Particulate matter (PM) or aerosols, most ranging from between 2.5 and 10 micrometers in diameter, have many sources and can be anthropogenic or naturally occurring. Some examples include marine aerosols like salt, mineral dust from agricultural practices, biological particles such as microorganisms and their spores and pollen, wood combustion for residential heating, and transport-related aerosols (Fuzzi et al., 2015). The latter will be the focus of this section.
According to the Environmental Protection Agency (EPA) website, www.airnow.gov, anthropogenic sources of PM2.5 (considered fine particles) are generally produced from all types of combustion including motor vehicles, power plants, and residential heating. Human-produced PM10 (considered coarse dust particles) are associated with airborne residue from rock and mineral processing operations like the mining and transport of coal.
In the urban setting, concentrations of PM emissions tend to spike during the morning and evening rush hours when modes of transportation reach their zenith (Fuzzi et al., 2016). The combustion of diesel fuel and its byproducts mixing with exhaust gas is a major contributor of sulfur (SO2 & SO3) emissions into the atmosphere (Merkisz et al., 2002). sulfuric oxides and heavy metals such as Pb, Ni, Zn, and Cu are known to be primary sources of PM2.5 in a region of Finland where copper, nickel, and industrial fertilizers are produced (Eeva et al., 1998). In their 2005 global update, the World Health Organization published a PM2.5 exposure guideline of 25 ?g/m3/d and a guideline of 50 ?g/m3/d of PM10.
Airborne heavy metal pollution from an industrial copper and nickel smelter affected populations of lichens, mosses, pine trees, and the bird species Parus major L. (P. major) in the coniferous forests of southwest Finland. The study found a significant reduction in the density of green caterpillars and sawfly larvae, the birds’ primary food source, nearest the smelter. This set off a chain reaction within the P. major population as their characteristic bright yellow plumage began to fade. Dulling of plumage led to increased competition for brightly colored mates and consequently produced faded coloring in the nestlings. In addition to disruptions to the mating/offspring cycles, male-male competition, battles for social dominance, and the decreased ability to use crypticism in avoiding predators may be attributed to PM pollution. Conditions slowly improved as radial distance from the smelter increased (Eeva et al., 1998).
PM pollution studies carried out on mice and metropolitan transportation emissions have produced startling results in the area of reproductive cycles. As Carre et al. writes, Two studies were carried out on mice in the city of Sao Paulo, Brazil, which has a high level of air pollution. Mohallem et al. found a significant reduction in the number of newborns per mouse and a significant increase in the embryo implantation failure rate in female mice exposed as newborns for 3 months to the city polluted air and then mated with non-exposed males as adults (Carr?© et al.,
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