Comparison of gravimetric PM data from the Harvard Impactors and Gent Stacked Unit PM 10 Samplers in Prague 2004 M. CIVIŠ 1, J. HOVORKA 1 and J. SCHWARZ 2 1 Institute for Environmental Studies, Charles University, Benátská 2, , Prague, Czech Republic 2 Institute of Chemical Process Fundamentals, Academy of Sciences of the Czech Republic, Rozvojová 2, , Prague, Czech Republic Motivation: Systematic sampling (every third day) and during four intensive seasonal campaigns (14 days per campaign) of aerosol fractions PM 10, PM 2.5, PM 1 using Harvard impactors (HI) and PM 10, PM 2.2 using Gent Stacked Unit PM 10 Samplers (SFU) on two locations in Prague within the year Evaluation of the both manual PMx sampling methods regarding to meteorology parameters. Comparison of HI method with SFU method on station 1 and comparison of SFU method on both stations. Station 2 (suburban) N 50º07.643´: E 014º23.064´ 285 m ASL Station 1 (urban) N 50º04.280´; E 014º25.253´ 225 m ASL Harvard Impactor – HI HI for PM 10 and PM 2.5 are single staged with flow rate 10 l/min while HI PM 1 has two stages and flow rate about 23 l/min. PM 10 was sampled on Quartz filters (37 mm, pore size μm). PM 2.5 and PM 1 fractions were caught on PTFE filters (37 mm, PE holding ring, pore size 2 μm) Gent Stacked Unit PM 10 - SFU At the inlet of SFU sampler are single staged, PM 10 impactor with flow rate 16 l/min. Then aerosol passes through filter cassette, consisting in-serial two PTFE Nuclepore® filters. Pore size of the first filter is 8 μm. Pore size of the second filter is 0.4 μm. Coarse of particles from μm is collected on the first filter, particles smaller than 2.2 μm are collected on the second filter The study was conducted within the project „Comprehensive size resolved characterization of atmospheric particulate matter in Prague“ supported by GACR grant No. 205/03/1560 Station 1Station 2 PM 10 PM 2,5 PM 1 SFU 10 SFU 2,2 SFU 10 SFU 2,2 St. 1 PM /0.22 PM /0.2280/0.22 PM /0.2280/0.22 SFU /0.2373/0.2368/0.2552/0.27 SFU /0.2757/ /0.27 St. 2 SFU /0.2280/ / /0.22 SFU /0.2280/ / /0.22 Observed time period Method and location Regression equation Correlation coefficient, number of pairs/critical values Spring campaign PM 10 St.1y=0.02x (14/0.48) Summer campaign PM 2.5 St. 1y=0.09x (15/0.48) PM 1 St. 1y=0.07x (15/0.48) SFU 10 St. 2y=0.09x (13/0.51) Autumn campaign PM 2.5 St. 1y=0.11x (15/0.48) PM 1 St. 1y=0.12x (15/0.48) SFU 10 St. 2y=0.08x (14/0.5) Year 2004SFU 2.2 St.1y=-0.04x (58/0.27) SFU 2.2 St. 2y=-0.02x (95/0.21) PM 10 St. 1y=-0.02x (89/0.22) Observed time period Method and location Regression equation Correlation coefficient, number of pairs/ critical values Winter campaign PM 2.5 St. 1y=-0.21x (12/0.53) Spring campaign PM 2.5 St. 1y=-0.09x (15/0.48) SFU 2.2 St. 2y=-0.53x (15/048) Year 2004SFU 10 St. 1y=-0.13x (74/0.23) SFU 10 St. 2y=-0.11x (94/0.21) HI coarse St. 1y=-5.79x (89/0.22) SFU coarse St. 1y=-2.17x (76/0.23) Pearsont Correlation of the methods Relations between PM and average day temperature Relations between PM and average day wind speed Conclusion: Sampling with HI method measured (  =0.05) higher concentrations of PM 10 and PM 2.5 than SFU PM 10 and PM 2.2 on both stations. Results show that air masses are better mixed in Prague for PM 2.5 which does not apply for PM 10. SFU 2.2 on both stations correlated well with average day temperature during the whole year SFU 10 on both stations correlated with average day wind speed during the whole year Correlation of aerosol fractions with relative humidity was not found. Negative correlations between coarse fractions and average wind speed measured by both methods on station 1 was observed. Highest concentrations of HI coarse occurred with wind blowing 2-3 m/s. Highest SFU coarse concentrations occurred with wind speed 1-2 m/s. N