Outdoor, indoor, and human breath content measurements of ammonia by tunable diode laser spectroscopy technique

Abstract

Trace contents of ammonia in outdoor, indoor and exhaled air were measured on the base of high resolution absorption spectra. Tunable diode laser system developed for this purpose possesses approximately one second time constant, approximately 200 cm3 sample volume, 5 ppb sensitivity. The calibration of unit was based on measurements of relative intensities of sQ(3,1)...sQ(3,3) absorption lines of v<SUB>2s</SUB> and following calculation on the base of a priori data on strength and broadening coefficients of detected lines. Measured indoor contents of ammonia was in 5-10 times higher than outdoor contents. Approximately two times drop in NH<SUB>3</SUB> room content after 6 p.m. was detected. Obtained behavior of ammonia content in respiration right after the smoking demonstrates that the removing of ammonia from lungs has the ventilation character. Measured contents of NH<SUB>3</SUB> in human respiration was ranged between 120 and 220 ppb. The absence of ammonia content differences from respiration of smoking and non smoking persons demonstrates that the accumulation of NH<SUB>3</SUB> by human organism seems to be rather negligible for a short time exposure, e.g. like smoking.