All about Particulate Matter

Introduction

Humans living in cities are subjected to air pollutants emitted by both outdoor and indoor sources. The outdoor sources of these pollutants, as well as the types of pollutants produced, vary depending on geographic location, weather, and local urbanisation. The majority of air pollution is caused by aerosols, which are a mixture of particles and gases. Particulate matter (PM) suspended in air has received the most attention of these because it is easily measured and easily related to the negative health effects of polluted air. 

When analysed for mass, the distribution of urban air particles reveals two peaks corresponding to coarse particles, ranging from 10 to 20 m, and fine particles, ranging from 0.1 to 2.5 m.

Although some coarse acid droplets are present in fog, the fine fraction contains the majority of the acidity (hydrogen ion) and mutagenic activity of particulate matter.

Minute solid particles or liquid droplets

The particle sizes of ambient aerosols can be measured using the NASN cascade impactor by fractionating the particles based on their aerodynamic dimensions, and the fractions can be quantified gravimetrically. 

The high proportion of particles larger than 1 m in diameter in Ankara, Turkey, is associated with incomplete lignite combustion; however, particulate concentrations in Ankara are significantly higher than those measured elsewhere.

In Cincinnati, particle growth occurs during temperature inversions; the higher proportion of large particles found during inversion periods can account for the reduction in visibility. Because of the reentrainment of debris by traffic-induced turbulence, aerosols near highways contain larger particles than those found further away.

Types of particulates

Particulate matter is one of the most difficult types of air pollution to control. Particulate matter, unlike its air pollutant counterparts, does not come from a single source, nor is it a single chemical or gas.

Particulate matter, on the other hand, is an amalgamation of different particles, both solid and liquid, that behave similarly and are of similar size. Particulate matter is further classified based on particle size into several categories.

1. Particles of Fineness (PM2.5)

The next category we’ll look at is fine particles, which are arguably the most well-known type of particulate matter. PM2. 5 is a class of particles with an aerodynamic diameter of 2.5 m or less that can penetrate deep into our lungs and even enter our bloodstream.

Fine particles can come from both natural and man-made sources, such as:

• Exhaust from motor vehicles

• Wildfires

• Emissions from power plants

• Other types of combustion activities

2. Particles of Fineness (PM2.5):

The next category we’ll look at is fine particles, which are arguably the most well-known type of particulate matter. PM2.5 is a class of particles with an aerodynamic diameter of 2.5 m or less that can penetrate deep into our lungs and even enter our bloodstream.

Fine particles can come from both natural and man-made sources, such as:

• Exhaust from motor vehicles
• Wildfires
• Emissions from power plants
• Other types of combustion activities

What is particle pollution, and what types of particles are hazardous to one’s health?

Particle pollution, also known as particulate matter or PM, is a broad term for a suspension of solid and liquid droplets in the air. Acids (such as sulfuric acid), inorganic compounds (such as ammonium sulphate, ammonium nitrate, and sodium chloride), organic chemicals, soot, metals, soil or dust particles, and biological materials are all examples of particle pollution (such as pollen and mould spores).

Particle pollution is always present in the air we breathe, both indoors and outdoors. 

Particles with a diameter of 10 micrometres (m) or less cause the most problems. These smaller particles typically enter the lungs after passing through the nose and throat. When inhaled, these particles can affect the lungs and heart, causing serious health effects in people who are most vulnerable, such as those with heart or lung disease, diabetes, older adults, and children (up to 18 years of age). 

Larger particles (> 10 m) are less dangerous because they do not enter the lungs, but they can still irritate the eyes, nose, and throat.

Conclusion

The majority of air pollution is caused by aerosols, which are a mixture of particles and gases. Particulate matter suspended in air has received the most attention of these because it is easily measured and easily related to the negative health effects of polluted air. Although some coarse acid droplets are present in fog, the fine fraction contains the majority of the acidity and mutagenic activity of particulate matter. The particle sizes of ambient aerosols can be measured using the NASN cascade impactor by fractionating the particles based on their aerodynamic dimensions, and the fractions can be quantified gravimetrically. Particulate matter, on the other hand, is an amalgamation of different particles, both solid and liquid, that behave similarly and are of similar size.