Asthma Northern Ireland highlights fatal attack risks
Asthma UK has said about 40% of people with the condition in Northern Ireland are underestimating their risk of having a potentially fatal attack.
Every year more than 20 people in Northern Ireland die from asthma.
More than 1,700 people are hospitalised.
The charity said asthma attacks and hospital admissions could be prevented if people took their medication and had regular consultations with the GP or asthma nurse.
Speaking on World Asthma Day, sufferer Steven-James Stothers, 23, said there was not enough awareness of the risks associated with the condition.
"During my late teenage years I rebelled against taking my medication because I wanted to fit in with my friends," he said.
"Throughout that time I was in hospital at least once a month after having an attack but then I realised I needed my inhalers to keep healthy.
"I'd encourage everyone with asthma to avoid attacks because having one is one of the most frightening experiences you can have."
Asthma UK Northern Ireland said people with asthma could find out their risk of having an attack by taking the Triple A Test .
It asks simple questions about factors which have all been linked to an increased or highly increased risk of an asthma attack.
Joan O'Hagan, director of Asthma UK Northern Ireland, said: "It's extremely worrying that many people with asthma in Northern Ireland do not realise their own risk of ending up in hospital.
"As up to 75% of emergency hospital admissions are preventable with better management and support, it's vitally important that the 182,000 people with asthma in Northern Ireland understand their condition and it is crucial that they are supported by healthcare professionals who can help them to reduce their risk."