Air quality index, mercury drop

Two pigeons huddle on the ground in the rain outside the National Taiwan Democracy Memorial Hall yesterday. PHOTO: GEORGE TSORNG, TAIPEI TIMES

The weather is expected to turn cooler today and tomorrow as a cold mass from the north moves across the nation, the Central Weather Bureau said yesterday.

The bureau further cautioned that the temperature is likely to drop to 13oC in the north and northeast Taiwan, 15oC in the middle and the east of Taiwan, and 16oC in southeast Taiwan.

The cold mass is expected to weaken by Wednesday, the bureau said.

The bureau also issued a strong wind alert to residents of coastal areas and Hengchun (恆春) because of a strong seasonal wind from the northeast. The wind is expected to generate gusts reaching between 76kph and 102kph.

Meanwhile, the air quality index in western Taiwan continued to fall into the "substandard" category with floating particulate matter (PM) permeating the air, the Environmental Protection Administration (EPA) said yesterday.

The present Pollutant Standards lndex (PSI) is between 110 and 130, which indicates that the air quality is harmful to human health.

PSI is calculated by the density of pollutants in the air, including PM10 (particulate matter between 2.5 to 10 micrometers in diameter), sulfur dioxide, carbon monoxide, nitrogen dioxide and ozone.

A PSI of 0 to 50 is good, 51 to 100 is moderate, 101 to 199 is unhealthy, 200 to 299 is very unhealthy and above 300 is hazardous.

The administration urged citizens to wear face masks when going outdoors in the next few days, particularly those with allergies and heart or respiratory conditions.