The Influences of Airflow on the Concentrations of PM_(10),PM_(2.5) and PM_(1.0) in Urumqi,Xinjiang,China

With a cluster analysis on the 72 h back trajectories of the daily ariflow and the observed data of PM10,PM2.5 and PM1.0 in Urumqi city in each season during 2009-2010,we explored the effects of the airflows on the concentrations of the three PMs.The results showed that: In winter,the air pollutent could be carried away or diffused by the airflow,the mass concentration of the particle aerosols with different size had a negative correlation with the airflow speeds.In spring,the airflows passing through the desert areas could carry dust aerosols to the study city,making the particle spectrum distribution move to the corse fraction.In summer,the atmosphere was clean,the NW airflows,which carried urban aerosols,had great influences on the background concentration,while the airflow from the other directions,which didn't carry extra-sourced contamination,basicly had a negative correlation with the aerosol concentrations.In autumn,the extra-sourced contamination didn't had great influences on the city,and the air flows were not so strong,so there were no significant differences between the concentrations of the three PMs.