As winter approaches, public concern about the toxic smog blowing in from China is growing. The smog in China gets worse during the winter as people burn coal for heating.

The smog contains a high level of “particulate matter,” which refers to extremely small pollutant particles floating around in the air. These particles include nitric and sulfuric acids, organic chemicals and metals. Their density is diluted as they cross the West Sea, but meteorologists say up to 50 percent of them reach Korea.

These particles pose serious health hazards as they are not filtered out by the nose and throat due to their small size. They are grouped into two categories: PM10 and PM2.5. PM10 stands for particulate matter up to 10 micrometers in size, while PM2.5 refers to fine particles smaller than 2.5 micrometers.

PM10 particles pose a health concern because they can be inhaled into and settle in the bronchi and lungs. PM2.5 is even more hazardous as particles of this size can penetrate the deepest part of the lungs and may even get into the bloodstream.

Scientific studies link particle pollution exposure to a variety of health problems, including premature death of people with heart or lung diseases, nonfatal heart attacks, aggravated asthma and decreased lung function.

As public concern about particle pollution grows, the government has started to provide forecasts of levels of particulate matter in the air, just like weather forecasts, to help people avoid exposure to elevated levels of this pollution.

Yet the trial service is very limited in terms of coverage and accuracy. Currently it only covers the capital area and the information it offers is not detailed. The Ministry of Environment plans to launch full-fledged service next February.

Even then, however, the service would only provide forecasts of PM10 particles. Due to the lack of measuring equipment, forecasts of more hazardous PM2.5 particles are scheduled to start from 2015.

Even if measuring equipment is available, it would still be difficult to offer accurate forecasts unless China provides Korea with data about the origin of the smog and its composition.

Although China has started a campaign to reduce air pollution, its smog problem is forecast to continue for at least five years. Under these circumstances, the least China could do to help its neighbors mitigate damage from the smog is to share its data with them. Yet China is reluctant to give Korea access to its smog data.

The Korean government needs to pressure Beijing to disclose its data, while accelerating efforts to provide more detailed and accurate pollution forecasts, including those of PM2.5 particles.