Basic Calculations for Occupational Safety and Environmental Health Professionals - Mathematics and Statistics for the Environment - page 395

equipment today are accomplished with some degree of success, air pollution problems still exist.
The environmental engineer of today and tomorrow must develop proficiency and improved under-
standing of the design and selection of air pollution control equipment in order to cope with these
problems and challenges—“to get it clear.”
It is in this spirit that this section is presented. In short, we simply feel that the present situation
is not that grim. It is not time to start shedding tears. Why do we feel this way? Simply, we know we
can do something to control environmental air pollution. Environmental professionals who are well
trained and well equipped with the proper mathematical tools can make a difference when it comes
time to clear the air we breathe.
The USEPA devotes (as it should) enormous amounts of time to research topics related to air pol-
lution control. In this section, we heavily excerpt from USEPA publications on the topic. Moreover,
much of the general information provided is excerpted from Spellman (2008). The excerpted mate-
rials have been rearranged and edited to make the materials more concise for environmental pro-
fessionals in training and general readers to understand the basic concepts of air pollution control
mathematics and processes.
Controlling environmental air pollution begins with understanding what environmental pollu-
tion is. We define environmental air pollution as the contamination of atmospheric air in such a
manner as to cause real or potential harm to human health or well being or to damage or harm the
natural surroundings without justification. Contaminants may include almost any natural or artifi-
cial composition of matter capable of being airborne (e.g., friable asbestos). Contaminants may be in
the form of solids particles, liquid droplets, gases, or in combinations of these forms. Contaminants
fall into two main groups: (1) those emitted directly from identifiable sources, and (2) those pro-
duced in the air by interaction between two or more primary contaminants, or by reaction with
normal atmospheric constituents, with or without photoactivation.
The Clean Air Act (CAA) established two types of National Ambient Air Quality Standards
(NAAQS):
• Primary standards are designed to establish limits to protect public health, including the
health of “sensitive” populations such as asthmatics, children, and the elderly.
• Secondary standards set limits to protect public welfare, including protection against
decreased visibility and damage to animals, crops, vegetation, and buildings.
15.5.1 s ix C ommon a ir p ollutants
National air quality standards have been set for six common pollutants (also referred to as “criteria”
pollutants). These common air pollutants are discharged from various sources and include
• Ground-level ozone
• Nitrogen dioxide
• Particulate matter
• Sulfur dioxide
• Carbon monoxide
• Lead
15.5.1.1 Ground-Level Ozone
Ozone (O 3 ) is a highly reactive photochemically produced gas composed of three oxygen atoms. It
is not usually emitted directly into the air (i.e., it is a secondary air pollutant) but at ground level is
created by a chemical reaction between oxides of nitrogen (NO x ) and volatile organic compounds
(VOCs) in the presence of heat and sunlight. We can characterize ozone as the Dr. Jeckel and
Mr. Hyde of air pollutants. Why? Ozone has the same chemical structure whether it occurs miles
above the Earth or at ground level and can be either “good” or “bad,” depending on its location