Chapter 10: Air Pollution

Question 1

What are the four main pollutants that comprise smog?

Answer 1

Particulate matter, ozone (O3), nitric oxides (e.g., NO2), and sulfur oxides (e.g., SO2).

Question 2

What are the four main factors that contribute to acute lung injury?

Answer 2

Oxidative Damage
Airway Reactivity
Pulmonary Edema
Cell proliferation

Question 3

How can oxidative damage lead to acute lung injury?

Answer 3

Ozone, NO2, tobacco smoke, and lung immune system cells can all generate reactive oxygen species (ROS), causing oxidative damage to the lungs.

Question 4

How do air pollutants contribute to acute lung injury?

Answer 4

Air pollutants can trigger bronchoconstriction, which limits oxygen uptake and can be particularly problematic for individuals with asthma.

Question 5

What happens during pulmonary edema in acute lung injury?

Answer 5

Extensive cellular damage in the lungs can cause fluid to leak into alveolar spaces, leading to pulmonary edema and less efficient oxygen exchange.

Question 6

Why is cell proliferation a concern in acute lung injury?

Answer 6

Epithelial cells can proliferate in response to lung injury, and excessive cell division can lead to an increased potential for mutations and the development of lung cancer.

Question 7

What are the main types of chronic lung injuries?

Answer 7

The main types of chronic lung injuries are COPD (chronic obstructive pulmonary disorder), fibrosis, asthma, and cancer.

Question 8

What is emphysema and bronchitis in relation to COPD?

Answer 8

Emphysema is the destruction of the alveolar sacs, while bronchitis is constant inflammation of bronchi and excessive mucous deposition. Both conditions are part of COPD.

Question 9

What is fibrosis and how does it affect the lungs?

Answer 9

Fibrosis is an inflammation response that leads to increased deposition of collagen in damaged lungs, making them less elastic and decreasing oxygen exchange.

Question 10

What is asthma and how does it affect the lungs?

Answer 10

Asthma is a condition that causes recurrent bronchoconstriction, limiting oxygen uptake. This can be especially problematic for people with asthma.

Question 11

How does chronic lung injury lead to cancer?

Answer 11

Chronic lung injury can lead to cancer through direct DNA mutations from oxidative damage and indirect DNA mutations from excessive cell division to replace damaged cells.

Question 12

What are some possible mechanisms of toxicity associated with particulate matter?

Answer 12

• Leads to lung irritation which leads to an increase in permeability in lung tissue.
• Increases susceptibility to viral and bacterial pathogens leading to pneumonia in vulnerable persons who are unable to clear these infections.
• Aggravates the severity of chronic lung diseases causing decreased lung function.
• Causes inflammation of lung tissue, resulting in the release of chemicals that impact heart function.
• Causes changes in blood chemistry that can contribute to heart attacks.

Question 13

What is the primary source of nitrogen dioxide (NO2) in urban areas?

Answer 13

The primary source of nitrogen dioxide (NO2) in urban areas is automobile exhaust.

Question 14

What causes NO2 to hydrolyze and potentially cause chemical pneumonitis?

Answer 14

NO2 hydrolyzes to nitrous (HNO2) and nitric (HNO3) acid, which can then cause chemical pneumonitis.

Question 15

What is the threshold level of NO2 exposure that can cause lung irritation, especially in the terminal bronchioles?

Answer 15

The threshold level of NO2 exposure that can cause lung irritation, especially in the terminal bronchioles, is 8 pphm (0.08 ppm).

Question 16

What is the acute damage threshold level for NO2 exposure?

Answer 16

The acute damage threshold level for NO2 exposure is 75 to 100 ppm.

Question 17

Does urban air typically exceed the acute damage threshold level for NO2 exposure?

Answer 17

No, urban air rarely exceeds the acute damage threshold level for NO2 exposure.

Question 18

What is the most acutely toxic air pollutant?

Answer 18

Ozone (O3) is the most acutely toxic of common air pollutants.

Question 19

What is the process that creates large quantities of ozone?

Answer 19

Large quantities of ozone are created through the photolysis of NO2, which leads to the creation of O* and NO, followed by the reaction of O with O2 to form O3.

Question 20

At what level does lung damage begin for ozone exposure?

Answer 20

Lung damage begins at 0.2 ppm of ozone.

Question 21

At what level do cells begin dying due to ozone exposure?

Answer 21

Cells begin dying at 0.8 ppm of ozone, which is equivalent to 80pphm.

Question 22

What are the sources of sulfur dioxide (SO2)?

Answer 22

Sulfur dioxide (SO2) is emitted from vehicles using high sulfur fuels and from coal combustion.

Question 23

How does sulfur dioxide (SO2) affect the respiratory system?

Answer 23

Sulfur dioxide (SO2) is a “general irritant of respiratory tract” and is hydrated to form sulfurous acid (H2SO3) in the lungs, causing bronchoconstriction and reduced airway flow. It is particularly bad for asthmatics.

Question 24

How does acute exposure to sulfur dioxide (SO2) affect the lungs?

Answer 24

Acute exposure to sulfur dioxide (SO2) at levels greater than 250 ppm causes direct cellular injury in lungs.

Question 25

What are the effects of long-term exposure to sulfur dioxide (SO2) at levels less than 1 ppm?

Answer 25

Long-term exposure to sulfur dioxide (SO2) at levels less than 1 ppm leads to bronchoconstriction, bronchitis, and higher susceptibility to infections, but no direct lung cell damage.

Question 26

Where is sulfur dioxide (SO2) primarily absorbed in the body?

Answer 26

Sulfur dioxide (SO2) is absorbed primarily in nasal passages and bronchi.

Question 27

What are asbestos and where are they used?

Answer 27

Asbestos are a group of silicate minerals in fiber form. They are used as insulation and in fire retardant materials, and as a component of brake pads.

Question 28

How do asbestos fibers affect the lungs?

Answer 28

When larger asbestos fibers are inhaled, they get consumed by lung macrophages, which cannot leave the lungs. The fibers then initiate an inflammation response, which causes high turnover of alveolar cells. This may eventually lead to cancer.

Question 29

What type of cancer is caused by asbestos exposure?

Answer 29

Asbestos exposure causes mesothelioma, which is a unique cancer. Therefore, it is relatively easy to attribute cancer deaths to asbestos.

Question 30

Which country was the largest producer and exporter of asbestos, and what happened after its use was banned in that country?

Answer 30

Canada was the largest producer and exporter of asbestos. Even after its use was banned in Canada, it was still exported to other countries, such as Bangladesh, India, Indonesia, and Thailand.