Parameters determining the use of zeolite 5A as collector medium in passive flux samplers to estimate N 2 O emissions from livestock sources

Abstract

The present study analyzes the effect of parameters that determine the use of the zeolite 5A as collector medium in passive flux samplers (PFS) developed to estimate N₂O emissions from livestock buildings. The study analyzes the mass of N₂O collected on the zeolite 5A as a function of gas flow rate (40 and 130 ml/min), inlet mass of N₂O to the PFS (from 7 to 84 μg), adsorbent mass (4 and 13.6 g), length of the adsorbent bed (1.9 and 10.9 cm), and inlet N₂O concentration (0.6 and 2 ppmv). The mass of N₂O collected on the zeolite 5A ranged from 1.24 to 6.19 μg of N₂O/g of adsorbent, which was mainly affected by inlet N₂O concentration and mass of adsorbent contained in the PFS. The mass of N₂O collected presented a significant relationship with the inlet N₂O concentration and the adsorbent bed. Tests were performed using PFS in a laboratory farm under semi-real conditions. It was found that at sampling time of 1.5 h, the accuracy and precision of PFS was appropriate. Under evaluated conditions, a maximum variation between PFS and direct detection of around 12% was estimated.

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