Winter weather can be a major trigger for asthma, a chronic inflammatory disease of the airways, due to increased indoor activity, respiratory infections and breathing cold air.

This year, asthma patients have another winter problem: smog arising from a seasonal increase in coal use in China. Fine dust levels have surged to several times the usual concentrations, according to a state-run environment research center.

“Patients suffering from asthma should be extra vigilant about the increase in the level of fine dust in the air because it could aggravate asthma symptoms,” said Yoo Se-hwa, a leading respiratory physician who serves as a member of the medical assessment committee at the Health Insurance Review and Assessment Service.

“We don’t have documents as of now to scientifically demonstrate the relationship between the level of fine dust and asthma. But the probability of the air pollution worsening asthma symptoms is very high,” he said.

Asthma is a chronic disease that causes airways to swell and narrow. Asthma patients repeatedly and convulsively suffer from wheezing, shortness of breath, chest tightness and coughing. The disease symptoms can be triggered by breathing in allergens such as pet hair, dust mites, pollen and chemical substances in the air and food.

The disease is caused by both environmental and genetic factors, and can be worsened by changes in weather, flu, air pollution, smoking, exercise and stress.

According to a study released by HIRA on Thursday, the number of asthma patients visiting hospitals has peaked in December and April in the last five years.

In the study on asthma patients between 2008 and 2012, the number of people treated for asthma symptoms averaged 455,858 in April, and 445,830 in December, about 60 percent higher than patient numbers in the summer months.

“In Spring, asthma symptoms get worse due to pollen and yellow dust. But in the winter, being indoors can cause problems because of poor air quality as well as dryness,” Yoo said.

More than 2.33 million Koreans are affected by asthma, the state-run insurance assessment agency said.

The disease can be managed with the use of drugs, but can be dangerous for kids because their airways are very sensitive and not fully developed. Children under 10 account for 36.4 percent of overall asthma patients in Korea, HIRA added.

Parents of asthmatic children need to learn about the disease and be ready for it. If not properly treated, a sudden asthma attack could threaten a child’s life, Yoo said. Having difficulty breathing can be also very frightening experience for children, he added.

In the winter time, patients are advised to visit asthma clinics regularly to check the condition of their lungs and take preemptive medication, particularly before going outside in cold weather.

“Wear masks that could filter air pollutants or wear a scarf over your nose and mouth in order to warm up the air before you breathe it in,” Yoo suggested.

It is also important to keep one’s home as asthma-friendly as possible, others say, through vacuuming, using anti-allergy bedding and using air filters.

By Cho Chung-un (christory@heraldcorp.com)