Directions: Complete the following passage by using the words in the box. Each word can only be used once. Note that there is one word more than you need.

A. neighbouring；B. concerned；C. complete；D. earnest；E. fats F. maintenance；G. notably；H. operations；I. regularly；J. specifics；K. shift

A good grilling

As they reopen after lockdown, many restaurants are firing up their barbecues. Diners appreciate food grilled over glowing charcoal embers, but the 【小题1】 residents often do not. Pollution levels near restaurants can be 【小题2】 higher than average, because of emissions from kitchens. With the increasing popularity of indoor barbecuing, it is a problem that is set to get worse.

The researchers tested a commercial grill, 【小题3】 with the sort of multistage filtering system used in many — though by no means all — restaurants. Apart from typical pollutants and particulate matter, they also discovered polycyclic aromatic hydrocarbons (多环芳烃). These cancer-causing chemicals are mainly produced by the incomplete combustion (燃烧) of 【小题4】 and oil-based sauces. The researchers estimated that if their half-a-square-metre grill was used for nine hours a day, it would release between 400 and 500 kilograms of fine and ultrafine particulate matter into the air every year. With many restaurants using 2.5-square-metre grills 16 hours a day, the level of pollution from most commercial【小题5】 would be much higher.

The researchers are investigating which extraction systems best protect all the people 【小题6】 such as the restaurant employees. Taller chimneys are one option. But Dr Aleysa, an expert in combustion technology, suspects they would just 【小题7】 the pollution elsewhere. The results of these tests will be published next year.

Meanwhile, Dr Aleysa’s team have come up with their own solution: a new kind of grill, which they reckon can cut pollutants by 90%. Dr Aleysa is reluctant to go into 【小题8】. But the basic idea is that before being released to the outside, the fumes are sucked back down through the embers and into a combustion zone, where hydrocarbons and odour compounds are fully burnt. That lessens the need for expensive extraction systems and fiddly filters that must be 【小题9】 cleaned.

An industrial partner is keen to put the grill into production. It could go on sale by the middle of next year. It will cost a bit more than a standard grill, says Dr Aleysa. But he believes that would be offset by lower 【小题10】 costs. Better air quality around restaurants would be welcome. But the big test will be whether chefs believe the new grill can produce that same barbecue flavour.