Atmospheric Peroxy Radical Measurement Method By Chemical Amplification And Its Application In Chemical Kinetics

peroxy radical measurement by chemical amplification (PERCA) is one important method of detecting atmospheric RO_x. PERCA can real-time, on-line, contimuously determine the atmospheric free radical, also volume small, the movement cost is low, is widely applied in the atmospheric chemistry research.This article has set up the Shaaxi normal university (SNNU) peroxy radical measurement system SNNU-PERCA and its calibration system, optimized the CO-NO-HO₂ chemistry amplifying system determination condition, the CO best density is 9.3%, the NO best density is 3.3 ppmv, compared the glass amplifier after the experiment to surpass the Teflon tube amplifier, the experiment has determined the free radical wall reaction rate constant, and carried on the adjustment with chemistry box model computation result, the experiment obtained this method essential parameter chain length (CL=152±11 (σ)). The SNNU-PERCA detection limits is 1-2 pptv (10 min determination), response time is smaller than 1 s, resolving power 30 s, 5 parallel determine 10 pptv the HO₂ result the relatively standard deviation to be smaller than 5%. The HO₂ density in 200 pptv scope, the free radical signal and the density assume the linear relations. The main gas components of the atmosphere do not remarkabley disturb the measurement. The experiment obtains the chain length reliability and chemistry box model computation result carried on the contrast, the result has been consistent.From the experiment discovered for the first time the dimethyl ether may substitute CO to take the chain-carrying agent of the peroxy free radical chemistry amplifier system, and optimized the CH₃OCH₃-NO-HO₂ chemistry amplifying system determination condition, the CH₃OCH₃ best density is 1.876 ppmv, the NO best density is 1.3ppmv, and obtained this method chain length CL=124, 5 parallel determinations densities of HO₂ are the 44.0pptv, the relatively standard deviation is smaller than 4%; Although chemistry box model computed result indicated the dimethyl ether, the ethene, the propene and the ethanol all can take the chain-carrying agent of the peroxy free radical chemistry amplifier system, and their simulation chain length all grows up compared to the CO-NO-HO₂ chemistry amplifying system's, but experiments proved the ethene, the propene and the ethanol have not suit the chain-carrying agents.Used the PERCA method union tubular mobile technology basically to determine the free radical production of the ozone ethene reaction, the result has been consistent with the literature value.Used the PERCA method to carry on the determination to March campus environment atmosphere, had discovered the peroxy free radical signal had the obvious daily variation, the HO₂ free radical strongest about 14:00 appeared a peak value in the sunlight. The experiment obtains the noon peroxy free radical density approximately 11 pptv, the observation had discovered the free radical the density has the direct ratio with the ozonedensity but to have the inverse ratio with the nitrogen dioxide density.