Environmental Engineering Reference
In-Depth Information
such as cardiovascular and central nervous system illnesses. Carbon monoxide is also a
contributing factor to the formation of ground-level ozone (“What are the six common air
pollutants,” n.d.).
Particle matter
Particle matter pollution refers to small solid particles (e.g., dust, dirt, soot, and smoke) and
fine liquid droplets in the form of aerosols that are suspended in the air. Particle matter can
be a primary or a secondary source of pollution. Primary particles come from trucks, buses,
factories, construction sites, tilled fields, unpaved roads, stone crushing, and wood burning
(“Particle matter,” n.d.). Secondary particles, on the other hand, are the result of chemical
reactions of primary gaseous emissions. An example is sulfuric acid and nitric acid that
combine in the atmosphere with ammonia to form ammonium sulfate and nitrate,
respectively.
Based on their aerodynamic diameter, particular matter is classified in three groups:
1. PM
10
are “inhalable coarse particles” with diameters larger than 2.5 micrometers and
smaller than 10 micrometers (Environmental Protection Agency [EPA], 2004).
2. PM
2.5
are “fine particles,” with diameters that are 2.5 micrometers and smaller (EPA,
2004).
3. PM
0.1
are “ultrafine particles with diameters less than 0.1 micrometers” (World Health
Organization [WHO], 2003).
Inhalable coarse particles come from the direct release of particles from mechanical break-
up or from larger solid particles of noncombustible material released during burning. Fine and
ultrafine particles are usually the result of chemical reactions of primary pollutants in the
atmosphere (WHO, 2003). In many countries, particles with diameters up to 10 micrometers
are regulated, whereas particles larger than 10 micrometers are not considered a danger that
needs to be regulated.
In the food industry, operations that handle grains (e.g., production of flour, rice, cornstarch,
and cereal), spices, and dry ingredients produce particle matter, especially inhalable coarse
particles. In these types of industries, dust is suspended in the air during loading and unloading,
transfer, sifting, mixing, and milling. In food plants, dust control is not only important from
the environmental pollution point of view but also to protect operators, avoid cross-
contamination, prevent accumulation of dust, which provide a source of food for rodents and
bacteria, and to avoid explosions. Fine particles of materials with high carbon content such as
starches, flours, and fine sugars can explode when suspended into the air.
When inhaled, PM
10
reaches the upper part of the airways and lungs resulting in respiratory
illnesses. Furthermore, the exposure of infants under 1 year of age to these pollutants may
result in impairment in lung function and development, asthma, and other ailments such as
cough and bronchitis. PM
2.5
have the ability to penetrate into the lung and reach the alveolar
region, and the exposure to these particles increases the chances of death from cardiovascular
diseases, respiratory diseases, and lung cancer (WHO, 2005).
Besides the effects on human health, the emission of particle matter produces also environ-
mental damage including:
Reduction in visibility caused by haze.
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Acidification of lakes and streams that affects aquatic life, kill fish and alter biodiversity.
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Changes of the nutrient balance of soils.
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Changes in the natural balance and diversity of ecosystems (EPA, 2004).
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