A recirculating equilibrium still was used to measure pressure-temperature-liquid composition-vapor composition (PTxy) data on 18 dilute mixtures of water(1) + glutaraldehyde(2) between 38 degrees and 85 degrees C. The Henry＇s constants, H-2,H-1 (kPa/mole fraction), derived from the PTxy data, were fitted by least-squares to give the equation, In H-2,H-1 = 29.1352 -9187.99/T(K). To facilitate calculation of glutaraldehyde exposure during typical use, the Henry＇s constant correlation was used to compute concentrations of glutaraldehyde in air saturated by aqueous glutaraldehyde solutions. Vapor-pressure data for a dried sample of pure glutaraldehyde were measured in an ebulliometer between 55 degrees and 163 degrees C. An Antoine equation fitted to the intermediate temperature data between 74 degrees and 109 degrees C gives a normal boiling point for glutaraldehyde of 189.4 degrees C and a 20 degrees C vapor pressure of 0.044 kPa. The log vapor pressure vs. 1/T(K) curve shows downward curvature at both the high-temperature and low-temperature ends. This suggests (i) a strong hydrogen-bonding effect at low temperatures and (ii) the possibility of polymerization of the sample at high temperatures. Finally, PTx data were measured in an ebulliometer for four aqueous mixtures between 10 and 50 mass % glutaraldehyde. Henry＇s constants derived from infinite-dilution activity coefficients from a Barker＇s method fit to the PTx data agree with the Henry＇s constants from the PTxy data. (C) 1998 Elsevier Science B.V. All rights reserved.