Cleaners, farmers and hairdressers are more likely to suffer from asthma than other workers because of their jobs, scientists suggest.
They found the workplace could be to blame for around one in six cases of the condition among adults.
Those regularly exposed to cleaning or disinfectant products, flour, metal and metal fumes were most at risk of developing asthma, they said.
The authors examined the records of around 7,500 British adults whose health was tracked from birth in 1958.
Information relating to the symptoms of asthma or wheezy bronchitis was collected at the ages of seven, 11, 16, 33 and 42.
The workplace could be to blame for around one in six cases of adult asthma
The group - which excluded people who reported these symptoms before the age of 16 - was tested for sensitivity to allergens. Scientists also examined their lung power between the ages of 42 and 45 and questioned participants on their work history.
Their analysis showed the start of asthma in adulthood was clearly linked to 18 types of job, including farming, which more than quadrupled the risk of developing the condition, and hairdressing, which almost doubled the risk.
Those who worked in printing were three times more likely to contract the condition than their peers, while cleaners were up to twice as likely to develop breathing problems, the scientists concluded.
Meanwhile, those exposed to high risk agents - flour, enzymes, cleaning or disinfectant products, metal and metal fumes, and textile production - were 53% more likely to suffer from asthma.
Ask if they have their reliever inhaler (usually blue) and where it is. You may need to get it out of their bag for them.
Encourage them to take one to two puffs of their reliever inhaler.
Make sure they are sitting up.
Encourage them to take slow and steady breaths.
Keep them calm and reassure them.
If they are still not feeling better after two minutes they can take two puffs of their reliever again and continue to do so every two minutes (up to a maximum of 10 puffs).
If they feel better, they should be OK to carry on with their day - but make sure they see a doctor as soon as possible (ideally the same day).
If at any time you are worried about them, call an ambulance.
If after 10 minutes they don't feel better and their inhaler doesn't seem to be helping them, then call an ambulance.
If the ambulance hasn't arrived after 10 minutes then the sufferer should repeat Step 6, until help arrives.
The authors said: "We have shown that occupations and exposures related to cleaning and other irritant exposures are consistently associated with an increased risk of adult-onset asthma and that, overall, occupational exposure accounts for an estimated 16% of disease.
"The findings of this study are the first of their kind in the UK and provide valuable information for those concerned with reducing the incidence of asthma in adult life."
Cleaning products have previously been identified as a potential cause of asthma.
The scientists, led by Rebecca Ghosh, of Imperial College London, said: "We observed consistently higher risks associated with working as a cleaner, in jobs likely to include cleaning tasks, and in jobs likely to lead to exposure to cleaning and disinfecting products."
But they said the scale of the problem caused by such products in the UK remains unclear.
Jon Ayres, professor of environmental and respiratory medicine at the University of Birmingham, welcomed the study's "robust" findings.
He said: "We already know that occupational asthma costs many millions of pounds to the UK economy each year.
"This latest research has identified cleaners as a new and very important at-risk group. However, we already know how to prevent occupational asthma and how to solve it.
"The difficulty is the expense for small and medium enterprises which may save just one case of adult-onset asthma over a long period.
"The main message from this study is that employers need to pay greater attention to exposures in at-risk groups. Both Government and industry need to reconsider how they can best control exposure and reduce adult-onset asthma due to occupation."
Somnath Mukhopadhyay, a paediatrics expert at Brighton and Sussex Medical School, said the "remarkable" study would send important messages to asthma sufferers and doctors.
Prof Mukhopadhyay added: "It shows that a high proportion of adult asthma in the UK could result from occupational exposure.
"It throws light on a range of new occupations that may represent significant risk factors for asthma. The study should thus influence routine history-taking in day-to-day general practice in the UK, as identifying the precipitant for asthma is a key step in asthma management.
"It also raises interesting questions for the future. For example, does the removal of these factors at the time of initial presentation to primary care prevent the progression of the disease?"
The study was published in the respiratory journal Thorax.
The groups of workers deemed to be at particular risk of developing asthma include: cooks, waiters and bartenders, personal care workers, hairdressers and beauticians, animal producers, aircraft engine mechanics, typesetters, sewing machine operators, cleaners, domestic helpers, messengers and porters, doorkeepers and watchmen, and construction and manufacturing labourers.