Particulate Air Pollution
Full Profile
IARC Monograph Vol. 46, 1989 (Group 2A)
General Information
Particulate air pollution is formed as a by-product of fuel combustion (gasoline, diesel, wood, residential heating oil, etc.) and of industrial processes. Natural sources of particulates include windblown dust and forest fires.
Particulate air pollution consists of a complex mixture of solid particles and liquid droplets, with varying chemical and physical composition[2] and so is not defined by its chemical composition. Particulate matter may contain a ‘broad range of chemical species, including elemental and organic carbon compounds, oxides of silicon, aluminum and iron, trace metals, sulphates, nitrates and ammonia’.[3]
Particulate air pollution is instead classified according to its size. Particulates range in size from 0.005 µm to 100 µm in diameter, although most suspended particles are less than 40 µm in diameter.[3] Suspended particulates are commonly classified as follows: less than 0.1 µm in diameter (ultrafine); less than 2.5 µm in diameter (fine, or respirable fraction); between 2.5 and 10 µm in diameters (coarse, or inhalable fraction); or all particles up to about 40 µm (total suspended particulates or TSP). It may also be referred to simply as PM10 (all particles sized 10 µm or less), PM2.5 (all particles sized 2.5 µm or less), or TPM (total particulate matter).[2]
- Ultrafine particles (less than 0.1 µm in diameter) are formed directly in combustion exhaust, mainly from the condensation of hot vapours,[3] but can aggregate and coagulate over time to form fine particulates.[2] Ultrafine particles typically last only a short time in the atmosphere.[3]
- Particles in the fine fraction (2.5 µm in diameter or less) are produced mainly by combustion processes and by atmospheric reactions between precursor gases such as sulphur dioxide, nitrogen oxides, ammonia and some volatile organic compounds.[2,3] Fine particles are composed primarily of sulphate, nitrate, ammonium, inorganic and organic carbon compounds, and heavy metals.[3]
- In the coarse fraction (between 2.5 and 10 µm in diameter), particles are mainly from re-suspended road dust, windblown dust, and materials handling, grinding and crushing operations.[2] Derived mainly from the Earth’s crust, these particles may contain oxides of iron, calcium, silicon and aluminum.[3]
Chimney soot has been demonstrated to cause skin cancer, particularly of the scrotum, and has been associated with increased risk of lung cancer, oesophageal cancer, primary liver cancer and leukemia in humans.[4] Soots contain a number of known and potentially carcinogenic chemicals, including arsenic, cadmium, chromium, nickel, benz[a]anthracene, benzo[a]pyrene, debenz[a,h]anthracene, and indeno[1,2,3-cd]pyrene.[5]
Diesel engine exhaust, when inhaled, has been associated with increased risk of lung and bladder cancer in humans and with the development of malignant lung tumours in rats.[6]
Exposure to gasoline engine exhaust has been associated with a general increased risk for cancer (no particular site) in humans, although some studies show no associations.[6]
Additionally, short-term exposure to particulates has been associated with increased all-cause mortality and hospitalizations for respiratory and cardiovascular diseases, while longer-term exposure has been associated with increased mortality and respiratory disease symptoms, and decreases in lung function.[7]
Particulate air pollution has been ranked by CAREX Canada for environmental settings as Group A (immediate high priority). Prioritization was based on the carcinogenic properties of particulate matter, the prevalence of exposure in Canada, and the feasibility of assessing exposure. Occupational exposures to individual constituents of particulate pollution are discussed in specific profiles for metals, polycyclic aromatic hydrocarbons (PAHs), and diesel exhaust.
Regulations and Guidelines
Canadian Agencies/Organizations
| Agency | Designation/Position | Year |
|---|---|---|
| CEPA | PM10 and PM2.5: Schedule 1, paragraph ‘c’ |
1999[3] |
| CEPA | Emissions of particulate matter from copper and zinc smelter operations: Schedule 1, paragraphs ‘a’ and ‘c’ |
1999[8] |
Air Quality Guidelines
| Canadian Jurisdictions | Level (mg/m3) |
|---|---|
| Canadian Reference Level(a) 24 hour average PM10 |
25 |
| Canadian Reference Level 24 hour average PM2.5 |
15 |
| Canada-Wide Standard for 24 hour average PM2.5(b) | 30 |
| Other Jurisdictions | Level (mg/m3) |
| US EPA[10] 24 hour average PM10(c) |
150 |
| US EPA[10] 24 hour average PM2.5(d) |
35 |
| US EPA[10] Annual average PM2.5(e) |
15 |
| WHO[11] 24 hour average PM10 |
50 |
| WHO Annual average PM10 |
20 |
| WHO 24-hour average PM2.5 |
25 |
| WHO Annual average PM2.5 |
10 |
Environmental Exposures
Canadians are exposed to fine and ultrafine particles by breathing outdoor air containing emissions from any combustion source, including industrial processes, gasoline and diesel engine exhausts, fireplaces, furnaces, prescribed burning for forestry and agricultural purposes, and naturally-caused wildfires.
Exposure also occurs through inhalation of indoor air containing fine particles emitted by wood-burning or kerosene-fuelled appliances, burning cigarettes, candles or incense,[7] and high-temperature food cooking.
National Pollutant Release Inventory
| NPRI 2009[12] | |||
|---|---|---|---|
| All amounts released into environment (air) | |||
| PM Type | # of companies | Quantity | Industry |
| Total PM | 1,166 | 284,916 t | Resource extraction and processing, manufacturing |
| PM10 | 3,532 | 123,809 | |
| PM2.5 | 51,481 t | 62,392 | |
Sources
- Wikimedia Commons Photo, Diesel Smoke
- Brauer, M 2002. ‘Chapter 2: Sources, Emissions, Concentrations, Exposures and Doses.’ A Citizen’s Guide to Air Pollution, 2nd Edition. Eds. David V. Bates and Robert B Caton. David Suzuki Foundation, Vancouver, B.C.
- Priority Substances List assessment report (CEPA) for Respirable Particulate Matter Less than or Equal to 10 µm (PM-10) (2000)
- IARC Monograph Summary, Volume 35, 1987 (PDF)
- NTP 12th Report on Carcinogens for Soots (2011) (PDF)
- IARC Monograph Summary, Volume 46, 1989 (PDF)
- CEPA/FPAC Working Group, 1999. National Ambient Air Quality Objectives for Particulate Matter Part 1: Science Assessment Document. Health Canada and Environment Canada, Ottawa.
- Priority Substances List assessment report (CEPA) for Releases from primary and secondary copper smelters and refineries - Releases from primary and secondary zinc smelters and refineries (2001)
- Canadian Council of Ministers of the Environment, 2000. Canada-Wide Standards for Particulate Matter (PM) and Ozone. Quebec City.
- US Environmental Protection Agency National Ambient Air Quality Standards (2008)
- World Health Organization, 2006. WHO Air quality guidelines for particulate matter, ozone, nitrogen dioxide and sulfur dioxide Globa Update 2005 Summary of risk assessment. Geneva.
- The National Pollutant Release Inventory
- Environment Canada, 2007. National Air Pollution Surveillance (NAPS) Network Annual Data Summary for 2004
