Development of a new semi-volatile organic compound sampler

Conference · Sat Dec 31 04:00:00 EST 1994

OSTI ID:197390

Sioutas, C; Koutrakis, P ^[1]; Burton, R M ^[2]

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1. Harvard Univ., Boston, MA (United States). School of Public Health
2. Environmental Protection Agency, Research Triangle Park, NC (United States)

A new sampler has been developed to sample semi-volatile organic compounds. The sampler utilizes the principle of virtual impactor to efficiently separate the particulate from the gas phases of organic compounds. The virtual impactor consists of a slit-shaped nozzle where the aerosol is accelerated, and another slit-shaped nozzle that collects the particulate phase of organics (plus a small and known fraction of the gas phase). The acceleration slit is 0.023 cm wide, the collection slit is 0.035 cm wide, and both slits are 11 cm long. The virtual impactor`s 50% cutpoint has been determined experimentally to be 0.12 {micro}m. In addition, interstage losses have been determined (in all configurations tested, particle losses ranged from 5--15%). The impactor`s sampling flow rate is 284 liters/minute, with a corresponding pressure drop of 100 inches H{sub 2}O. Higher or lower sampling flow rates can be achieved by increasing or decreasing the length of the slits. Tests for volatilization losses have been conducted by generating organic aerosols of known volatility, and comparing the impactor`s collection to that of a filter pack sampling in parallel. The experiments demonstrated negligible volatilization losses (< 5%) for the compounds tried. Particles are collected on a filter connected to the minor flow of the impactor, followed by a sorbent bed to collect material that volatilized from the particles. The organic gas phases is collected on a sorbent bed, connected to the major flow of the impactor.

• OSTI ID: 197390
• Report Number(s): CONF-9405167--
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
AIR POLLUTION MONITORING
AIR SAMPLERS
DESIGN
ORGANIC COMPOUNDS
VOLATILE MATTER