For the first time since 1997, the Chinese capital enjoyed a spring without sandstorms, allowing people to dispense with facemasks were it not for the flu-like epidemic.

Li Huang, vice-director of the State Meteorological Administration, said: "The weather conditions -- sandstorm-free in spring -- in Beijing were also good for fighting SARS."

Other areas in northern China also recorded their lowest number of dusty days in five years, Li said in Beijing on Friday.

China recorded only seven periods of dusty weather in 2003 in the peak March to May sandstorm season, compared to the average of 13, in the past four years, the meteorological agency statistics revealed.

Li said Beijing had escaped dusty conditions this year partly because of increased rainfall and the afforestation of Beijing suburbs.

He said there is no scientific evidence linking sandstorms to SARS. But healthcare professionals believe that pollutants caused by sandstorms -- grit, dust and sand -- would have worsened the SARS outbreak.

They said that a sandstorm-free spring was a blessing for a city cursed by the unprecedented disease.

Yan Weizhong, a lung disease expert with Beijing Hospital, said drifting sand and dust during sandstorms can trigger respiratory ailments.

"The high density of small powdery particles brought by sandstorms are most likely to ... cause people to cough and contract asthma, fuelling outbreaks of infectious disease," Yan said.

On average, Beijing has 5.8 days of dusty weather in a year. But the city saw 10 periods of dusty weather each year from February 2000, said Guo Hu, director of the Beijing Meteorological Station.

Li said that strong winds tend to pick up sand from desert regions in northwestern China and the Inner Mongolia Autonomous Region, turning into sandstorms as they travel.

But cold air currents blowing across north China were weaker this spring and did not last as long as in previous years, reducing the risk of sandstorms, he said.

Only two sandstorms struck northern China this spring, between April 8 and 17, when strong winds carrying sand reduced visibility to less than a kilometer, according to the meteorological agency.

Li said that China has closely co-operated with South Korea and Japan in sharing information about sandstorms and strengthening monitoring of the natural phenomena.

(China Daily June 7, 2003)