Particulate Matter Indicator

The Particulate Matter Indicator estimates the primary particulate matter emissions associated with Canadian agricultural activities from 1981 to 2016. Particulate matter is a mixture of solid particles and liquid droplets of varying size and chemical composition that are suspended in the air. It is classified as either primary particles emitted directly into the air or as secondary particles formed in the air by chemical or physical processes.

Overall state and trend

Particulate matter emissions have been decreasing on agricultural lands in Canada, with a decline of 70% for total suspended particulate (TSP), 68% for PM10 and 63% for PM2.5 since 1981 (refer to Figure 1 below in the text box "What do the different size classes of particulate matter represent?" for an explanation of size classes). In 2016, emissions were 1,889 kilotonnes (kt) for TSP, 605 kt for PM10 and 206 kt for PM2.5. The greatest improvements have occurred in the Prairie Provinces and can mainly be attributed to a reduction in summerfallow, along with a shift to reduced tillage and no-till practices in this region, which has reduced the quantity of particulates produced during land preparation and harvesting.

What do the different size classes of particulate matter represent?

Particulate matter is comprised of millions of different chemical compounds, dust and biological material, including feather fibres, dander and bacteria. These particles are classified according to their aerodynamic diameter (which is a means of measuring their size as they have irregular shapes). They are defined as follows:

Particles with an aerodynamic diameter of less than 2.5 micrometres. These particles are easily inhaled into the lower airways (the gas-exchange regions of the lungs) and deposited in the lungs, causing adverse health effects.
Particles with an aerodynamic diameter of less than 10 micrometres, including PM2.5. These particles can be inhaled into and settle in the bronchi and lungs, leading to health problems.
Total suspended particulates consist of all particulate matter suspended in the atmosphere with an aerodynamic diameter of less than 100 micrometres.
Figure 1: Particle matter size classes – adapted from the United States Environmental Protection Agency (2004)
Description of this image follows.
Description - Figure 1

The diagram uses a human hair, between 50 and 70 micrometres in diameter to illustrate the particulate matter size classes.

TSP corn pollen up to 120 micrometres in diameter

PM10 Dust, mould, etc. less than 10 micrometres in diameter

PM2.5 combustion particles, organic compounds, metals, etc. less than 2.5 micrometres in diameter

Use the interactive map below to zoom in and explore different regions. Note that the regions showing the highest emission levels are found within the Prairies, and both the Lake Erie Lowland region of southeast Ontario and the Saint Lawrence Lowlands region of Quebec contain some pockets of very high emissions.

Since 1981, there has been a significant decrease in emissions across Canada, particularly evident across the Prairies, as well as in parts of Ontario and Quebec. Pockets of decline can be seen in southern BC and in parts of Quebec, as well as in the Maritimes.

Generally speaking, the large improvements in the Prairies can be mainly attributed to the reduction in summerfallow – a practice of leaving fields bare – as well as an increase in reduced tillage and no-till practices, which have reduced the amount of bare soil exposed to degradation and therefore the quantity of particulates produced during land preparation and harvesting. The isolated increases in emissions elsewhere can be explained by shifts in cropping practices and crop types. The sharp decline in beef cattle production between 2006 and 2016, as well as a longer-term decline in dairy herds since 1981, has reduced the area under pasture and forage production. Much of the area previously dedicated to these land uses has been converted to annual crops, such as corn, which do not provide as much cover as perennial crops, and increase the risk of particulate matter emissions during land preparation and harvesting. In spite of this however, overall trends are improving on a national basis.

Figure 2: Total suspended particulate emissions in Canada, 2016
Very low Low Moderate High Very high

Use the map in Figure 3 to explore the change in total suspended particulate between 1981 and 2016. It is apparent that the decrease in particulate matter emissions is most significant in the Canadian Prairies.

Figure 3: Change in Total Suspended Particulate, 1981 to 2016
Large decrease Moderate decrease No change Moderate increase Large increase

Particulate Matter performance index

The state and trend of the Particulate Matter Indicator can also be seen in the performance index below.

Figure 4: Particulate Matter Index

Description of this image follows.
Description - Figure 4
Year Index Value
1981 14
1986 15
1991 17
1996 20
2001 26
2006 39
2011 47
2016 51

In 2016, the state of particulate matter emissions resulting from farming activities in Canada was "Moderate". The index illustrates an improving trend, representing a reduction in particulate matter emissions between 1981 and 2016. This reduction is primarily attributed to the widespread adoption of reduced tillage and no-till, as well as decreases in the use of summerfallow in Manitoba, Saskatchewan and Alberta.

The index tends to aggregate and generalize trends and so should be viewed as a policy tool to give a general overview of state and trend over time.

About the performance indices

Specific trends

Prairie farmland sees a significant reduction in particulate matter since 1981

The Prairie Region has seen significant reductions in particulate matter emissions over the past 30 years. While there are still pockets of high or very high emissions, much of the agricultural land within the Prairie Provinces has moved into a lower emission class category. You can explore these improvements in the maps below.

Figure 5: Change in total suspended particulate emissions (kg ha-1 yr-1) in the Prairies between 1981 and 2016
Very low Low Moderate High Very high

These reductions can also be seen in the table below, which reports in actual emissions, measured in kilotonnes per year. The most dramatic reductions in emissions have occurred in Alberta and Saskatchewan. Due to the large area of agricultural land in these two provinces, these improvements have strongly influenced the national trend of improvement, although all provinces demonstrated some improvement.

Table 1a: Total particulate matter emissions (in kilotonnes per year) from Canadian farms, 1981 to 2016

TSP Emissions (kt yr-1)
  1981 1991 2001 2006 2011 2016
British Columbia 55 47 37 28 26 22
Alberta 1,507 1,388 873 651 452 405
Saskatchewan 3,323 2,980 1,782 1,173 785 631
Manitoba 756 681 558 451 396 468
Ontario 499 416 405 181 192 215
Quebec 150 170 239 125 119 127
Atlantic Provinces* 25 21 24 20 22 21
Canada 6,315 5,704 3,918 2,629 1,992 1,889
*The Atlantic Provinces include New Brunswick, Nova Scotia, Prince Edward Island and Newfoundland and Labrador

Table 1b: PM10 emissions (in kt yr-1) from Canadian agricultural operations, 1981 to 2016

PM10 Emissions (kt yr-1)
  1981 1991 2001 2006 2011 2016
British Columbia 13 11 8 6 6 5
Alberta 453 419 260 199 143 132
Saskatchewan 1,092 986 578 381 264 229
Manitoba 250 239 193 163 142 169
Ontario 46 42 37 36 36 41
Quebec 20 19 25 24 22 24
Atlantic Provinces* 5 5 5 5 5 5
Canada 1,879 1,721 1,107 814 619 605
*The Atlantic Provinces include New Brunswick, Nova Scotia, Prince Edward Island and Newfoundland and Labrador

Table 1c: PM2.5 emissions (in kt yr-1) from Canadian agricultural operations, 1981 to 2016

PM2.5 emissions (in kt yr-1)
  1981 1991 2001 2006 2011 2016
*The Atlantic Provinces include New Brunswick, Nova Scotia, Prince Edward Island and Newfoundland and Labrador
British Columbia 5 4 3 3 2 2
Alberta 141 130 83 63 45 40
Saskatchewan 309 281 176 125 91 84
Manitoba 70 66 55 48 42 51
Ontario 19 17 15 14 14 16
Quebec 8 8 10 10 9 10
Atlantic Provinces* 2 21 2 2 2 2
Canada 555 5,704 344 264 206 206

Reason for this trend

The primary reason for the improvement in this indicator in Canada is the shift away from practices which lead to significant particulate matter, such as summerfallow and intensive tillage. Particulate matter emissions from land preparation, wind erosion, fertilizer application and harvest are reduced through fewer tillage operations, and the resultant increase in soil residue. Figure 5 shows the change in percentage of farmland between 1981 and 2016 under summerfallow, under no-till for the Prairies (Alberta, Saskatchewan and Manitoba), and for Canada as a whole. Because the Prairie Region accounts for over 85% of farmland in Canada, changes in these provinces significantly impact the national averages.

Figure 6: Trends in summerfallow and no-till in the Prairies, 1981 to 2016.
(Note that Census data for tillage practices are available from 1991 onwards only).

Description of this image follows.
Description - Figure 6
Percentage area of summerfallow
  1981 1986 1991 1996 2001 2006 2011 2016
Manitoba 12 10 6 6 5 3 2 1
Saskatchewan 36 30 30 24 17 14 9 3
Alberta 21 19 16 13 11 9 5 2
British Columbia 10 12 9 6 6 4 3 1
Canada 24 20 19 15 11 9 6 2
Percentage area of no-till
  1981 1986 1991 1996 2001 2006 2011 2016
Manitoba     5 9 13 21 24 20
Saskatchewan     8 19 35 57 68 73
Alberta     3 10 27 47 64 69
British Columbia     4 9 13 19 27 36
Eastern Canada     4 14 19 24 28 24
Canada     6 15 28 46 56 59

Why this indicator matters

Particulate matter is recognized as an air pollutant that decreases visibility; contributes to stratospheric ozone depletion, acid rain and smog; and influences climate by altering both the amount of solar energy reaching the earth's surface and the amount of energy radiating back into space.

Agriculture has long been recognized as a significant contributor of atmospheric particulate matter emissions. Primary particulate emissions (particles released intact into the air) result from processes such as wind erosion and tillage (soil dust), burning (soot), crop harvesting and grain handling (grain dust). Ammonia emissions are the main agricultural source of secondary particulate matter (that is, those particles that are formed in the air). Figure 7 shows the main sources of particulate matter.

Figure 7: Main activities and factors contributing to primary and secondary particulate matter (PM) emissions in agriculture
Description of this image follows.
Description - Figure 7

The graphic illustrates the on-farm sources of particulate matter and the size of particulate matter associated with each. The following activities and factors generate all three sizes of particulate matter (TSP, PM10 emissions and PM2.5 emissions): wind erosion; land preparation; crop harvest and grain handling, agrochemical and manure application; and animal feeding. Residue burning and animal cremation generates PM2.5 emissions. In addition, the following activities generate chemicals that are precursors to secondary particulate matter: animal feeding (which generates ammonium – NH3); some types of crop produce biological volatile organic compounds (VOCs); and soils can generate nitric oxide (NO).

Agriculture has the potential to mitigate particulate matter emissions by implementing beneficial management practices.

Beneficial management practices

In the Prairies especially, those practices recommended for the prevention of soil erosion can lower particulate matter emissions. These include reducing summerfallow and tillage intensity and by increasing soil cover on cropland. Other options include increasing the area of permanent grassland; using forages in rotations; growing winter cover crops; and using strip cropping, contour cultivation and windbreaks.

Primary particulate matter can also be emitted from animal feeding operations such as barns or on feedlots. Emissions can be reduced by decreasing animals' confinement time (or increasing the grazing period), collecting litter and manure more frequently, installing dust extraction or filtered ventilation systems, and sprinkling water mist or oil onto the floor or ground surface to reduce dust.

About the performance indices

The agri-environmental performance index shows environmental performance state and trends over time, based on weighting the percentage of agricultural land in each indicator class, such that the index ranges from 0 (all land in the most undesirable category) to 100 (all land in the most desirable category). An index value that is increasing over time suggests improving environmental performance, while a decreasing index value suggests deteriorating environmental performance over time.

Related indicators

  • The Soil Erosion Indicator tracks the health of Canadian agricultural soils as it relates to the risk of erosion from tillage, water and wind.
  • The Soil Cover Indicator summarizes the effective number of days in a year that Canadian agricultural soils are protected by vegetation, crop residue or snow.
  • The Ammonia Indicator estimates the annual emissions of ammonia to the atmosphere from livestock production and fertilizer applications on Canadian farmland.

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