China is going to host the Games of the XXIX Olympiad from 8-24 August 2008 in Beijing. The number of athletes and accompanying individuals expected to arrive at China for the Beijing Olympics is estimated at over 10 000 and among them at least 2 000 (20%) are suspected to suffer from respiratory allergies. It is important to monitor the pollen counts and improve air quality in Beijing because Olympic athletes would be exposed to airborne allergens and pollutants during competitions which could hinder peak performance. The main pollen and spore families in Beijing are Artemisia, Ambrosia, Chenopodiaceae and Gramineae. They can reach around 307 000 grains of pollen/1000 m(3) of air in August. Economic development in China is usually linked with worsening of air quality. Due to the adoption of various control measures, the ambient air quality in a number of areas in Beijing has actually improved. The ambient air TSP and SO(2) levels in Beijing have been decreasing in the last decade. However, ambient air NO(x) level has been increasing due to the increased number of motor vehicles. Nevertheless, dedicated medical facilities in Beijing will provide medical services to athletes and delegations from all over the world during the Beijing Olympic Games.