Everything to know about Particulate Matter (PM)
Particulate matter (PM) is a common air pollutant harmful to human health that is recognized for monitoring and mitigating by the World Health Organization and Breeze Technologies. Read on to find out more.
What is particulate matter?
Particulate matter consists of solid and liquid airborne particles and is classified by the size of its particles. PM10 are coarse particles that have diameters that are less than or equal to 10 micrometres, while PM2.5 are fine particles with diameters less than or equal to 2.5 micrometres. For scale, the human hair has a diameter of roughly 70 micrometres. There are also newer classifications such as PM0.1, PM0.3, PM0.5, PM4, and PM5, but the aforementioned PM2.5 and PM10 are the main ones, as they are regulated.
What are sources of particulate matter?
Primary particulate matter is emitted from a direct source, such as power plants, factories, diesel and petrol engines, vehicle braking, tire-wear, construction sites, forest fires, volcanos, dust storms, stoves, heaters.
Below is a table with more information on typical sources based on the specific size categories of PM:
|PM0.1, PM2.5, PM10||Transport vehicles, industrial emissions, construction work, biomass burning, agricultural processes, cooking, cigarette smoke, volcanic particles, marine aerosols, forest fires|
|PM4||Crystalline silica emissions|
Primary particulate matter can consist of:
- Sodium chloride (sea salt)
- Black carbon from fossil and biomass fuel combustion
- Trace metals (lead, cadmium, copper, nickel, chromium, zinc, manganese, vanadium) from metallurgical processes, industry fuels, and mechanical abrasion processes
- Mineral components (aluminum, silicon, iron, calcium) from construction, demolition work, and quarrying
On the other hand, secondary particulate matter is formed as a result of chemical and physical reactions with compounds such as sulfur dioxide (SO2), nitrogen oxides (NOx), ammonia (NH3), and volatile organic compounds (VOCs). This occurs through a process called nucleation, where the gaseous molecules of ammonia condense to form either liquid or solid particles suspended in the atmosphere.
Secondary particulate matter can consist of:
- Sulfate, which is formed by the oxidation of SO2 to sulfuric acid (H2SO4) reacting with NH3 to form ammonium sulfate ((NH4)2SO4)
- Nitrate, which is formed by the oxidation of NOx to form nitric acid (HNO3) reacting with NH3 to form ammonium nitrate (NH4NO3). It can also react with sodium to form sodium nitrate (NaNO3)
- Water, from the atmospheric water taken by (NH4)2SO4 and NH4NO3 during the chemical reaction
Both primary and secondary PM can also contain organic carbon compounds, of which there are two types: primary organic carbon comes from traffic or industrial combustion processes, while secondary organic carbon is from the oxidation of volatile organic compounds (VOCs). Examples include aliphatic and aromatic hydrocarbons, heterocyclics and oxygenates (aldehydes, ketones, and carboxylic acids).
What is the health impact of particulate matter?
Particulate matter is linked to reduced lung function, pneumonia, irregular heartbeats, heart attacks, strokes, and cardiovascular and respiratory diseases such as asthma, bronchitis, emphysema, chronic obstructive pulmonary disease (COPD), and lung cancer.
It has been found that the smaller the particle, the higher the health risk because of its ability to penetrate deeper into the body. Generally, PM10 irritates the eyes, nose, and throat, while PM2.5 is able to penetrate deep into the respiratory and circulatory systems, thus causing damage to the lungs, heart, and brain.
Particulate matter pollution costs individuals anywhere from 2-5 years from their lives. Specifically, long-term exposure to an additional 10 μg/m3 of PM2.5 reduces life expectancy by 0.98 years. This is worse than other health risks, including smoking, alcohol and drug use, unsafe water and sanitation, tuberculosis, HIV/AIDS, and even conflict and terrorism.
What is the environmental impact of particulate matter?
Particulate matter is capable of being carried long distances by wind and then settling on land or water. Depending on its chemical composition, environmental effects may include:
- Acidifying lakes and rivers
- Changing the nutrient balance in coastal waters and river basins
- Depleting soil nutrients
- Damaging sensitive forests and farm crops
- Affecting ecosystem diversity
- Contributing to acid rain effects
- Damaging building materials
In addition, black carbon, a component of PM2.5, is a short-lived climate pollutant with a warming impact that is 460-1,500 times higher than carbon dioxide. Aside from contributing to global warming, black carbon influences cloud formation and influences rainfall patterns, which affect both ecosystems and human livelihoods.
How can particulate matter emissions be lessened?
The best way to lower particulate matter emissions is to target its sources. For primary particulate matter, this would be reducing fossil and biomass fuel usage. For secondary particulate matter, this would be limiting the production of ammonia (NH3), nitrogen oxides (NOx), sulfur dioxide (SO2), and volatile organic compounds (VOCs) in the atmosphere.
However, clean air actions are only effective with proper monitoring. Tracking PM levels will help identify the areas that need immediate attention and gauge the success of the targeted interventions. At Breeze Technologies, our compact, lower-cost sensors are easy to deploy on urban, rural, and industrial infrastructure, with the data gathered in real-time to form an effective air quality network run on our Breeze Environmental Cloud. We measure for both PM10 and PM2.5 as well as the precursor pollutants for secondary PM, including NH3, NO, NO2, SO2, and VOCs. Contact us today to make clean air a reality for all!