IELTS Reading: Indoor Pollution – Answer Key & Detailed Analysis

Many people believe that home is the safest sanctuary, shielding us from the pollution of the outside world. However, the IELTS reading passage “Indoor Pollution” presents an alarming perspective: everyday activities like bathing, washing, and cooking can actually be sources of toxic chemicals released into our indoor air.

In this article, the ECE language center provides an in-depth analysis of this complex reading passage, offering answers, detailed explanations, and key vocabulary to help you not only excel in your exam but also gain insight into a critical health issue.

Detailed Reading Passage and Questions: Indoor Pollution

Reading Content

(Paragraph 1) Since the early eighties, we have been only too aware of the devastating effects of large-scale environmental pollution. Such pollution is generally the result of poor government planning in many developing nations or the short-sighted, selfish policies of the already industrialised countries which encourage a minority of the world’s population to squander the majority of its natural resources.

(Paragraph 2) While events such as the deforestation of the Amazon jungle or the nuclear disaster in Chernobyl continue to receive high media exposure, as do acts of environmental sabotage, it must be remembered that not all pollution is on this grand scale. A large proportion of the world’s pollution has its source much closer to home. The recent spillage of crude oil from an oil tanker accidentally discharging its cargo straight into Sydney Harbour not only caused serious damage to the harbour foreshores but also created severely toxic fumes which hung over the suburbs for days and left the angry residents wondering how such a disaster could have been allowed to happen.

(Paragraph 3) Avoiding pollution can be a full­time job. Try not to inhale traffic fumes; keep away from chemical plants and building sites; wear a mask when cycling. It is enough to make you want to stay at home. But that, according to a growing body of scientific evidence, would also be a bad idea. Research shows that levels of pollutants such as hazardous gases, particulate matter and other chemical ‘nasties’ are usually higher indoors than out, even in the most polluted cities. Since the average American spends 18 hours indoors for every hour outside, it looks as though many environmentalists may be attacking the wrong target.

(Paragraph 4) The latest study, conducted by two environmental engineers, Richard Corsi and Cynthia Howard-Reed… suggests that it is the process of keeping clean that may be making indoor pollution worse. The researchers found that baths, showers, dishwashers and washing machines can all be significant sources of indoor pollution, because they extract trace amounts of chemicals from the water that they use and transfer them to the air.

(Paragraph 5) Nearly all public water supplies contain very low concentrations of toxic chemicals… Dr. Corsi wondered whether they stay there when water is used, or whether they end up in the air that people breathe. The team conducted a series of experiments…

(Paragraph 6) The degree to which the most volatile elements could be removed from the water, a process known as chemical stripping, depended on a wide range of factors, including the volatility of the chemical, the temperature of the water… Dishwashers were found to be particularly effective: the high-temperature spray… results in a nasty plume of toxic chemicals that escape…

(Paragraph 7) In fact, in many cases, the degree of exposure to toxic chemicals in tap water by inhalation is comparable to the exposure that would result from drinking the stuff. This is significant because many people are so concerned about water-borne pollutants that they drink only bottled water, worldwide sales of which are forecast to reach $72 billion by next year.

(Paragraph 8) The aim of such research is not… to encourage the use of gas masks… Instead, it is to bring a sense of perspective to the debate about pollution. According to Dr Corsi, disproportionate effort is wasted campaigning against certain forms of outdoor pollution, when there is as much or more cause for concern indoors…

(Paragraph 9) …Overcrowded classrooms whose ventilation systems were designed for smaller numbers of children frequently contain levels of carbon dioxide that would be regarded as unacceptable… ‘New car smell’ is the result of high levels of toxic chemicals, not cleanliness.

(Paragraph 10) The implications of indoor pollution for health are unclear. But before worrying about the problems caused by large-scale industry, it makes sense to consider the small-scale pollution at home and welcome international debate about this. Scientists investigating indoor pollution will gather next month in Edinburgh at the Indoor Air conference to discuss the problem.

Questions

Questions 1-6 (Multiple Choice)

1. In the first paragraph, the writer argues that pollution …….

A. has increased since the eighties.

B. is at its worst in industrialised countries.

C. results from poor relations between nations.

D. is caused by human self-interest.

2. The Sydney Harbour oil spill was the result of a …….

A. ship refuelling in the harbour.

B. tanker pumping oil into the sea.

C. collision between two oil tankers.

D. deliberate act of sabotage.

3. In the 3rd paragraph, the writer suggests that …….

A. people should avoid working in cities.

B. Americans spend too little time outdoors.

C. hazardous gases are concentrated in industrial suburbs.

D. there are several ways to avoid city pollution.

4. The Corsi research team hypothesised that …….

A. toxic chemicals can pass from air to water.

B. pollution is caused by dishwashers and baths.

C. city water contains insufficient chlorine.

D. household appliances are poorly designed.

5. As a result of their experiments, Dr Corsi’s team found that …….

A. dishwashers are very efficient machines.

B. tap water is as polluted as bottled water.

C. indoor pollution rivals outdoor pollution.

D. gas masks are a useful protective device.

6. Regarding the dangers of pollution, the writer believes that …….

A. there is a need for rational discussion.

B. indoor pollution is a recent phenomenon.

C. people should worry most about their work environment.

D. industrial pollution causes specific diseases.

Questions 7-13 (Matching Cause and Effect) Match each Cause (Questions 7-13) in List A with its Effect (A-J) in List B.

List A: CAUSES

7. Industrialised nations use a lot of energy.

8. Oil spills into the sea.

9. The researchers publish their findings.

10. Water is brought to a high temperature.

11. People fear pollutants in tap water.

12. Air conditioning systems are inadequate.

13. Toxic chemicals are abundant in new cars.

List B: EFFECTS

A. The focus of pollution moves to the home.

B. The levels of carbon monoxide rise.

C. The world’s natural resources are unequally shared.

D. People demand an explanation.

E. Environmentalists look elsewhere for an explanation.

F. Chemicals are effectively stripped from the water.

G. A clean odour is produced.

H. Sales of bottled water increase.

I. The levels of carbon dioxide rise.

J. The chlorine content of drinking water increased.

Summary of the Reading Passage

The “Indoor Pollution” passage argues that while society focuses on large-scale outdoor pollution, the real danger may be even greater right inside our own homes. The author points out that indoor pollution levels are often higher than those outdoors. A study by Corsi and Howard-Reed found that daily cleaning activities like bathing, dishwashing, and laundry are significant sources of toxic chemicals being transferred from water into the air.

The article also mentions other indoor pollution sources such as gas stoves, candles, poor ventilation, and the “new car smell.” Ultimately, the author calls for a more rational and balanced debate on pollution, emphasizing the need to address indoor pollution before worrying about large-scale industrial issues.

Key Vocabulary and Structures

1. Squander (verb): To waste (resources, money).
2. Particulate matter (noun phrase): Microscopic solid or liquid matter suspended in the atmosphere (e.g., fine dust).
3. Trace amounts (noun phrase): Very small, barely detectable quantities.
4. Volatile (adjective): Easily evaporated at normal temperatures.
5. Chemical stripping (noun phrase): The process of removing chemicals from a substance.
6. Disproportionate (adjective): Out of proportion; too large or too small in comparison to something else.
7. Noxious (adjective): Harmful, poisonous, or very unpleasant.

Answers and Detailed Explanations

Questions 1-6

1. D. is caused by human self-interest.

• Evidence (Paragraph 1): “…the short-sighted, selfish policies…”
• Explanation: “Selfish policies” is synonymous with “human self-interest.”

2. B. tanker pumping oil into the sea.

• Evidence (Paragraph 2): “…an oil tanker accidentally discharging its cargo straight into Sydney Harbour…”
• Explanation: “Discharging its cargo” refers to the act of pumping oil into the sea.

3. D. there are several ways to avoid city pollution.

• Evidence (Paragraph 3): “Try not to inhale traffic fumes; keep away from chemical plants and building sites; wear a mask when cycling.”
• Explanation: The paragraph lists a series of actions to avoid pollution, which are “several ways.”

4. B. pollution is caused by dishwashers and baths.

• Evidence (Paragraph 4): “The researchers found that baths, showers, dishwashers and washing machines can all be significant sources of indoor pollution…”
• Explanation: This was the team’s finding, which served as the hypothesis they set out to test.

5. C. indoor pollution rivals outdoor pollution.

• Evidence (Paragraph 8): “…there is as much or more cause for concern indoors…”
• Explanation: The phrase “as much or more” indicates that indoor pollution is just as concerning as (“rivals”) outdoor pollution.

6. A. there is a need for rational discussion.

• Evidence (Paragraph 10): “…it makes sense to consider the small-scale pollution at home and welcome international debate about this.”
• Explanation: “Debate” is synonymous with “discussion.” The author believes a discussion on this issue is necessary.

Questions 7-13

7. C. The world’s natural resources are unequally shared.

• Evidence (Paragraph 1): “…industrialised countries which encourage a minority of the world’s population to squander the majority of its natural resources.”
• Explanation: The fact that a minority wastes the majority of resources indicates that they are shared unequally.

8. D. People demand an explanation.

• Evidence (Paragraph 2): “…left the angry residents wondering how such a disaster could have been allowed to happen.”
• Explanation: Angry residents wondering how a disaster happened is a form of demanding an explanation.

9. A. The focus of pollution moves to the home.

• Explanation: This is an inference. The entire study and its publication (as mentioned in paragraph 4) aim to shift public and scientific attention from outdoor to indoor pollution.

10. F. Chemicals are effectively stripped from the water.

• Evidence (Paragraph 6): “The degree to which the most volatile elements could be removed from the water, a process known as chemical stripping, depended on… the temperature of the water…”
• Explanation: High water temperature is a factor that facilitates the “chemical stripping” process.

11. H. Sales of bottled water increase.

• Evidence (Paragraph 7): “…many people are so concerned about water-borne pollutants that they drink only bottled water, worldwide sales of which are forecast to reach $72 billion…”
• Explanation: Fear of tap water pollutants is the direct cause of people buying bottled water.

12. I. The levels of carbon dioxide rise.

• Evidence (Paragraph 9): “Overcrowded classrooms whose ventilation systems… frequently contain levels of carbon dioxide that would be regarded as unacceptable…”
• Explanation: Inadequate ventilation systems are the cause of increased CO2 levels.

13. G. A clean odour is produced.

• Evidence (Paragraph 9): “‘New car smell’ is the result of high levels of toxic chemicals…”
• Explanation: The “new car smell,” often perceived as a “clean” scent, is actually produced by toxic chemicals.

Conclusion

The “Indoor Pollution” passage is not just an IELTS Reading exercise; it is a wake-up call regarding the hidden health risks within our own homes.

In terms of skills, this passage is a classic example of testing your ability to infer and link ideas that are not explicitly stated. Understanding that “fear of tap water pollutants” (cause) leads to “buying bottled water” (effect) is key to mastering Cause-Effect questions.

We hope that through these detailed analyses from ECE, you have not only grasped the answers but also equipped yourself with the logical thinking necessary to confidently tackle even the most complex reading passages.