C.K. Wilkins

Acute airway effects of formaldehyde and ozone in BALB/c mice

1 Concentration and time-effect relationships of formaldehyde and ozone on the airways were investigated in BALB/c mice. The effects were obtained by continuous monitoring of the respiratory rate, tidal volume, expiratory flow rate, time of inspiration, time of expiration, and respiratory patterns. 2 With concentrations up to 4 p.p.m., formaldehyde showed mainly sensory irritation effects of the upper airways that decrease the respiratory rate from a trigeminal reflex. The no-effect level (NOEL) was about 0.3 p.p.m. This value is close to the human NOEL, which is about 0.08 p.p.m. 3 Ozone caused rapid, shallow breathing in BALB/c mice. Later on, the respiratory rate decreased due to another vagal response that indicated an incipient lung oedema. The NOEL in mice was about p.p.m. during 30 min of ozone exposure. No major effect occurs in resting humans at about 0.4 p.p.m. 4 Thus, the upper airway irritant, formaldehyde, and the deep lung irritant, ozone, showed the same types of respiratory effects in humans and in BALB/c mice. Also, the sensitivity was nearly identical. Continuous monitoring of respiratory effects in BALB/c mice, therefore, may be a valuable method for the study of effects of other environmental pollutants, which, however, should be confirmed in further studies.

Effects of R-(+)-and S-(-)-limonene on the respiratory tract in mice

The effects of airborne R-(+)- and S-(-)-limonene were studied in conscious BALB/c mice by continuous monitoring respiratory rate (f), tidal volume (VT) and mid-expiratory flow rate (VD) during an exposure period of 30 min. Both enantiomers decreasedffrom a trigeminal reflex, i.e., due to sensory irritation. The exposure concentration decreasingf by 50% (RD50) in the first 10 min of the exposure period was estimated to be 1076 ppm for R-(+)-limonene and 1467 ppmforS-(-)-limonene. Resultsforsensoryirritation ofR –(+)-limonene in BALB/c mice and humans are in close agreement. The reported sensory irritation threshold is above 80 ppm in humans while the no – observed – effect level was estimated to be 100 ppm in mice. The enantiomers were devoid of pulmonary irritation or general anesthetic effects with R-(+)-limonene <1599 ppm and S-(-)-limonene <2421 ppm. R-(+)-limonene did not influence VT below 629 ppm. S-(-)-limonene increased VT above 1900 ppm. Both enantiomers induced a mild bronchoconstrictive effect above 1000 ppm.

Use of thermal desorption gas chromatography-olfactometry/mass spectrometry for the comparison of identified and unidentified odor active compounds emitted from building products containing linseed oil

The emission of odor active volatile organic compounds (VOCs) from a floor oil based on linseed oil, the linseed oil itself and a low-odor linseed oil was investigated by thermal desorption gas chromatography combined with olfactometry and mass spectrometry (TD-GC-O/MS). The oils were applied to filters and conditioned in the micro emission cell, FLEC, for 1-3days at ambient temperature, an air exchange rate of 26.9h(-1) and a 30% relative humidity. These conditions resulted in dynamic headspace concentrations and composition of the odor active VOCs that may be similar to real indoor setting. Emission samples for TD-GC-O/MS analysis from the FLEC were on Tenax TA. Although many volatile VOCs were detected by MS, only the odor active VOCs are reported here. In total, 142 odor active VOCs were detected in the emissions from the oils. About 50 of the odor active VOCs were identified or tentatively identified by GC-MS. While 92 VOCs were detected from the oil used in the floor oil, only 13 were detected in the low-odor linseed oil. The major odor active VOCs were aldehydes and carboxylic acids. Spearmen rank correlation of the GC-O profiles showed that the odor profile of the linseed oil likely influenced the odor profile of the floor oil based on this linseed oil.