This set of Pollution Control Multiple Choice Questions & Answers (MCQs) focuses on “Effects of Air Pollutants on Human Health – Set 3”.
1. Which of the following is not a factor on which the effects of gaseous pollutants are dependant on?
a) Exposure time
b) Concentration of pollutants
c) Soluble nature of the pollutant
d) Atmospheric characteristics
View Answer
Explanation: Aerosols all the given options, except for atmospheric characteristics, are all factors upon which the effects of gaseous pollutants depend. All the determinants are also correlated.
2. Where do highly soluble gases deposit in the respiratory tract?
a) Nose
b) Upper respiratory tract
c) Lower respiratory tract
d) Lungs
View Answer
Explanation: Highly soluble gases get absorbed by the upper respiratory system. They are retained in the respiratory tract because of their high solubility. An example of highly soluble gas is sulphur dioxide.
3. Which of part of the respiratory system do sparingly soluble gaseous pollutants get deposited?
a) Nose
b) Upper respiratory system
c) Lower respiratory system
d) Lungs
View Answer
Explanation: The lesser soluble it is, the farther the gas penetrates in the respiratory system. So, sparingly soluble gases can reach the lungs. Examples of such gases are carbon monoxide and nitrogen dioxide.
4. At what concentration of exposure to sulphur dioxide do humans experience broncho-constriction?
a) 1.6 ppm
b) 9 ppm
c) 10 ppm
d) 20 ppm
View Answer
Explanation: Effects of sulphur dioxide are different at different levels of exposure. In the condition of broncho-constriction, the bronchi muscles contract. The concentration at which it occurs is as low at 1.6 ppm.
5. Where is 95% of the total sulphur dioxide retained?
a) Upper respiratory tract
b) Lower respiratory tract
c) Lungs
d) Nose
View Answer
Explanation: Sulphur dioxide is highly soluble in water and gets retained in the upper respiratory system. About 95% of it gets absorbed here. The rest may progress further and may even reach the lungs.
6. At what level of exposure to sulphur dioxide is throat irritation is an effect of sulphur dioxide?
a) 1.6 ppm
b) 9 ppm
c) 15 ppm
d) 20 ppm
View Answer
Explanation: For throat irritation to manifest, the concentration of exposure has to be between 8 and 12 ppm. The only option that falls in this range is 9 ppm. Throat irritation is a short-term effect of exposure.
7. Sulphur dioxide is more harmful than sulphates.
a) False
b) True
View Answer
Explanation: Sulphur dioxide is absorbed by the upper respiratory tract, and it is not as much of a threat as its aerosol counterparts. Sulphates, and even sulphuric acid, formed in the atmosphere may reach the lungs where it can have chronic health effects.
8. What is an alternate way sulphur dioxide can enter the lungs?
a) As a gas
b) As sulphuric acid
c) Absorbed by salts
d) As a liquid
View Answer
Explanation: Sulphur dioxide’s primary mode of entrance into the body is as a gas. An alternative method would be by being absorbed by aerosols of metals and their salts. Sulphuric acid formation occurs in the lungs.
9. At what concentration of exposure to sulphur dioxide, does eye irritation occur?
a) 5 ppm
b) 9 ppm
c) 10 ppm
d) 20 ppm
View Answer
Explanation: Symptoms of exposure to sulphur dioxide manifest differently depending upon the concentration of exposure. Eye irritation occurs at about 10 ppm concentration of sulphur dioxide. At 9 ppm, throat irritation occurs, and at 20 ppm coughing occurs.
10. What is a chronic effect of exposure to sulphur dioxide?
a) Respiratory infection
b) Cough
c) Eye irritation
d)Throat irritation
View Answer
Explanation: A chronic effect of exposure to low concentrations of sulphur dioxide is respiratory infections, especially in children. The other given options like eye and throat irritation are short-term effects.
11. Which of the following statements about carbon monoxide is untrue?
a) It is an asphyxiant
b) It gets absorbed by the upper respiratory tract
c) It combines with the blood
d) Exposure to it can cause cardiovascular disease
View Answer
Explanation: Carbon monoxide does not get absorbed by the upper respiratory tract. It is because it is sparingly soluble in water, and manages to reach as far as the alveoli, where it diffuses into the blood.
12. How much more affinity does carbon monoxide have towards haemoglobin than oxygen?
a) 60 times
b) 110 times
c) 160 times
d) 210 times
View Answer
Explanation: Carbon monoxide has more affinity towards haemoglobin than oxygen, about 210 more times. Due to this, carbon monoxide gets absorbed by the cells instead of oxygen, causing asphyxiation.
13. What is the equilibrium level of carboxyhaemoglobin, if the body is exposed to 10 ppm of carbon monoxide?
a) 2.1%
b) 1.5%
c) 0.5%
d) 0.16%
View Answer
Explanation: Given, the concentration of CO = 10 ppm
%COHb in the blood = (concentration of CO, ppm) * 0.16 + 0.5
Therefore, %COHb in the blood = 10 * 0.16 + 0.5 = 2.1%
14. For an urban air concentration of 10 ppm to 40 ppm of carbon dioxide, what is the COHb concentration in the blood?
a) 10% to 40%
b) 2% to 7%
c) 1% to 3%
d) It is difficult to say
View Answer
Explanation: For a concentration of 10 ppm to 40 ppm in urban air, the percentage of COHb (carboxy haemoglobin) in the blood is between 2% and 7%. This concentration takes approximately 8 hours to present.
15. What concentration of COHb can be fatal if left untreated?
a) 40-50%
b) 50-60%
c) 60-70%
d) 70-80%
View Answer
Explanation: Concentrations of COHb (carboxy haemoglobin) of 60% to 70% can lead to a coma, which can be fatal if it remains untreated. 40-50% can lead to collapse, 50-60% can lead to treatable coma.
Sanfoundry Global Education & Learning Series – Pollution Control.
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