A shroud of fine dust hangs over the port city of Kaohsiung in southern Taiwan Monday after a massive sandstorm from North China arrived overnight, concentrating suspended particles at "hazardous" levels in some areas. Central News Agency

The public does not have to worry about the impact of sandstorms from the mainland on air quality, as Taiwan is less vulnerable to sandstorms than Japan and South Korea - as upper-level air moves mostly westward, meteorologists said Monday.

The largest sandstorm from North China to ever hit Taiwan struck Sunday, shrouding the island in a white haze and bringing particulate concentrations in the air to "hazardous" levels of more than 1,000 micrograms per cubic meter an hour, compared with normal levels of less than 150 micrograms per cubic meter per hour.

Lin Pay-liam, chairman of the Department of Atmospheric Sciences at National Central University, said that drought and wind contribute to the emergence of duststorms and that sandstorms from the mainland rarely affect Taiwan, but that the weekend's storm was strengthened by a cold front.

Echoing Lin's comments, Gloria Kuang-jung Hsu, a professor at National Taiwan University's Department of Atmospheric Sciences, said that because Taiwan is located at the periphery of areas that can be affected by sandstorms from the mainland, it is influenced only occasionally.

Although some areas experienced extremely high concentrations of suspended particles Sunday, the levels of pollution that Taiwan saw were not as severe as those in many other regions, where people have to cover their heads and faces when a duststorm hits, Hsu said.

She said the public should pay more attention to wind-borne dust problems in the middle and downstream sections of Tachia River in the central county of Taichung, which are more likely to have a negative impact on air quality in Taiwan than sandstorms from the mainland.

As to whether the frequency of sandstorms from the north affecting Taiwan will increase, both experts said further observation would be required.

The impact of the sandstorm on air quality in northern Taiwan decreased Monday as it moved into central and southern Taiwan.

The Environmental Protection Administration warned that people in central and southern Taiwan should protect themselves as air quality in the areas could become a threat. The pollutant standards index (PSI) values recorded by three monitoring stations in the southern Pingtung County neared 400 Monday morning. A PSI value greater than 100 means that at least one "criterion pollutant" (a pollutant monitored as a pollution component) has reached a level that could affect the health of people in sensitive groups.

The county government has issued an order to factories under its jurisdiction to reduce production in order to cut air pollution.

Severe pollution has caused the number of medical clinic visits by residents in the county to rise significantly, according to the county government.

An observation station in Tainan County recorded 1,230 micrograms of dust per cubic meter at 10 pm Sunday, but the number dropped to 849 micrograms per cubic meter by 11 am Monday, according to the county government.

Kaohsiung City and the outlying Matsu and Kinmen islands also suffered from high particle pollution, with levels of more than 1,000 micrograms per cubic meter per hour recorded in some areas early Monday.

China Daily/CNA

(HK Edition 03/23/2010 page4)