SGP/PGS/C1 - Suspicious 2m data

KNF pump for 2m height (channel 1) started to leak on July 22, 2004 and sampled air was 
consequently "contaminated" by indoor air. The pump was replaced on August 19, 2005.

Either use another sampled height (4m, 25m, or 60m) or use data with caution.

• calculated concentration of CO2(co2ppm)
• 90% confidence limit of co2ppm(co2ppm_se)