (NO2), ozone (O3), sulphur dioxide (SO2), and polycyclic aromatic hydrocarbons (PAHs), among others.
    • The type and concentration of pollutants in wildfire smoke depend on many factors including the distance that smoke has travelled, the type of vegetation burned and the age of the smoke.
    • Wildfire smoke can reduce visibility, irritate the eyes, cause strong odour, and can have significant impacts on outdoor activities. Smoke can also affect indoor air quality.
  • Wildfires can be caused by both natural events (for example lightning) and human activity (for example campfires, fireworks, off-highway vehicles, incendiary, industrial activity).
  • Recorded wildfires vary dramatically in size with some being less than 100 m2 to some being over 1,000 km2 (which is approximately the size of Calgary or Edmonton).
  • Area burned by wildfires are increasing in some areas most likely due to increasing global temperatures and increased human activity (IPCC, 2022). This can result in an increase in poor air quality from wildfire smoke.
    • The extent of burned area in a given year is influenced by the presence of long-term drought, high winds, timing and location of precipitation, extreme weather events, among other factors.
  • Wildfire smoke experienced by Albertans most often originates from fires burning in Alberta, British Columbia (B.C.), and the northwestern United States (U.S.) due to predominant wind directions.

For more information on wildfire smoke and air quality in Alberta, see the wildfire smoke information page.

Methods

For information on how the results in this indicator were calculated and for references, see: Condition of the Environment Report – Air Component

Summary of key results

Last updated: April 2024

  • The total estimated area burned by wildfires in Alberta has increased in recent decades (1990-1999: 1,494,851 ha; 2000-2009: 1,976,752 ha; 2010-2019: 4,572,708 ha) and wildfires are becoming more prevalent in spring months.
  • Effects of wildfires and wildfire smoke differ across regions depending on the time of year.
  • In 2021, northern regions in Alberta observed more wildfire smoke impacts in May, while southern regions observed more impacts from smoke in August.

Variation across Alberta

  • In 2021, wildfire smoke from fires in B.C. and the northwestern U.S. throughout July and August, as well as smoke from wildfires in Saskatchewan in early October, affected much of the province.
  • Wildfire smoke impacts on air quality vary across the province depending on the location and extent of wildfires. One of the major components of smoke that poses a risk to human health is PM2.5. Figure 1 shows the number of days affected by wildfire smoke with elevated PM2.5 concentrations (daily average PM2.5 > 15 µg/m3) for select monitoring stations in the province in 2021.
    • In general, stations in southern Alberta were affected more frequently by wildfire smoke than those in northern Alberta.
    • The station most affected by wildfire smoke in 2021 was the Tomahawk station to the west of Edmonton which was impacted for a total of 36 days. A fire in close proximity to the monitoring station frequently affected air quality from May to October. Other stations in Alberta saw limited effects from this fire.
  • The areas of the province that are impacted by wildfire smoke change from year to year.
    • In 2019, wildfires were burning in northern Alberta (near the communities of High Level and Slave Lake) starting in late-May, followed by wildfires in northeastern Alberta in mid-to-late July. Smoke from these wildfires primarily affected northern Alberta, but was transported throughout Alberta in late-May and early-June.
    • In 2020, smoke from wildfires burning in the northwestern U. S. travelled to Alberta, primarily affecting central and southern Alberta throughout September.

Figure 1. Number of days that a station was impacted by wildfire smoke in Alberta in 2021. Circles represent current long-term continuous air quality monitoring stations.

 

Select a circle on the map to view the number of days in 2021 that were impacted by wildfire smoke for a specific monitoring station.

Source: Government of Alberta

Changes over time

Wildfire prevalence

  • Figure 2 shows the total estimated area burned (in hectares) for northwestern Canadian provinces and territories as well as western U.S. states. Due to the random occurrence of megafires (greater than 40,500 ha) that can occur for a variety of reasons, it is difficult to identify trends in the data.
    • It is not clear whether the annual total area burned in these regions has increased over the last 20 years.
  • The area burned in Alberta and neighbouring provinces and territories that impact Alberta, is often greater than the area burned in western U.S. states (Figure 2). This could be due to several factors, such as differences in region total area, population, fire prevention practices, among others.
    • 2020 is notable for a small total area burned across Alberta and neighbouring Canadian provinces, attributed to many factors including substantial precipitation (CIFFC, 2020).
    • However, 2020 was a very active fire season in the western U.S. with area burned in California being the highest over the past 20 years.
  • In 2023, (not shown here), wildfires burned more area in Alberta than in any previously recorded year. For more information on wildfires in Alberta see the Alberta Wildfire page.

Figure 2. Stacked bar plot showing the total area burned (in hectares) by year from 1990 to 2021.

Chart data table
Year Alberta British Columbia Saskatchewan Northwest Territories Yukon Territory Oregon Washington California Idaho Montana
1990 58885.2 6714.5 216055.6782 104617.4 182891.92
1991 6714.5 25188.8 198175.11 225466.42 120270.82
1992 3561.3 30452.8 97756.39 36949.45 37815.07
1993 27692.21 5183.4 608199.84 864285.83 115104.31
1994 96726.73 29755.3 846019.45 3027314.55 421710.39
1995 341979.36 48080 1648808.89 2843366.44 261882.24
1996 15597.09 20669.1 12986.99 371544.72 91067.13 6
1997 4923.95 2967.8 3876.91 126531.27 11470.05
1998 748776.27 76767.344 1044696.22 1458960.16 343731.4
1999 189995.27 11555.41 180820.24 561034.64 194816.48
2000 25251.58 17808.712 141423.11 177835.79 8015.86
2001 166987.109 14173.209 205133.72 116761.72 17334.48
2002 500554.42 8586.56 882656.32 27089.17 58885.2 449005.3723 44478.36748 242486.988 56221.17773 55472.5063
2003 204345.72 283402.812 126089.25 127821.4 48785.33 106302.0357 89940.93438 365130.2953 157709.8631 325535.6937
2004 432325.59 220296.467 258138.61 517356.03 1719664.09 68837.30309 51242.31036 133378.4462 34818.48256 26051.33774
2005 92368.951 36832.976 214918.41 27692.21 187438.34 117013.7028 81122.39428 125622.2102 242472.0146 69936.83838
2006 136311.83 139424.452 1208434.56 61397.03 95033.34 267829.7184 180100.8046 311736.2628 419403.7132 448255.4868
2007 325994.31 29986.854 213072.22 445129.38 38357.76 307126.0655 101053.6466 469557.4149 901463.941 348021.7366
2008 36535.24 15300.93 1130320.29 308788.75 13067.88 102252.7349 62470.7631 604076.6745 91391.33352 85554.52916
2009 94558.47 247519.784 43808.52 10337.05 230512.35 93613.06659 41953.52366 202151.404 22895.58648 35347.40881
2010 86952.69 337180.849 1735336.12 350926.99 146963.27 84355.84549 31283.13465 73691.1221 275045.2922 39752.02496
2011 892232.28 13153.027 344087.39 329684.8246 40464.33 145512.1844 14627.01636 75323.22583 172977.9041 84031.28631
2012 652084.451 103218.771 228956.32 304535.36 58280.7 532927.3931 108761.7248 374914.0145 687449.5346 505555.1561
2013 55732.75 18836.3402 369758.53 555059.22 198313.79 172182.2889 67076.10413 253422.8519 303959.7924 64519.29002
2014 288049.241 368927.9871 345208.48 3421312.52 3160.594 434437.845 162752.6711 239591.046 94877.30959 34790.55914
2015 843873.109 280957.772 1769027.95 722106.64 169842.61 313139.7182 463256.0295 380483.3206 336036.9234 160324.9522
2016 515165.2902 100446.811 255789.42 255523.86 21537.4 123005.0977 122675.6822 245955.9672 163223.727 59528.68672
2017 149769.4636 1229860.182 399797.404 1033076.81 399280.15 308613.2912 165694.7475 532465.6449 291001.3016 562789.6707
2018 85017.5051 1360935.272 192732.91 22176.74 80585.49 363110.7844 177590.4081 737806.8749 244625.7602 39584.07975
2019 1003831.253 21544.364 48153.7 105167.37 256066.62 32266.52469 68692.02037 104873.8943 114941.704 26237.89857
2020 4798.0233 14671.463 42952.111 21139.03 3463.92 461996.0357 340896.489 1656041.177 127214.2499 149585.7663
2021 54088 869255 956084 156630 118126 335395.8988 272849.0545 903936.1755 177900.5199 302575.7619

Canadian regions are shaded in blue and U.S. regions are shaded in red, orange and yellow. U.S. data from the National Interagency Fire Center is only available from 2002 onward.

Canadian Source: National Forestry Database and U.S Source: National Interagency Fire Center

Table description

Stacked bar chart showing the estimated area burned (in hectares) over time from 1990 to 2021 for provinces and 2002 to 2021 for U.S. states near (and including) Alberta. The year with the highest total area burned was 2015 with a total of 5,439,049 hectares burned. The highest burned area in Canada was in 1995 with a total of 5,144,117 hectares burned. For the United States, the highest average burned area was in 2020 with a total of 2,735,734 hectares burned.

Wildfire smoke impacts

  • The number of wildfire smoke impacted days (daily average PM2.5 > 15 µg/m3) is similar across Alberta’s large urban centres between 2015 to 2021 (Figure 3). The notable exception is the Fort McMurray air quality monitoring station in 2016 which was significantly impacted by the Horse River Wildfire (see focused study).
  • The amount of time that wildfire smoke affects a monitoring station each year is highly variable and depends on several factors, including fire location, meteorology, among others.

Figure 3. Number of days that select large urban centre monitoring stations across Alberta were affected by wildfire smoke from 2015 to 2021.

Chart data table
Year Calgary Southeast Edmonton South Fort McMurray Athabasca Valley Grande Prairie Lethbridge Medicine Hat Red Deer Lancaster
2015 12 14 21 10 11 16 17
2016 1 4 28 2 1 1 1
2017 21 16 8 14 23 20 19
2018 21 19 15 24 23 19 18
2019 3 7 11 8 4 3 4
2020 6 2 2 2 8 4 4
2021 27 17 18 17 32 29 24

Source: Government of Alberta

Table description

Line chart showing the change over time in the total number of days in a year that Alberta’s large urban centers are impacted by wildfire smoke from 2015 to 2021. The highest number of days at a station in a given year was 32 days at the Lethbridge station in 2021. In 2016, the Horse River wildfire significantly contributed to the total number of days (28) that Fort McMurray was impacted, while other urban centres had fewer (less than 5) days impacted by wildfire smoke this year.

Seasonal variation

Wildfire prevalence

  • The timeline for wildfire activity varies across different regions (Figure 4), but wildfires generally begin in late spring and taper off in early fall. For Alberta, wildfire activity peaks in May and tends to decline in area burned through June, which is typically the province’s wettest month. Whereas, in B.C., wildfire activity peaks in July and August when conditions are hottest and driest.
  • In the most recent decade, Alberta fires have burned more hectares in May and June than in earlier decades. British Columbia fires have remained most prevalent in July, albeit, with area burned increasing over the past 3 decades, possibly due to climate change and increased human activity.

Figure 4a. Seasonal variation in monthly area burned (in hectares) for Alberta by decade from 1990 to 2019.

Chart data table
Decade 1990-1999 2000-2009 2010-2019
Jan 0.015057778 0.166651 0.00177601
Feb 0.021584 0.009009 0.01484142857
Mar 0.130096 0.675862 0.133419
Apr 0.704422 2.304288 2.33043401
May 73.413222 65.4130846 265.8514752
Jun 21.813966 63.6921721 108.5908371
Jul 14.102304 61.70057 63.33392749
Aug 38.012262 1.9959093 12.86569847
Sep 0.676535 1.308869 3.845029011
Oct 0.134773 0.221545 0.2556981
Nov 0.058721 0.130131 0.009893
Dec 0.4606033333 0.057203 0.04691888889

Source: National Forestry Database

Table description

Line chart showing the monthly average area burned (in 1000s of hectares) in Alberta over three decades (1990-1999, 2000-2009, 2010-2019). For all three decades, the average area burned peaks in May and decreases over the summer. In the 1990-1999 decade, a second, smaller peak occurs in July and August.

Figure 4b. Seasonal variation in monthly area burned (in hectares) for British Columbia by decade from 1990 to 2019.

Chart data table
Decade 1990-1999 2000-2009 2010-2019
Jan 0.005985714 0.0595115 0.003586125
Feb 0.13336 0.0084709 0.07632425
Mar 0.127481 0.0915137 0.1647318
Apr 0.8370551 0.9167308 9.8304617
May 3.5229502 7.8325976 20.5050385
Jun 5.5100462 24.975055 19.4812869
Jul 11.0371702 44.3899343 242.2245871
Aug 6.5911148 21.1649962 89.9882105
Sep 4.410957 1.4636941 0.98807701
Oct 0.4447169 0.1959242 0.235527
Nov 0.00354 0.0435375 0.026042444
Dec 0.0423275 0.012646167 0.001416

Source: National Forestry Database

Table description

Line chart showing the monthly average area burned (in 1000s of hectares) in British Columbia over three decades (1990-1999, 2000-2009, 2010-2019). For all three decades, the average area burned peaks in July. More recent decades have higher average area burned than older decades.

Figure 4c. Seasonal variation in monthly area burned (in hectares) for Saskatchewan by decade from 1990 to 2019.

Chart data table
Decade 1990-1999 2000-2009 2010-2019
Jan 0.0000625 2.001911667 0.04885
Feb 0.00001 14.4856275
Mar 0.168998333 54.736446 0.0173
Apr 1.808746 11.808775 1.393785245
May 172.1488896 21.524539 58.05930271
Jun 154.3031789 231.578279 336.3334112
Jul 69.92485255 98.474884 111.1929763
Aug 85.37531771 42.206809 57.59405315
Sep 1.988732 1.512562 3.407692222
Oct 0.08293 0.33362 1.364023062
Nov 0.010872 0.013603333 0.000125
Dec 0.00021 0.00557 0.0001

Source: National Forestry Database

Table description

Line chart showing the monthly average area burned (in 1000s of hectares) in Saskatchewan over three decades (1990-1999, 2000-2009, 2010-2019). The average area burned peaks in June with the exception of 1990-1999 which peaked in May. In the 2000-2009 decade, there is an additional smaller peak in March.

Figure 4d. Seasonal variation in monthly area burned (in hectares) for Northwest Territories by decade from 1990 to 2019.

Chart data table
Decade 1990-1999 2000-2009 2010-2019
Jan 0.00002 0.001
Feb 0.00001 1.5
Mar
Apr 0.8900625 0.02 0.00078
May 12.834074 10.32815889 38.901062
Jun 468.085732 44.97282 378.253089
Jul 417.106211 136.250022 260.1534814
Aug 62.09717 8.902317 32.081134
Sep 1.696816667 1.425936667 0.389001667
Oct 0.00328 0.002366667 0.0002
Nov 0.00015 0.001 1.115633333
Dec 0.00026

Source: National Forestry Database

Table description

Line chart showing the monthly average area burned (in 1000s of hectares) in Northwest Territories over three decades (1990-1999, 2000-2009, 2010-2019). The average area burned peaks in June and remains high into August. However, 2000-2009 peaks in July and is smaller in magnitude than 1990-1999 and 2010-2019.

Figure 4e. Seasonal variation in monthly area burned (in hectares) for Yukon Territory by decade from 1990 to 2019.

Chart data table
Decade 1990-1999 2000-2009 2010-2019
Jan 0 0 0.0001
Feb 0 0 0
Mar 0.00101 0 0
Apr 0.0413075 0.000404 0.383543333
May 7.503555 5.791563 30.5049
Jun 74.423617 182.696294 75.0364482
Jul 77.951615 48.80532 29.7300392
Aug 18.093923 2.160247778 1.911691
Sep 0.0171475 0.00767 0.02992625
Oct 0.000513333 0.07308 0.1234
Nov 0.00001 0.616 0
Dec 0 0.36215 0

Source: National Forestry Database

Table description

Line chart showing the monthly average area burned (in 1000s of hectares) in Yukon Territory over three decades (1990-1999, 2000-2009, 2010-2019). The average area burned peaks in June. In 1990-1999, the average area burned remained high into July.

Wildfire smoke impacts

  • Figure 5 shows the total number of days that Alberta’s large urban centres were affected by wildfire smoke (daily average PM2.5 > 15 ug/m3) by month during the 2015 to 2021 period.
    • Northern areas, like Fort McMurray and Grande Prairie, experienced the most wildfire smoke days earlier in the wildfire season (i.e., May) compared with other stations.
    • Southern areas, like Lethbridge and Medicine Hat, experienced the most wildfire smoke days later in the wildfire season (i.e., August)

Figure 5. Seasonal variation in monthly total number of days impacted by wildfire smoke at major urban monitoring stations in Alberta from 2015 to 2021.

Chart data table
Month Calgary Southeast Edmonton South Fort McMurray Athabasca Valley Grande Prairie Lethbridge Medicine Hat Red Deer Lancaster
Jan 0 0 0 0 0 0 0
Feb 0 0 0 0 0 0 0
Mar 0 0 0 0 0 0 0
Apr 0 0 0 0 0 0 0
May 4 12 36 17 4 2 3
Jun 1 3 11 1 2 3 1
Jul 25 18 30 23 18 25 26
Aug 43 34 21 31 50 48 42
Sep 17 9 4 5 22 12 9
Oct 1 3 0 0 6 2 2
Nov 0 0 1 0 0 0 0
Dec 0 0 0 0 0 0 0

Source: Government of Alberta

Table description

Line chart showing the total number of days from 2015-2021 that large urban centers are impacted by wildfire smoke by month. August has the most impacted days from wildfire smoke with a notable decrease in June and a second peak occurring in May.

Limitations of the dataset

  • Only days with daily average PM2.5 concentration greater than 15 µg/m3 were included in the identified wildfire smoke impacted days. There may be additional days with lower PM2.5 concentrations that were impacted by wildfire smoke but not included in the results. For data showing total number of impacted days, only urban stations were included due to limited data in rural regions.
  • Long-term air quality monitoring stations do not cover all regions of Alberta, therefore monitoring gaps may incorrectly suggest that wildfire smoke impacts do not occur in those areas.
  • Different jurisdictions might vary in their reporting of area burned due to differences in land use, among others.
    • For example, Alberta reports area burned within the province’s Forest Protection Area, while Saskatchewan reports area burned data under the Intensive Protection Zone.
  • Additionally, U.S. data from the National Interagency Fire Center is only available from 2002 onward. U.S. data beyond 2018 does not include prescribed burns (which are not expected to be significant in size).
  • Wildfire burn data from the National Forestry Database (used in this indicator) are available up until 2021 as of the posting of this indicator.

Focused study

The Alberta government deploys air quality monitoring to support emergency response during wildfires. During the 2016 Horse River wildfire in Fort McMurray, air monitoring was deployed to support decisions to protect the health of emergency response personnel and the public. The report,Characterization of air quality during the 2016 Horse River wildfire, summarizes air quality data collected during the fire.

The extent of the wildfire is shown in Figure 6. Very high concentrations of PM2.5 that exceeded health-based objectives were observed from both permanent and portable air quality monitoring equipment due to wildfire smoke. In addition to PM2.5, concentrations of NO2, ammonia (NH3), SO2, and carbon monoxide (CO) were also monitored. Median hourly NH3 concentrations were 3 times and 22 times larger during the wildfire than during the non-wildfire impacted period at the Fort McKay-Bertha Ganter monitoring station and Fort McMurray-Patricia McInnes monitoring station, respectively. Furthermore, 13 episodes of hourly CO concentrations exceeding the health-based Alberta Ambient Air Quality Objective (AAAQO) of 13 ppm were recorded at the Fort McMurray-Athabasca Valley station, and the median hourly concentrations were 2 times higher than the non-wildfire impacted period.

This demonstrates that measurements of additional parameters provide valuable information about the composition of the smoke plume and risk to human health.

Figure 6. Fort McMurray and surrounding area with air quality monitoring stations and Horse River Wildfire boundary indicated. Portable Environmental Beta Attenuation Monitors (EBAMs) and the Government of Alberta’s Mobile Air Monitoring Laboratory (MAML) were deployed to the area to track pollutant concentrations.

Fort McMurray wildfire smoke map
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