1 a Read the title, the subtitle and the first paragraph of the text below. Then decide which answer (A or B) best describes the probable topic of the whole article.

A Dust in the home

B Dust in public buildings

b Read the first sentence or two of each paragraph. Decide which sets of paragraphs deal with each of these topics.

Fighting The Dust

We used to think that dust blew in through the window. Now we know better, says Alison Motluk

A It’s hard to defend yourself against dust. Attack it, and it scatters and escapes you, but the moment your guard is down it silently returns – on lampshades and bookshelves, in corners and under beds. And that’s just in your home. Imagine having to look after a larger place, somewhere packed with delicate objects, with tens of thousands of people passing through each year. So serious is the fight against dust that those responsible for running museums, art galleries and historic buildings have realised it can only be won by making it the subject of systematic research.

B Cleaning exhibits in museums and historic buildings takes a lot of time and money. But a more serious problem is that the process of removing dust can sometimes cause damage. Morten Ryhl­Svendsen of the National Museum of Denmark’s analytical lab in Copenhagen is studying dust deposition on 1000-year-old Viking ships on display at a museum in Roskilde. ‘Every time the ships are cleaned, some bits break off,’ he says. ‘Though some fragments can be retrieved from the vacuum cleaner bag and replaced, cleaning is clearly accelerating the exhibits’ decay. And no matter how small the breakage, each represents the disappearance of some information about the objects,’ Ryhl-Svendsen says.

C Several studies have been launched in the past few years, attempting to put the study of dust on a scientific footing. Researchers have been investigating where it comes from, and the best way of keeping it under control. ‘The conventional view is that dust comes from outside the building,’ says Peter Brimblecombe, an atmospheric chemist and dust expert at the University of East Anglia in Norwich, UK. He is involved in a study at London’s Tate Gallery which is beginning to overturn that idea. In the study, microscope slides were placed on top of the frames of several paintings and left there for seven days. Some were in older galleries, where ventilation was mainly through open doors and windows; others were in newer areas where the air within the room was continually recirculated by air conditioners. The amount of dust that had collected was measured and analysed, and it was found that the air-conditioned areas still had considerable amounts of dust.

D Ryhl-Svendsen and a colleague used a similar technique to study the dust on the Viking ships in They positioned sticky patches at various locations in and around the open ships. When they analysed the dust they had collected, they discovered a toxic plasticiser believed to come from floor tiles elsewhere in the museum, together with textile fibres, skin flakes and hair.

E Both studies indicated the same culprits: people like you and me visiting the exhibitions. Where there were large numbers, dust levels were high. And the objects that visitors got nearest to were the ones that were most densely shrouded in fluff. Skin flakes and strands of hair contribute to the problem, but the biggest menace turns out to be clothes. We are surrounded by an invisible cloud of fibres coming from the things we wear — woollen sweaters, coats, scarves and so on. In the case of the Viking ships, a noticeable proportion of the fibres were thin strands of blue denim from visitors’ jeans.

F So what is the answer? The electronics and pharmaceutical industries have already developed sophisticated devices such as air showers to clean anyone who sets foot inside their premises. They’re effective, but not exactly what a tourist might expect on a visit to a historical building.

G It turns out that much of the dust causing the problem is shed from our clothes between the shoulders and the waist. Dust licked up by feet is heavier and usually falls back to the ground. So clear plastic barriers up to shoulder level could cut out a good deal of the dustiness, say the researchers.

H They also discovered that the more vigorously people move, the more fibres their clothes shed, which suggests there might be some benefit in changing the way visitors are directed past exhibits. People tend to be most active at the beginning of their visit — adjusting rucksacks, taking off jackets and coats — so the most precious exhibits should be displayed last. This would have the added advantage, from a conservation point of view, that visitors will be getting tired by then and may spend less time admiring the exhibits. And no twists and turns, advises Brimblecombe: ‘Design routes so people don’t turn corners sharply or walk back and forth.’

I Brimblecombe has also found that for each additional metre people are kept back from furniture or pictures, the quantity of dust they deposit is halved. At least two metres should separate a piece of antique furniture, for example, from a visitor’s woollen jacket. It seems that the best way to protect museums and their contents for future generations to enjoy is to keep the current generation as far away as possible.

2 You have already done a sentence completion task with a bank of answers.
You may also have to complete sentences using a word or words from the text.

a Read through sentences 1-9 in the exam task, and underline key words. (The key words in sentences 1-3 have been underlined for you.) Use them to locate which part of the text each sentence relates to. Key words may be the same in the text and sentences (e.g. proper nouns) or they may be parallel expressions.

b When you complete the gaps in the sentences, make sure that:

• the word or words you write are exactly the same as in the text
• you keep within the word limit specified (usually between one and three words)
• your completed sentence makes sense and is grammatically correct.

Look at the completed question below, which relates to paragraph A of the text. What is wrong with this answer?

1 The authorities are aware that researchers is needed to solve the problem of dust in buildings containing historical items.