Air Quality

Question 1

Globally, how many premature deaths can be attributed to ambient air pollution and how does air pollution rank as a risk factor?

Answer 1

Globally, 4.5 million premature deaths can be attributed to air pollution and air pollution ranks as the 5th highest risk factor for premature death.

Question 2

How does air pollution affect human health?

Answer 2

Air pollution can contribute to a premature death due to damage caused in the cardiac and respiratory system.

Question 3

What factors can influence LOCAL air quality?

Answer 3

Proximity to power plants, highways, industry, and mountains significantly influence local air quality.

Question 4

What factors influence REGIONAL air quality?

Answer 4

Global air circulation patterns, latitude, and air temperature profoundly influence regional air quality.

Question 5

What are the roles of scientists and engineers in regard to air quality?

Answer 5

Scientist and engineers calculate the amount of pollutants emitted from a point source, they analyze how those pollutants may be transported to expose a population downwind from the the source. They can also help to determine what health effects may be incurred by the exposed population and what technologies may be used to reduce emissions and exposure.

Question 6

What is the composition of clean air?

Answer 6

Clean air is made up primarily of nitrogen (78.08%), oxygen (20.95%), and argon (0.93%). The remaining components of the air that are of concern as environmental pollutants are present in quantities of less than 1% in the atmosphere.

Question 7

How is an air pollutant classified?

Answer 7

Any chemical or substance that is present in the atmosphere in quantities that negatively impact human health, the environment, and the economy, or unreasonably interfere with the enjoyment of life, property, or recreation.

Question 8

What are some sources of pollutant emissions?

Answer 8

Pollutants are emitted as a result of processes producing energy for heat, work, or electricity. As a result, growing cities, climate change, population growth, and an increase in demand for energy have resulted in poor air quality in many locations.

Question 9

What are some important aspects of the Clean Air Act of 1963 and 1970?

Answer 9

• The Clean Air Act (CAA) of 1963 was the first federal act in the United States to allow regulations for the control of air pollutants.
• The CAA of 1970 was the first comprehensive step by the federal government to limit emission of air pollutants from both stationary and mobile sources (i.e. buildings and vehicles).
• The 1970 CAA also established National Ambient Air Quality Standards (NAAQS).

Question 10

What are the National Ambient Air Quality Standards (NAAQS)?

Answer 10

The NAAQS are goals set to achieve reasonable air quality in all regions of the United States. The 1977 CAA Amendments focused on improving air quality in regions where the concentrations of pollutants in the air were found to be higher than the target goals of the NAAQS. In 1990, the program was expanded to bring regions into compliance with the NAAQS, set more stringent standards for new sources, and included provision for stratospheric ozone protection.

Question 11

What does the CAA (Clean Air Act) require of regions that are either above or below the NAAQS?

Answer 11

The CAA requires all regions in the Unites States to develop Prevention of Significant Deterioration (PSD) standards to maintain air quality in regions that are in compliance with the NAAQS. However, if a region is not in compliance, the CAA requires that it develop a State Implementation Plan (SIP) to improve air quality.

Question 12

What are ‘primary pollutants’?

Answer 12

These pollutants have demonstrable negative effects on human health.
NAAQS are defined for (6) Carbon monoxide, Lead, Nitrogen dioxide, Ozone, Particulate Matter (PM2.5 & PM10), and Sulfur Dioxide.

Question 13

What are ‘secondary standards’?

Answer 13

Secondary standards are required for air pollutants that may have potentially negative environmental effects, including plant damage, decreased visibility, and architectural damage.

Question 14

What is the Air Quality Index?

Answer 14

Developed by the Environmental Protection Agency, the air quality index (AQI) was developed to help communicate air quality trends to the public and to provide warnings to the public on days that a region is not in compliance with the NAAQS. The AQI relates daily air pollution concentrion for ozone, particulate pollution, NO2, CO, and SO2 to health concerns for the general public. AQI below or at 100 is fine, above is unhealthy, especially for sensitive populations.

Question 15

Who cares about air pollution?

Answer 15

Cleaner air leads to better health and higher productivity for workers; AND better health saves money on medical expenses.

Question 16

How exactly does air pollution affect human health?

Answer 16

Pollutants enter the body through the respiratory system. Acute (short-term) systems can affect those predisposed to adverse respiratory conditions. Chronic or long-term effects of exposure to air pollution can include chronic inflammation of the bronchial tubes, sustained airway constriction, or pulmonary emphysema (the condition resulting in shortness of breath due to the destruction of the alveoli membranes in the lungs).

Question 17

What are some respiratory distress symptoms?

Answer 17

Hypoxia: caused by an inadequate supply of oxygen to the body
Hypercapnia: a condition that occurs when too much carbon dioxide builds up in the bloodstream causing distress
Constricted Airways: may lead to edema and secondary infections in the lungs
Damage Cell Tissue: prevents airways from transferring oxygen and CO2 from the blood stream, leading to necrosis and edema

Question 18

Effects and explanation of carbon monoxide pollution

Answer 18

CO is similar in size and molecular mass to O2 and will replace oxygen in the bloodstream if present in the air at high concentrations. This reduces oxygen transport to the brain, organs, and muscles. As CO levels increase in the blood stream individuals experience headaches, reduced hand-eye coordination and can result in fainting, coma, and death.
A majority of carbon monoxide emissions are from mobile sources.

Question 19

Effects and explanation of Lead pollution

Answer 19

Major emission sources of lead in the United States include lead smelters, ore and metal processing facilities, and aviation fuel.
Ingested dust form lead-based pain in older homes is one of the primary routes of lead exposure. Lead negatively affects the nervous system, kidney function, immune systems, and the oxygen-carrying capacity of the blood. Infants and children under the age of 5 are especially vulnerable to the neurological effects of lead exposure.

Question 20

Effects and explanation of Nitrous Oxides (NOx)

Answer 20

NOx is formed from the emission of combustion processes from both mobile and stationary sources.
NOx contributes to the levels of ground level ozone and are linked to adverse human health effects.
NO2 is a known irritant to the alveoli after exposures of 30 min to 24hrs.
NOx in the air increases an individuals susceptibility to pulmonary infections.
NOx reacts with volatile organic compounds (VOCs) to form ozone in the presence of heat and sunlight.

Question 21

What are primary and secondary pollutants?

Answer 21

A primary pollutant is emitted directly to the atmosphere and the original chemical form has negative impacts on people or the environment.
Secondary Pollutants (such as tropospheric ozone) are produced in the atmosphere via chemical reactions.

Question 22

Describe the process of how tropospheric ozone forms.

Answer 22

Ozone in the troposphere forms on warmer days when the chemical precursors to ozone are prevalent. Gasoline and diesel engines emit VOC’s and NOx from automobiles. So, ozone concentrations are highest during the day and decreased in intensity in the evening ultimately stopping. However, NO2 concentrations increase and build back up in the evening when ozone formation ceases.
Ozone can also be transported long distances by wind which worsens air quality in rural areas.
Ozone in concentrations as low as 1ppm(v) constrict and irritate the airways in the lungs.

Question 23

Effects and explanation of Particulate Matter

Answer 23

Particulate matter are very small airborne solid or liquid mixture that may contain acids, organic chemicals, soil or dust. Size of the particle is directly related to the particles potential to cause negative health effects.
The EPA groups PM into two categories: PM10 and PM2.5.
PM10 is between 2.5 and 10microns in size, an example could be dust.
PM2.5 are 2.5 microns in diameter and are referred to as fine particles. An example could be particles emitted from forest fires.
Exposure to PM can lead to airway irritation, difficulty breathing, decreased lung function, aggravation of asthma, irregular heartbeat and heart attacks.
Effects of PM on the environment include reduced visibility, increased sedimentation in water bodies, depletion of nutrients in the soil.

Question 24

Effects and explanation of Sulfur Oxides

Answer 24

Fossil fuel combustion accounts for 73% of Sulfur Oxides (SOx) emissions. Other industrial sources account for 20% of SOx emission. Sulfur oxides are highly soluble and are absorbed in the upper respiratory system where they irritate and constrict the airways. SOx is significantly more harmful when it absorbs particulate matter forming an an aerosol.

Question 25

What are Hazardous Air Pollutants (HAPs)?

Answer 25

The EPA has developed 188 compounds in addition to the six priority air pollutants that are potentially carcinogenic, mutagenic, or teratogenic.
Anthropogenic activities are responsible for most HAP emissions.

Question 26

What is the toxic release inventory program?

Answer 26

The toxic release inventory program (TRI) is an EPA program that provides information on economic analysis, risk, and pollution prevention information in an effort to help industry decrease annual emission of toxic compounds.

Question 27

What groups of air pollution control devices exist and why?

Answer 27

Air pollution control devices are divided into two groups: those for controlling particulates and those for controlling gaseous pollutants. This is due to the difference in size of the pollutants.

Question 28

How is removal efficiency calculated?

Answer 28

removal efficiency (%) = (amount of pollutant collected by the treatment device per unit time (kg/s)) / (amount of pollutant entering the device per unit time (kg/s))

Question 29

What factors contribute to stationary pollutant sources as major or minor?

Answer 29

In part, this major or minor status depends on the mass emission rate of a particular pollutant and the geographic location of the source.
That is to say, if the source is located in an area that does not already meet the current NAAQS goals, it will be subject to harsher standards than if it were in a region that was did meet NAAQS goals for that area.

Question 30

What is BACT?

Answer 30

Best available control technology

Question 31

What is the threshold for regulation of Hazardous Air Pollutants (HAP) by NESHAP (national emission standards for hazardous air pollutants)?

Answer 31

Any new construction or reconstructed facility that emits 100ton/year or more of a listed HAP OR 35 tons/year of any combination of HAPs must comply with the control standards specified in the NESHAP.

Question 32

What is LAER?

Answer 32

Lowest achievable emission rate (LAER)
LAER is an option to projects that do not have alternative sites available to move to and are located in areas where ambient pollution levels exceed NAAQS

Question 33

Regulated compounds are grouped into three categories, what are they.

Answer 33

Inorganic compounds including sulfur oxide, nitrogen oxides, and carbon monoxide - all primary pollutants.
Particulate Matter including lead particulates - a priority pollutant.
Organic compounds including VOC’s which are regulated like priority pollutants because they are a precursor to ozone

Question 34

What critical information is needed to determine if pollutant control devices are required?

Answer 34

The concentration of pollutants and the volumetric airflow of the waste air stream must be determine.

Question 35

What critical information is needed to determine if pollutant control devices are required?

Answer 35

The concentration of pollutants and the volumetric airflow of the waste air stream must be determine.