Residential indoor, outdoor, and workplace concentrations of carbonyl compounds: relationships with personal exposure concentrations and correlation with sources

Personal 48-hr exposures of 15 randomly selected participants as well as microenvironment concentrations in each participant's residence and workplace were measured for 16 carbonyl compounds during summer-fall 1997 as a part of the Air Pollution Exposure Distributions within Adult Urban Populations in Europe (EXPOLIS) study in Helsinki, Finland. When formaldehyde and acetaldehyde were excluded, geometric mean ambient air concentrations outside each participant's residence were less than 1 ppb for all target compounds. Geometric mean residential indoor concentrations of carbonyls were systematically higher than geometric mean personal exposures and indoor workplace concentrations. Additionally, residential indoor/outdoor ratios indicated substantial indoor sources for most target compounds. Carbonyls in residential indoor air correlated significantly, suggesting similar mechanisms of entry into indoor environments. Overall, this study demonstrated the important role of non-traffic-related emissions in the personal exposures of participants in Helsinki and that comprehensive apportionment of population risk to air toxics should include exposure concentrations derived from product emissions and chemical formation in indoor air.

Effects of different irrigation liquids and times on articular cartilage: an experimental, biomechanical study

To characterize the suitability of different solutions [6% Dextran, 5% sorbitol (I); 5% fructose (II); 5% mannitol (III); Ringer's solution (IV)] for arthroscopy, bovine knee articular cartilage specimens (n = 52) were immersed for 0, 2, 4, or 20 h before indentation creep testing, known as a sensitive probe for tissue degeneration. Immersion in liquid I for up to 20 h produced significant softening of articular cartilage [p < 0.05, Friedman two-way analysis of variance (ANOVA)]. Liquids II-III produced no statistically significant changes in the deformational characteristics of articular cartilage. After 2 h of immersion in liquid IV deformation increased and remained elevated over the observation period (p < 0.05, Friedman two-way ANOVA). Based on these results, the first and most remarkable softening of cartilage took place with Ringer's solution as compared with nonionic solutions. Therefore, the nonionic solutions, such as 5% fructose or mannitol, may have potential for use as an irrigation liquid during arthroscopic procedures.