Volatile organic compound concentrations and emission rates in new manufactured and site-built houses

Concentrations of 54 volatile organic compounds (VOCs) and ventilation rates were measured in four new manufactured houses over 2-9.5 months following installation and in seven new site-built houses 1-2 months after completion. The houses were in four projects located in hot-humid and mixed-humid climates. They were finished and operational, but unoccupied. Ventilation rates ranged from 0.14-0.78 h-1. Several of the site-built houses had ventilation rates below the ASHRAE recommended value. In both manufactured and site-built houses, the predominant airborne compounds were alpha-pinene, formaldehyde, hexanal, and acetic acid. Formaldehyde concentrations were below or near 50 ppb with a geometric mean value for all houses of 40 ppb. Similarities in the types of VOCs and in VOC concentrations indicated that indoor air quality in the houses was impacted by the same or similar sources. Major identified sources included plywood flooring, latex paint and sheet vinyl flooring. One site-built house was operated at ventilation rates of 0.14 and 0.32 h-1. VOC emission rates calculated at the two conditions agreed within +/- 10% for the most volatile compounds. Generally, the ratios of emission rates at the low and high ventilation rates decreased with decreasing compound volatility. Changes in VOC emission rates in the manufactured houses over 2-9.5 months after installation varied by compound. Only several compounds showed a consistent decrease in emission rate over this period.     

MECHANISMS OF SYNFUEL DEGRADATION. I. EFFECTS OF ORGANIC NITROGEN COMPOUNDS ON THE STABILITY OF A SHALE DERIVED DIESEL FUEL

ABSTRACT

A reliable accelerated fuel stability teat regimen has been developed and applied to the study of the storage stability of a shale derived diesel fuel marine (DFM). The results of a survey of nitrogen compounds as dopants in a stable shale DFM base fuel indicate that 3ome pyrroles and indoles may play significant roles in storage stability. A complete stability test matrix has been developed for the temperatures of 43, 65 and 80°C, for time periods between A and 179 days, and for a ten-fold concentration range of a model dopant, 2,5-dimethylpyrrole (DMP). Stability was defined by the amount of total insoluble material (filterable sediment and adherent gum) produced after stress, and also by the amount of titratable peroxide present in the filtrates of stressed fuel samples. A very regular pattern for insolubles formation was found within the test matrix. Deposit formation rates exhibited a first-order dependence on DMP concentration, with an apparent activation energy of 11-12 kcal/mol. The sediment was found to contain 12% nitrogen and 18-20% oxygen irrespective of the stress conditions employed.     

CHARACTERIZATION AND STABILITY PROPERTIES OF POLAR EXTRACTS DERIVED FROM A RECENT SHALE LIQUID

ABSTRACT

A shale fuel of marginal stability has been used as a source of nitrogen-rich polar extracts. Polar compounds were isolated by mild acid extraction followed by silica gel adsorption and were identified by GC/HS. Alkyl substituted pyridines were the prevalent class of compounds present in most extracts. The effects of adding these shale derived fractions as dopants to a stable shale diesel fuel (0-11) were examined in terms of sediment formation and peroxide number under accelerated storage stability test conditions. The activities of the extracts in inducing fuel instability were correlated with their composition.     

DETERMINATION OF NITROGEN COMPOUND DISTRIBUTION FROM THREE SOURCE FUELS

ABSTRACT

As part of a world-wide survey of middle distillate fuel instability, three fuels were chosen for detailed GC/MS analysis. These fuels are identified by number and country of origin; FL-2577 was from Burnaby, British Columbia, Canada; FL-2599 was from Abamadj, Kuwait; and FL 2592 was from Chiba, Japan. The organo-nitrogen compounds in the three fuels were separated by mild acid extraction followed by silica gel absorption. This treatment yielded three fractions for each fuel; a basic nitrogen compounds fraction, BNC; a non-basic nitrogen compounds fraction in methylene chloride, mcl, NBNC-mcl; and a non-basic nitrogen compounds fraction in methanol, meoh, NBNC-meoh. The three fractions from each fuel were analyzed by combined capillary gc/ms. The organo-nitrogen compounds from each fraction were identified and quantitated.     

Soybean Biodiesel: Instability Reactions

Abstract

It has been suggested that renewable energy sources be considered as replacements for middle distillate ground transportation and marine fuels. It is vital for the operational considerations of these fuels to investigate the many positives and negatives of incorporating these renewable energy sources in such systems. In proposing such a replacement, considerations must be given to the many problems that could arise including fuel storage stability, fuel solubility, oxidative stability, and seawater stability. Contrary to air environments, water environments have a pH factor that has to be considered. United States Navy shipboard fuel tanks compensate for diminishing fuel by the addition of seawater to the fuel tank. It was found that this would lead to fuel instability problems such as filter stoppage and other serious engine damage. Studies were performed to determine what in the soybean-derived biodiesels led to the observed fuel degradation.