Measurement of overall uptake coefficients for HO2 radicals by aerosol particles sampled from ambient air at Mts. Tai and Mang (China)

摘要

HO uptake coefficients for ambient aerosol particles, collected onquartz fiber filter using a high-volume air sampler in China, were measuredusing an aerosol flow tube coupled with a chemical conversion/laser-inducedfluorescence technique at 760 Torr and 298 K, with a relative humidity of75%. Aerosol particles were regenerated with an atomizer using the waterextracts from the aerosol particles. Over 10 samples, the measured HOuptake coefficients for the aerosol particles at the Mt. Tai site were rangedfrom 0.13 to 0.34, while those at the Mt. Mang site were in the range of0.09–0.40. These values are generally larger than those previously reportedfor single-component particles, suggesting that reactions with the minorcomponents such as metal ions and organics in the particle could contributeto the HO uptake. A box model calculation suggested that theheterogeneous loss of HO by ambient particles could significantlyaffect atmospheric HO concentrations and chemistry.