The investigation of atmospheric particulate matter pollution in Suzhou

Objective To investigate the pollution status,vertical distribution and concentration variation within 24 hours of total suspended particles(TSPs),particulate matter ≤10 μm(PM10),particulate matter ≤ 5(PM5)and particulate matter ≤ 2.5 μm(PM2.5) in major functional areas of Suzhou and the protective effect of different type masks on particulate matter.Methods(1) The concentration of atmospheric TSPs,PM10,PM5 and PM2.5 in seven functional areas in Suzhou was monitored for three consecutive days.(2) A residential building of 25 stories was chosen and the concentration of TSPs,PM10,PM5,PM2.5 was detected at the 1st,5th,10th,15th,20th and the 25th floor respectively.(3) The concentrations of the four particulate matter were detected every two-hours for three consecutive days to investigate how concentration of particulate matter varies within 24 hours.(4) The concentration of the four kinds of particulate matter was analyzed with the sampling head of monitor wrapped with disposable non-woven medical mask,fashion-type mask,gauze mask or activated carbon anti-dust mask respectively,and the protective effect of the four masks on particulate matter was compared.Results(1) The concentration of PM2.5 was higher than the national health limit in all seven functional areas in Suzhou.(2) No significant difference in vertical distribution of particulate matter was found among different floors in residential buildings(P0.05).(3) Two small peaks of particulate matter appeared in the morning and evening respectively while the top appeared at dawn(P0.05).(4) Disposable non-woven medical mask showed the best protective effect on particulate matter among the four tested masks.Conclusion PM2.5 is the main particulate matter in Suzhou area.In addition the 4 kinds of particulate matter: TSP,PM10,PM5 and PM2.5 are of higher concentration in the early morning.No significant difference was detected from an altitude of less than 75 meters.Disposable non-woven medical masks is suggested to be used for defending people from particulate matter in daily life.