Suspended Particulate Matter in Air Pollution

Atmospheric particulate matter, also known as PM (fine dust) or particles, are fine solid or liquid substances suspended in the Earth's atmosphere. Particulate matter is the sum of all solid and liquid particles in the air, many of which are harmful. This complex mixture contains organic and inorganic particles such as dust, pollen, soot, smoke and liquid droplets. These particles vary greatly in size, composition and origin. It consists of small solid particles or liquid droplets suspended in the air. Smaller particles can penetrate deeper into the respiratory tract and are more dangerous if inhaled. Particulate matter is a problem, especially in winter in the Bay Area, where seasonal wood burning is the main cause.

Types

Particulate Matter is often divided into two main groups based on their size. Large particles for inhalation: These particles have a diametre of 2.5 microns to 10 microns (PM10 - PM2.5). Particulate matter: These particles are found in smoke and fog up to 2.5m (PM2.5). Inhalable large particles can be found near dusty roads and industrial plants, but small particles can be emitted directly from sources such as forest fires or formed when gasses emitted by power plants, industries and automobiles react in the air.

Example of Suspended Particulate Matter

Sources of Particulate Matter

Particulate matter comes from a variety of stationary and mobile sources and can be emitted to the atmosphere directly (primary emissions) or deflected gaseous emissions to the atmosphere (secondary emissions). The main sources of particulate matter are human activities and nature. Most sources of PM are generated by various human activities (anthropogenic). These activities include agricultural work, industrial processes, burning wood and fossil fuels, construction and demolition work, and airborne road dust. Natural resources (whether anthropogenic or biological) also contribute to the overall problem of PML. This includes windblown dust and forest fires. Secondary sources of greenhouse gas emissions directly release pollutants into the atmosphere. Therefore, these contaminants are considered precursors to the formation of dust particles. These secondary pollutants include SOx, NOx, VOCs and ammonia. Control measures to reduce emissions of particulate precursors.

How Is Suspended Particulate Matter Harmful?

• Asthma - Rising number of diagnoses linked to rising micro-pollution in countries around the world, especially levels of pollution in this high area.

• Lung Cancer - Fine particles penetrate deep into the human respiratory tract and enter the bronchi, impairing lung health and causing cancer.

• Cardiovascular Diseases - Many different particles have a serious effect on the heart and its functioning, which in turn is caused by the fact that microscopic particles easily enter the body unfiltered.

• Premature Birth - Exposure to high levels of air pollution increases the number of failed pregnancies, especially in cities with high rates of birth defects due to high levels of pollution.

Causes of Formation of Suspended Particulate Matter

• Volcanic - Eruptions release large amounts of particulate matter, including ash and gases, into the atmosphere.

• Dust Storms - Strong winds can throw very large clouds of dust, which in turn disperse into the atmosphere and take years to reappear. 

• Forest and Grass Fires -  Smoke from trees and grass contains a complex mixture of particles, such as carbon monoxide and hydrocyanic acid, which rise into the air and remain in the atmosphere.

• Living Vegetation - Plants that release particles such as isoprene, methanol and spores into the air. These particles can be blown away by the wind and can increase particle levels in the atmosphere.

• Ocean Spray - Due to the large amount of plastic that breaks down into nano-sized particles found in seawater around the world. These harmful particles can be released into the air with a strong spray. 

• Tornadoes and Hurricanes - These powerful weather systems can only absorb a large amount of residual dust and pollutants in rural areas. Especially when driving through cities and working with cement dust and high concentrations of common pollutants.

Artificial causes of Formation of Suspended Particulate Matter

• Coal Combustion - Coal combustion is still used for heat generation and power supply in most countries, and coal combustion directly increases the amount of carbon monoxide and other harmful particles in the atmosphere.

• Oil Burning - is used to refuel vehicles that emit a large aluminium of exhaust gases containing a large number of harmful particles throughout the world. Since cities contain large amounts of these pollutants, particles are the cause of many deaths.

• Firewood Burning - Wood combustion is the main source of particulate matter used for various purposes such as heating and power generation. The combustion process releases many cocktails of toxic pollutants into the atmosphere, such as soot. 

• Construction - Cement dust makes up a significant proportion of the total amount of pollutants in the world. Due to the small size of dust particles, they can hang in the air for quite a long time. Vehicle use in the construction industry and other known pollutants.

What Does Suspended Particulate Matter Includes?

Suspended particulate matter contains lithogenic material, including quartz, feldspars, and hydrous aluminium silicate muds (like Kaolinite, illite, chlorite, and montmorillonite), and iron and manganese oxides. Colloidal materials are made out of inorganic oxides aluminium, iron, manganese, and silicon; humic substances; and polysaccharides, along with carbonates, muds, and organisms. The centralization of complete Fe in estuarine SPM goes from 10 to 50 mg g−1, 95% of which is grid bound and, thusly, lifeless. The leftover Fe is a surface film of inadequately solidified FeOOH, for example, ferrihydrite.

Convergences of complete Mn are lower than Fe and reach 1.1-13 mg g−1; as opposed to Fe, a large portion of the manganese oxide (as MnOOH) is situated on the outer layer of the SPM (Turner and Millward, 2002). Formless hastens of iron and manganese oxyhydroxides have SSAn that reaches 200 to 400 m2 g−1, which presents upgraded reactivity to the particulate stage (Millward et al., 1990; Turner et al., 1991). The outer layer of SPM is likewise covered with a biofilm of living and dead parts which, along with other biogenic matter, is characterised as particulate natural matter (POM). Synthetically, POM is overwhelmed by POC and natural nitrogen.

How Suspended Particulate matter Causes Global Warming?

Aerosols can be either solid or liquid. Most of them are formed as a result of natural processes, such as volcanic eruptions, and some are formed as a result of human industrial and agricultural activities. Aerosols have a significant impact on climate change. Bright aerosol particles can reflect energy from the sun into cloudless air, while dark particles can absorb it. The net global effect over the historical period is that aerosols have partially offset increases in global mean surface temperature. Aerosols can change the amount of energy reflected by clouds and can change atmospheric circulation patterns.

Interesting Facts

Particulate matter small enough to be inhaled has the greatest potential to affect human health. This includes particles that have aerodynamic diameters that are 10 µm or less (PM10). The smaller the particle, the better able they are to evade the body's defenses and penetrate deep into the lungs.

Important Questions

1. What are the types of Suspended Particulate matter?

Ans: Particulate Matter is often divided into two main groups based on their size. Large particles for inhalation: These particles have a diameter of 2.5 microns to 10 microns (PM10 - PM2.5). Particulate matter: These particles are found in smoke and fog up to 2.5m (PM2.5). Inhalable large particles can be found near dusty roads and industrial plants, but small particles can be emitted directly from sources such as forest fires or formed when gasses emitted by power plants, industries and automobiles react in the air.

2. What are the diseases caused by Suspended particulate matter?

Ans: Air pollution is a world public health problem. Particulate matter , a mix of solid and liquid particles in the air, becomes an increasing concern in the social and economic development of China. For decades, epidemiological studies have confirmed the association between fine particle pollutants and respiratory diseases. It has been reported in different populations that increased Fine particulate matter  concentrations cause elevated susceptibility to respiratory diseases, including acute respiratory distress, asthma, chronic obstructive pulmonary disease, and lung cancer. This review will discuss the pathophysiology of PM2.5 in respiratory diseases, which are helpful for the prevention of air pollution and treatment of respiratory tract inflammatory diseases.

Key Features

• Particulate matter (PM) is a fine solid or liquid substance that can be released into the atmosphere from combustion processes, industrial activities or natural sources. 

• Particulate matter comes from a variety of stationary and mobile sources and can be emitted to the atmosphere directly (primary emissions) or deflected gaseous emissions to the atmosphere (secondary emissions).