The IELTS Reading test assesses your ability to locate specific information, understand scientific explanations, recognise paraphrased ideas, and identify relationships between different points in a passage.
Indoor Pollution Reading Answers is based on a passage about indoor air pollution, its common sources, and research into chemicals released during water use. It contains Multiple Choice Questions and Matching Features questions that test your ability to locate information, identify paraphrases, and understand cause-and-effect relationships.
Use this answer key for the Indoor Pollution reading to check your answers for the IELTS reading test:
Question
Answer
1
D
2
B
3
D
4
B
5
C
6
A
7
C
8
D
9
A
10
F
11
H
12
I
13
G
After checking your answers, use this practice page to test how well you can locate information, understand the main ideas, identify paraphrased details, and follow cause-and-effect relationships in the Indoor Pollution passage.
Indoor Pollution IELTS Reading Passage for Practice
This IELTS reading passage examines pollution on a smaller scale, focusing on the air inside homes and buildings. It moves from general environmental pollution to research on household activities and the possible effects of indoor pollutants.
Indoor Pollution
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 industrialized 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 full-time 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, of the University of Texas in Austin, and published in Environmental Science and Technology, 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, most of them left over from the otherwise beneficial process of chlorination. 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 in which known quantities of five such chemicals were mixed with water and passed through a dishwasher, a washing machine, a shower head inside a shower stall or a tap in a bath, all inside a specially designed chamber. The levels of chemicals in the effluent water and in the air extracted from the chamber were then measured to see how much of each chemical had been transferred from the water into the air.
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 and the surface area available for transfer. Dishwashers were found to be particularly effective: the high-temperature spray, splashing against the crockery and cutlery, results in a nasty plume of toxic chemicals that escapes when the door is opened at the end of the cycle.
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. Dr. Corsi’s results suggest that they are being exposed to such pollutants anyway simply by breathing at home.
Paragraph 8
The aim of such research is not, however, to encourage the use of gas masks when unloading the washing. 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 and right under people’s noses.
Paragraph 9
Using gas cookers or burning candles, for example, both result in indoor levels of carbon monoxide and particulate matter that are just as high as those to be found outside, amid heavy traffic. Overcrowded classrooms whose ventilation systems were designed for smaller numbers of children frequently contain levels of carbon dioxide that would be regarded as unacceptable on board a submarine. ‘New car smell’ is the result of high levels of toxic chemicals, not cleanliness. Laser printers, computers, carpets and paints all contribute to the noxious indoor mix.
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. Perhaps unwisely, the meeting is being held indoors.
Indoor Pollution Reading Questions
The reading answers for Indoor Pollution are based on two question types: Multiple Choice Questions and Matching Features. Questions 1–6 require you to select the most suitable option, while Questions 7–13 require you to connect each cause with its corresponding effect.
Before checking the answers, try to locate the relevant paragraph yourself. Pay attention to researchers, household activities, pollutants, scientific findings, environmental examples, and cause-and-effect relationships. The wording of the questions may differ from the passage, so look for meaning rather than only exact keywords.
Questions 1–6: Multiple Choice Questions
Choose the correct option A–D for each question.
Q1. Why does the writer mention deforestation and the Chernobyl disaster in Paragraph 2?
A. To show that environmental disasters are always caused by governments B. To give examples of highly publicised forms of environmental damage C. To explain why indoor pollution has increased D. To compare two different types of nuclear pollution
Q2. What does the research mentioned in Paragraph 3 reveal about indoor environments?
A. They are generally safer than polluted cities. B. They contain fewer chemical pollutants than outdoor areas. C. They can contain higher levels of some pollutants than outdoor areas. D. They are mainly polluted because people spend too much time indoors.
Q3. Why can activities such as showering and washing clothes increase indoor pollution?
A. They release chemicals that were already present in the water into the air. B. They produce additional chemicals through household cleaning products. C. They prevent pollutants from leaving the house through ventilation. D. They increase the amount of chlorine added to public water supplies.
Q4. What was the purpose of the experiments carried out by Corsi and his team?
A. To determine which household appliance used the most water B. To measure how much chemical material moved from water into the air C. To compare bottled water with water from public supplies D. To find out which chemicals were most harmful to humans
Q5. Why are dishwashers particularly effective at removing chemicals from water?
A. They use large quantities of cold water. B. They expose water to a large amount of air. C. They use high-temperature water that splashes against objects. D. They filter the water before it reaches the dishes.
Q6. What is the main purpose of the research discussed in Paragraph 8?
A. To encourage people to stop using household appliances B. To persuade people to wear protective equipment indoors C. To put the issue of pollution into a more balanced perspective D. To prove that outdoor pollution is no longer dangerous
Questions 7–13: Matching Information
Match each statement with the paragraph (A–J) where the information is found.
Paragraphs
A. Paragraph 1 B. Paragraph 2 C. Paragraph 3 D. Paragraph 4 E. Paragraph 5 F. Paragraph 6 G. Paragraph 7 H. Paragraph 8 I. Paragraph 9 J. Paragraph 10
Q7. A comparison is made between the amount of time people spend indoors and outdoors.
Q8. A study examines several household activities that may affect indoor air quality.
Q9. The passage explains that the health effects of indoor pollution are still uncertain.
Q10. The writer describes an environmental incident that caused both physical damage and toxic fumes.
Q11. The passage explains why some people choose bottled water despite the research findings.
Q12. Several everyday products and activities are identified as sources of indoor pollutants.
Q13. The researchers measure chemicals in both water and air after exposing water to household processes.
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Indoor Pollution Reading Answers with Explanation
This section explains all 13 practice questions from the Indoor Pollution passage. Each explanation shows how the answer can be identified from the passage and highlights important keywords and paraphrases that can help with similar IELTS Reading questions.
Answers 1–6: Multiple Choice Questions
These questions test your ability to identify specific details, understand research findings, and recognise the writer’s purpose. Look beyond exact words in the options and match their meaning with the information in the passage.
Q1: Why does the writer mention deforestation and the Chernobyl disaster in Paragraph 2?
Answer: B — To give examples of highly publicised forms of environmental damage.
Explanation: Paragraph 2 mentions the deforestation of the Amazon jungle and the nuclear disaster in Chernobyl as events that continue to receive significant media attention. The writer uses these examples before explaining that pollution can also occur on a much smaller scale.
The purpose is therefore to illustrate major environmental events that attract public attention.
Answer Location: Paragraph 2 Keywords: deforestation, Chernobyl, media exposure, environmental sabotage Paraphrase: “Receive high media exposure” → “are highly publicised” “Events such as” → “examples of”
Q2: What does the research mentioned in Paragraph 3 reveal about indoor environments?
Answer: C — They can contain higher levels of some pollutants than outdoor areas.
Explanation: Paragraph 3 states that pollutants such as hazardous gases and particulate matter are usually higher indoors than outside, even in heavily polluted cities.
This challenges the assumption that staying indoors automatically protects people from pollution.
Q3: Why can activities such as showering and washing clothes increase indoor pollution?
Answer: A — They release chemicals that were already present in the water into the air.
Explanation: Paragraph 4 explains that baths, showers, dishwashers and washing machines can contribute to indoor pollution because they extract trace amounts of chemicals from the water and transfer them to the air.
The chemicals are therefore not necessarily created by these activities. Instead, they are transferred from the water into the surrounding air.
Answer Location: Paragraph 4 Keywords: baths, showers, washing machines, chemicals, transfer, air Paraphrase: “Transfer them to the air” → “release chemicals into the air” “Trace amounts” → “very small quantities”
Q4: What was the purpose of the experiments carried out by Corsi and his team?
Answer: B — To measure how much chemical material moved from water into the air.
Explanation: Paragraph 5 describes experiments in which chemicals were mixed with water and passed through different household systems. The researchers then measured the chemicals in both the effluent water and the air to determine how much had moved from the water into the air.
Therefore, the main purpose was to measure the transfer of chemicals between water and air.
Answer Location: Paragraph 5 Keywords: experiments, chemicals, water, air, measured, transferred Paraphrase: “Transferred from the water into the air” → “moved from water to air” “Levels ... were measured” → “quantities were measured”
Q5: Why are dishwashers particularly effective at removing chemicals from water?
Answer: C — They use high-temperature water that splashes against objects.
Explanation: Paragraph 6 states that dishwashers are particularly effective because their high-temperature spray splashes against crockery and cutlery. This process results in a plume of toxic chemicals escaping when the dishwasher door is opened.
The passage also identifies water temperature and surface area as factors affecting chemical stripping.
Answer Location: Paragraph 6 Keywords: dishwashers, high temperature, spray, splashing, chemical stripping Paraphrase: “High-temperature spray” → “hot water spray” “Chemical stripping” → “removal of chemicals from water”
Q6: What is the main purpose of the research discussed in Paragraph 8?
Answer: C — To put the issue of pollution into a more balanced perspective.
Explanation: Paragraph 8 makes it clear that the research is not intended to encourage people to use gas masks while doing household tasks. Instead, the purpose is to bring a sense of perspective to the pollution debate.
Dr. Corsi argues that too much attention may be given to some forms of outdoor pollution when indoor pollution can also be a significant concern.
Answer Location: Paragraph 8 Keywords: gas masks, perspective, debate, outdoor pollution, indoors Paraphrase: “Bring a sense of perspective” → “consider the issue in a balanced way” “Cause for concern indoors” → “indoor pollution is also important”
Answers 7–13: Matching Information
These questions require you to identify the paragraph containing specific information. The wording in the question may differ from the wording in the passage, so focus on the meaning and key details rather than looking only for identical words.
Q7: A comparison is made between the amount of time people spend indoors and outdoors.
Answer: C — Paragraph 3
Explanation: Paragraph 3 states that the average American spends 18 hours indoors for every hour outside. This directly provides a comparison between the amount of time spent in the two environments.
Answer Location: Paragraph 3 Keywords: 18 hours, indoors, one hour, outside Paraphrase: “18 hours indoors for every hour outside” → “a comparison of indoor and outdoor time”
Q8: A study examines several household activities that may affect indoor air quality.
Answer: D — Paragraph 4
Explanation: Paragraph 4 introduces the study by Richard Corsi and Cynthia Howard-Reed. It identifies baths, showers, dishwashers and washing machines as household activities that can contribute to indoor pollution.
Answer Location: Paragraph 4 Keywords: study, Corsi, Howard-Reed, baths, showers, dishwashers Paraphrase: “Sources of indoor pollution” → “activities that affect indoor air quality”
Q9: The passage explains that the health effects of indoor pollution are still uncertain.
Answer: J — Paragraph 10
Explanation: The opening sentence of Paragraph 10 states that the implications of indoor pollution for health are unclear. The paragraph then mentions an upcoming conference where scientists will discuss the issue.
Answer Location: Paragraph 10 Keywords: health, implications, unclear, scientists, conference Paraphrase: “Implications ... are unclear” → “health effects are uncertain”
Q10: The writer describes an environmental incident that caused both physical damage and toxic fumes.
Answer: B — Paragraph 2
Explanation: Paragraph 2 describes the oil tanker accident in Sydney Harbour. The spilled crude oil caused serious damage to the harbour foreshores and produced toxic fumes that remained over nearby suburbs.
Q11: The passage explains why some people choose bottled water despite the research findings.
Answer: G — Paragraph 7
Explanation: Paragraph 7 explains that many people are concerned about water-borne pollutants and therefore drink only bottled water. However, the research suggests that they may still be exposed to these pollutants by breathing them in at home.
Answer Location: Paragraph 7 Keywords: water-borne pollutants, bottled water, exposure, breathing Paraphrase: “Drink only bottled water” → “choose bottled water instead of tap water” “Being exposed ... by breathing” → “inhaling pollutants”
Q12: Several everyday products and activities are identified as sources of indoor pollutants.
Answer: I — Paragraph 9
Explanation: Paragraph 9 gives several examples, including gas cookers, candles, laser printers, computers, carpets and paints. The paragraph explains that these contribute to the mixture of pollutants found indoors.
Answer Location: Paragraph 9 Keywords: gas cookers, candles, laser printers, computers, carpets, paints Paraphrase: “Contribute to the noxious indoor mix” → “add to indoor pollution”
Q13: The researchers measure chemicals in both water and air after exposing water to household processes.
Answer: E — Paragraph 5
Explanation: Paragraph 5 describes how the researchers mixed chemicals with water and passed the mixture through household systems such as a dishwasher, washing machine, shower and bath tap. They then measured the chemical levels in the effluent water and extracted air.
Answer Location: Paragraph 5 Keywords: chemicals, water, air, experiments, measured, dishwasher, shower Paraphrase: “Levels ... were measured” → “chemical quantities were measured” “Transferred from the water into the air” → “moved from water to air”
How to Approach Indoor Pollution IELTS Reading Questions?
The Indoor Pollution passage combines environmental issues with scientific research and everyday examples. A good approach is to identify the main idea first, then scan for specific details such as researchers, pollutants, household activities, causes, effects, and examples.
Solve Multiple Choice Questions by Eliminating Distractors
For the first six questions, read the question carefully before checking the options. Identify what the question is asking about and then locate the relevant paragraph.
Do not select an option simply because it contains a word from the passage. Some options may use familiar words but change the meaning. Compare the complete idea with the passage before choosing an answer.
For example, when a question asks about Corsi's research, look for information about the research team, household activities, and chemicals, rather than choosing an option simply because it mentions water.
Identify the Main Idea Behind Each Question
Multiple Choice Questions often test the writer's main point rather than one isolated fact.
Ask yourself:
What is the writer trying to explain?
Is the question asking about a cause, effect, opinion or research finding?
Which option represents the complete idea?
Does the passage actually support the option?
This approach can help you avoid choosing an option based on one matching keyword.
Match Causes with Their Effects
Questions 7–13 require you to connect a cause with the correct effect. Start by identifying the important word or phrase in each cause.
Concern about tap-water pollutants → increased bottled-water sales
Toxic chemicals in a new car → characteristic new-car smell
Looking for these relationships makes Matching Features questions easier to manage.
Look for Paraphrased Information
The wording in IELTS questions is often different from the wording in the passage. This is particularly important in the Indoor Pollution passage because several questions describe scientific relationships using simpler language.
For example:
high-temperature water → high-temperature spray
pollutants in tap water → water-borne pollutants
inadequate ventilation → ventilation designed for fewer people
toxic chemicals in a new car → high levels of toxic chemicals causing the new-car smell
Understanding these connections is more useful than searching for identical words.
Follow the Passage Structure
The information in this passage generally develops from broad environmental pollution to specific examples of indoor pollution and then to research findings.
The paragraphs can be roughly tracked as:
Paragraph
Main Focus
1
Large-scale pollution and resource use
2
Sydney Harbour oil spill
3
Outdoor pollution and indoor exposure
4
Corsi and Howard-Reed research
5
Experimental method
6
Chemical stripping and dishwashers
7
Tap-water pollutants and bottled water
8
Indoor versus outdoor pollution
9
Everyday indoor pollution sources
10
Health concerns and need for discussion
This structure can help you return to the right part of the passage without rereading everything.
Check the Context Before Finalising an Answer
After finding a possible answer, read the surrounding sentence or paragraph. This is especially useful when two options appear similar.
For scientific passages, check whether the information refers to the cause, process, result, example, or research finding. A small difference in meaning can change the correct answer.
The Indoor Pollution Reading Answers passage is useful practice for understanding environmental and scientific information in IELTS Reading. It covers outdoor and indoor pollution, household activities, research findings, chemical exposure, and everyday sources of poor indoor air quality.
Working through the passage can help students practise scanning for specific information, understanding cause-and-effect relationships, identifying research findings, recognising paraphrased information, and connecting causes with their effects. Reviewing the explanations after attempting the questions can also help you understand why an answer fits rather than simply memorising the answer key.
For students looking for academic reading answers of indoor pollution, the detailed explanations above provide the paragraph locations and wording connections needed to review each question.
1. What is the Indoor Pollution IELTS Reading passage about?
The passage examines indoor air pollution and explains why pollution inside homes and buildings can sometimes be as concerning as outdoor pollution. It discusses household activities, water use, cooking, candles, poor ventilation and toxic chemicals as potential sources.
2. What are the main question types in Indoor Pollution Reading?
The passage contains Multiple Choice Questions for Questions 1–6 and Matching Features questions for Questions 7–13. These questions test your ability to understand main ideas, locate specific details, recognise paraphrases and identify cause-and-effect relationships.
3. Who are Richard Corsi and Cynthia Howard-Reed?
Richard Corsi and Cynthia Howard-Reed are environmental engineers whose research examined how household water-use activities can transfer chemicals from water into indoor air. Their study forms an important part of the passage.
4. Why are dishwashers mentioned in the passage?
Dishwashers are mentioned because their high-temperature water spray can transfer certain chemicals from water into the air. The passage uses this example to explain the process known as chemical stripping.
5. What does chemical stripping mean?
Chemical stripping refers to the removal or transfer of volatile chemicals from water into the air. The passage explains that factors such as chemical volatility, water temperature and surface area can affect this process.
6. Why is bottled water mentioned in the passage?
Bottled water is discussed because concerns about pollutants in tap water have encouraged many people to drink bottled water. However, the research suggests that some pollutants may still reach people through the air inside their homes.
7. How can I use Indoor Pollution Reading Answers with Location to review my mistakes?
Using Indoor Pollution Reading Answers with Location allows you to check not only whether your answer is correct but also where the supporting information appears in the passage. Look at the relevant paragraph and compare the keywords and paraphrased ideas with the question.
8. How can I solve Matching Features questions in this passage?
Start by identifying the main idea in each statement. Then scan the passage for related information rather than looking only for identical words. Pay attention to relationships such as inadequate ventilation → higher carbon dioxide levels and concern about tap water → increased bottled-water use.
9. Why is paraphrasing important in IELTS Reading Indoor Pollution Answers?
IELTS frequently expresses information in the questions using different words from the passage. For example, “designed for smaller numbers” refers to inadequate ventilation in an overcrowded classroom. Recognising such paraphrases can help you locate the correct information more quickly.
10. What should I focus on when reviewing the reading answers of Indoor Pollution?
When reviewing the reading answers of Indoor Pollution, focus on the evidence supporting each answer rather than memorising the answer itself. Check the relevant paragraph, identify the keywords, and note how the question paraphrases the information in the passage.
11. What vocabulary is useful for understanding the Indoor Pollution passage?
Important terms include chemical stripping, toxic chemicals, particulate matter, carbon monoxide, carbon dioxide, ventilation, water-borne pollutants and indoor air quality. Understanding these terms can make it easier to follow the scientific explanations in the passage.
12. How can I improve my performance using Indoor Pollution Reading Answers?
After completing the passage, use indoor pollution reading answers to analyse incorrect responses and identify why you chose them. Compare the question wording with the passage, mark useful paraphrases and review the location of supporting information.
13. How can this passage help with IELTS Reading preparation?
Practising indoor pollution reading answers can improve your ability to scan for details, understand scientific information, identify paraphrases and connect causes with their effects. These skills are useful across different IELTS Reading passages and question types.
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