Table 3.

Environmental and human health risks of PM, with the most notable effect being on the respiratory tract

PM configuration	Environmental threat	Concomitant health risks	Reference
Particles of 2.5–10 μm diameter, referred to as coarse thoracic particles (PM2.5–10)	Random coalescence with aerial pollutants impairs air quality. Little effect of gravity in native state complicates their degradation. Combined with structural toughness, accidental water solubility affects the aquatic habitat by enhanced oxidative stress.	Accumulate in the respiratory system and bloodstream, aggravate asthmatic risks, stimulate nonfatal heart attacks, impair lung function, aggravate airway irritation, coughing, or breathing difficulty	[15]
Particles <2.5 μm diameter, referred to as fine particles (PM2.5)	Makes lakes and streams acidic, alters the nutrient balance in aquatic habitats, depletes soil nutrients. Black carbon portion resulting from incomplete combustion has several detrimental effects on health and climate, comprised of carcinogens and diesel-engine exhaust.	Smaller dimensions can make them reach deep into the alveoli, aggravated lung irritation causing liquids and gases to pass through lungs, increased lung-tissue inflammation that affects heart function, clotting-mediated increased stroke risk, increased incidence of lung cancer, and breathlessness.	[23]
Ultrafine particles, <0.1 μm in size	Contribute to mounting air pollution, difficult to settle due to small dimensions, can agglomerate with smoke, fog, and dust particles (smog) to increase airborne toxicity, intensify the infection tendency of airborne pathogens and related inflammatory response.	Particles of 50–100 nm ranged particles are highly random in their interactions, interfere in biological reactions via elevating oxidative stress, penetrating deep into the respiratory tract, and even crossing biological barriers, aggravating the pathogenesis of respiratory diseases and complicating their treatment. Adverse inflammatory responses, more risk for those employed in incense-manufacturing industries.	[26]