Respiratory Diseases Associated with Pollutants (L23)

Question 1

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Particulate Matter.

Answer 1

Airborne particulate matter is made up of a collection of solid and/or liquid materials of various sizes.

These particles range in size from a hundred nanometres in diameter (ultrafine) or less up to around 100 microns (100um)

Different names are used for different types and they are defined by particle size or sampling method.

TSP – Total suspended particulates
PM10 and PM2.5 (relates to the mean aerodynamic diameter)
Ultra fine particles (<0.1 um diameter)
BS (black smoke) and BC (black carbon).

PM consists of primary components which are released directly from the source and secondary components which are formed in the atmosphere by chemical reactions.

They are normally classified according to their aerodynamic properties as these govern their deposition within the lung and the transport and removal of these particles from the air.

In general smaller particles (PM10 and smaller) and combustion related particles are more important for health effects.

Question 2

List the primary components of particulate matter.

Answer 2

Sodium Chloride - Sea Salt

Elemental Carbon - High temperature combustion of fossil fuel

Trace Metals - Generated from metallurgical processes or as impurities mixed into fuels

Mineral Components - From quarrying

Question 3

List the secondary components of particulate matter.

Answer 3

Sulphate - formed by oxidation of sulphur dioxide in the atmosphere

Nitrate - Oxidation of nitrogen oxides

Question 4

In urban areas typical annual mean exposure levels of PM are __ – 40 ugm-3. In rural areas this is 0-__um-3.

Answer 4

10.

Question 5

List some man-made sources of particulate matter.

5

Answer 5

• Road Transport
• Non-combustion processes
• Industrial combustion plants
• Commercial and residential combustion
• Public power generation

Question 6

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The current particulate matter paradigm.

Answer 6

1) Combustion derived components of PM10 which are ultrafine and can be metal and polycyclic aromatic hydrocarbon (PAH) rich are most likely to be the harmful component.
2) Oxidative stress arising from these particles and their associated metals and organics elicits inflammation which drives the local and cardiovascular effects.
3) The adverse effects are only seen in susceptible groups whose pre-existing lung or heart disease makes them more likely to succumb to the very low extra inflammation that they get from the particulate matter.

Question 7

Both short term and long term exposure to PM2.5 are associated with respiratory and cardiovascular illness and mortality.

Long term exposure to PM2.5 is associated with increased levels of cardiovascular and respiratory diseases. Best estimates indicate a __% increase in death rates per 10 ug m-3 PM2.5 concentration.

Answer 7

6.

Question 8

List what exposure to PM increases.

5

Answer 8

• The risk of respiratory death in infants under 1 by affecting the rate of lung function development.
• Aggravates asthma and causes other respiratory symptoms such as cough and bronchitis in children.
• Increased risk of the development of lung cancer (particularly in men).
• Seriously affects health, increasing deaths from cardiovascular and respiratory diseases.
• Increases morbidity, as indicated by hospital admissions for respiratory diseases.

Question 9

Recent evidence from murine studies has shown the effect of ultrafine particles on the development of cardiovascular disease.

Animals were exposed to concentrated ultrafine particles, concentrated particle

Answer 9

Mice exposed to ultrafine particles exhibited significantly larger atherosclerotic lesions than mice exposed to filtered air or larger particles. These mice also showed evidence of greater systemic oxidative stress.

Question 10

Sulphur dioxide is readily soluble in water where it dissolves to form sulfurous acid (H2SO3).

Because of its acidic properties even moderate concentrations can cause _____ in both asthmatics and normal adults.

Answer 10

Bronchoconstriction.

Question 11

Sulphur Dioxide is produced when material or fuel containing sulphur is burned.

Globally most sulphur dioxide comes from natural sources but in the UK the predominant source is power stations burning ___1___ and heavy ___2___ (91%).

Answer 11

1. Coal

2. Oils

Question 12

Nitrogen oxide (NO) is mainly derived from road transport emissions and other \_\_\_1\_\_\_ processes. 
NO is not harmful to health, however, once released into the atmosphere it is rapidly oxidised to \_\_\_2\_\_\_ which is harmful to health.

Answer 12

1. Combustion

2. NO2

Question 13

Long term exposure to ___1___ decreases lung function and increases the risk of acute ___2___ and cough, particularly in children.

Several studies have shown that ___1___ exposure increases allergic responses to inhaled pollens.

Individual with ___3___ and children are considered to be most vulnerable to exposure.

There is no evidence of a threshold of exposure for either long term or short term exposure.

There is some evidence that exposure to ___1___ is associated with cardiovascular mortality and morbidity.

Answer 13

1. NO2
2. Bronchitis
3. Asthma

Question 14

Ozone (O3) is formed by a complicated series of reactions initiated by ___1___.

High in the atmosphere ozone forms a shield that protects the earth from ___2___.

At ground level it is a major pollutant with concentrations often being high in busy urban centres on sunny days in summer.

Ozone appears to have affects on health independently of other pollutants.

Short term exposure to ozone cause ___3___ and increase the susceptibility to inhaled allergens.

Long term exposure to relatively low concentrations can reduce ___4___ function.

Answer 14

1. Sunlight
2. UV
3. Bronchoconstriction
4. Lung

Question 15

Since the introduction of unleaded petrol there has been a significant decrease in urban lead levels.
Even small amounts of lead can be harmful, especially to infants and young children. In addition lead taken in by pregnant women can affect the unborn child. Exposure has been linked to _____ mental function, visual-motor performance and neurological damage.

Answer 15

Impaired.

Question 16

Acute exposure to mercury or mercury containing compounds can affect the respiratory and ___1___ systems. ___2___ mercury can cross the blood brain barrier and cause irreversible nervous system and brain damage.

Answer 16

1. Gastrointestinal

2. Organic

Question 17

____ 1 ____ is a colourless, odourless poisonous gas produced by the incomplete, or inefficient, ___2___ of fuel.

It is not an irritant thus it is an insidious disease.

____ 1 ____ has a 300 x greater affinity for Hb than O2. The reaction with Hb is reversible (In presence of high levels of O2 HbCO => HbO2).

Answer 17

1. Carbon Monoxide

2. Combustion

Question 18

One of the most striking signs of _____ _____ poisoning is the cherry red appearance of the face.

Answer 18

Carbon monoxide.

Question 19

Describe the symptoms of persons poisoned by carbon monoxide at:

Low dose?
Moderate dose?
High dose?
Very high dose?

Answer 19

Low dose = Fatigue in healthy people and chest pain in those with heart disease.

Moderate dose = Impaired vision and co-ordination, headaches, dizziness, nausea,vomiting, memory loss and flu like symptoms.

High dose = Loss of consciousness on exercise.

Very high dose = Loss of consciousness. Death.

Question 20

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Effects of different levels of carbon monoxide saturation.

Answer 20

0-10% saturation Hb
- No symptoms

10-20% saturation Hb
- Tightness in forehead, flushed skin, yawning

20-30% saturation Hb
- Headache, dizziness, palpitations on exercise

30-40% saturation of Hb
- Severe headache, weakness, dizziness, nausea

40-50% saturation of Hb
- As above with increased respiratory and pulse rate

50-60% saturation Hb
- Coma

60-70% saturation Hb
- Coma, weakened breathing, death imminent

70-80% saturation Hb
- Respiratory failure, death

90% saturation Hb - Immediate death

Question 21

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Radon.

Answer 21

Radon is the second leading cause of lung cancer (6-15% of lung cancers).

Naturally occurring - resulting from the decay of radium.

Radon 222 breaks down into radon decay products (Polonium, lead and bismuth).

The breakdown in radon is accompanied by the emission of an alpha particle.

After inhalation radon can decay and release alpha particles,

Alpha particles penetrate cells of the lung epithelium and cause cancer.

Most of radon is exhaled before it decays. A small part of the inhaled radon and its progeny may be transferred from the lungs to the blood and finally other organs but the doses are so low that the associated cancer risk is negligible.

The average radon concentration outdoors varies between 5 and 15 Bq/m3 (where 1 Becquerel corresponds to the transformation of one atomic nucleus per second).

The risk of lung cancer increases 16% per 100 Bq/m3.

Thus the risk of lung cancer by the age of 75 in a non smoker exposed to 0, 100 and 400 Bq/m3 will be about 4, 5 and 7 in 1000.

However for smokers the risk for lung cancer is about 25 times greater, namely 100, 120 and 160 in 1000 respectively.

Question 22

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Psittacosis.

Answer 22

Psittacosis is an infection caused by the intracellular bacterium Chlamydophila psittaci.

This bacterium infects parrots, parakeets, canaries etc.

Psittacosis is an occupational disease in zoos and pet shop employees.

Human to Human transmission is rare.

Chlamydophila psittaci (previously Chlamydia psittaci) is a Gram-negative bacterium that lacks a cell wall. This organism proliferates intracellularly. Signs of disease in birds can be acute such as diarrhea, loss of appetite, respiratory complications or chronic e.g, tremors, and convulsions. Death also may occur. The disease is transmitted among birds by inhalation of aerosolized faecal contents, aerosolized particles produced by sneezing, or by exposure to a bird owner’s contaminated clothing.

Zoonotic transmission from birds to humans can result in flu-like symptoms such as coughing, muscle aches, fever, chills, and headache.

Psittacosis can be transmitted from birds to humans by direct contact, inhalation of dried bird droppings and feather dust, bites, mouth-to-beak contact, and handling of infected birds

In untreated cases mortality can reach 50%. Antibiotic therapy can reduce this to 1% (Doxycycline).

Question 23

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Aspergillosis.

Answer 23

Aspergillus species are ubiquitous moulds of organic matter.

Aspergillus may cause a range of diseases in humans ranging from hypersensitivity reactions to aspergilloma.

An aspergilloma (mycetoma) is a fungus ball that develops in a pre-existing cavity in the lung. This may be caused by tuberculosis, cystic fibrosis, emphysema.

The ball of fungus may move in the cavity but will not invade the cavity wall, however it may cause haemoptysis.

2 types:

Allergic bronchopulmonary aspergillosis (ABPA)
- Type III hypersensitivity reaction to A. fumigatus. Early on the response causes bronchoconstriction but as the inflammation continues permanent damage occurs. Symptoms – wheeze and cough

Invasive Aspergillosis
- Occurs in HIV infection or some autoimmune diseases. Commonly seen in the lung but may be found in other organs.

Question 24

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Mycotoxins.

Answer 24

Mycotoxicosis is a toxic reaction after exposure of plants and animals to a number of fungal metabolites.

Mycotoxin exposure in humans usually follows oral ingestion of grains and seeds that a fungus has used as a substrate for growth (ergotism).

These mycotoxins may also cause hepatitis and hepatocellular carcinoma.

A second potential route of exposure to mycotoxin is through inhalation. Certain occupations eg. Agriculture and textile work are at increased risk of pulmonary mycotoxosis (PM).

PM presents as fever, chills, dyspnea and myalgia about 4-6 hours after exposure to contaminated dusts.

PM resembles immunologically mediated lung diseases but there is no need for prior sensitization.

It has been suggested that PM may be a cause of interstitial lung disease.