Evaluation of offline sampling for atmospheric C3-C11 non-methane hydrocarbons.
J Environ Sci (China)
; 113: 132-140, 2022 Mar.
Article
em En
| MEDLINE
| ID: mdl-34963523
ABSTRACT
The concentration variation of C3-C11 non-methane hydrocarbons (NMHCs) collected in several types of commercial flexible bags and adsorption tubes was systematically investigated using a gas chromatography-flame ionization detector (GC-FID) system. The percentage loss of each NMHC in the polyvinyl fluoride (PVF) bags was less than 5% during a 7-hr storage period; significant NMHCs loss was detected in aluminum foil composite film and fluorinated ethylene propylene bags. The thermal desorption efficiency of NMHCs for adsorption tubes filled Carbopack B and Carboxen1000 sorbents was greater than 95% at 300â, and the loss of NMHCs in the adsorption tubes during 20-days storage at 4â was less than 8%. The thermal desorption efficiency for C11 NMHCs in the adsorption tube filled with Carbograph 1 and Carbosieve Sâ
¢ absorbents was less than 40% at 300â, and pyrolysis of the absorbents at 330â interfered significantly with the measurements of some alkenes. The loss of alkenes was significant when NMHCs were sampled by cryo-enrichment at -90â in the presence of O3 for the online NMHC measurements, and negligible for enrichment using adsorption tubes at 25â. Although O3 scrubbers have been widely used to eliminate the influence of O3 on NMHC measurements, the loss of NMHCs with carbon numbers greater than 8 was more than 10%. Therefore, PVF bags and adsorption tubes filled Carbopack B and Carboxen1000 sorbents were recommended for the sampling of atmospheric NMHCs.
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Base de dados:
MEDLINE
Assunto principal:
Poluentes Atmosféricos
/
Metano
Idioma:
En
Revista:
J Environ Sci (China)
Assunto da revista:
SAUDE AMBIENTAL
Ano de publicação:
2022
Tipo de documento:
Article
País de afiliação:
China