Volatile pollutants emitted from selected liquid household products

BACKGROUND, AIM, AND SCOPE: To identify household products that may be potential sources of indoor air pollution, the chemical composition emitted from the products should be surveyed. Although this kind of survey has been conducted by certain research groups in Western Europe and the USA, there is still limited information in scientific literature. Moreover, chemical components and their proportions of household products are suspected to be different with different manufacturers. Consequently, the current study evaluated the emission composition for 42 liquid household products sold in Korea, focusing on five product classes (deodorizers, household cleaners, color removers, pesticides, and polishes). MATERIALS AND METHODS: The present study included two phase experiments. First, the chemical components and their proportions in household products were determined using a gas chromatograph and mass spectrometer system. For the 19 target compounds screened by the first phase of the experiment and other selection criteria, the second phase was done to identify their proportions in the purged-gas phase. RESULTS: The number of chemicals in the household products surveyed ranged from 9 to 113. Eight (product class of pesticides) to 17 (product class of cleaning products) compounds were detected in the purged-gas phase of each product class. Several compounds were identified in more than one product class. Six chemicals (acetone, ethanol, limonene, perchloroethylene (PCE), phenol, and 1-propanol) were identified in all five product classes. There were 13 analytes occurring with a frequency of more than 10% in the household products: limonene (76.2%), ethanol (71.4%), PCE (66.7%), phenol (40.5%), 1-propanol (35.7%), decane (33%), acetone (28.6%), toluene (19.0%), 2-butoxy ethanol (16.7%), o-xylene (16.7%), chlorobenzene (14.3%), ethylbenzene (11.9%), and hexane (11.9%). All of the 42 household products analyzed were found to contain one or more of the 19 compounds. DISCUSSION: The chemical composition varied broadly along with the product classes or product categories, and it was different from that reported in other studies abroad, although certain target chemicals were identified in both studies. This finding supports an assertion that chemical components emitted from household products may be different in different products and with different manufacturers. The chlorinated pollutants identified in the present study have not been reported to be components of cleaning products in papers published since the early 1990s. Limonene was identified as having the highest occurrence in the household products in the present study, although it was not detected in any of 67 household products sold in the U.S. CONCLUSIONS: The emission composition of selected household products was successfully examined by purge-and-trap analysis. Along with other exposure information such as use pattern of household products and the indoor climate, this composition data can be used to estimate personal exposure levels of building occupants. This exposure data can be employed to link environmental exposure to health risk. It is noteworthy that many liquid household products sold in Korea emitted several toxic aromatic and chlorinated organic compounds. Moreover, the current finding suggests that product types and manufacturers should be considered, when evaluating building occupants' exposure to chemical components emitted from household products. RECOMMENDATIONS AND PERSPECTIVES: The current findings can provide valuable information for the semiquantitative estimation of the population inhalation exposure to these compounds in indoor environments and for the selection of safer household products. However, although the chemical composition is known, the emissions of household products might include compounds formed during the use of the product or compounds not identified as ingredients by this study. Accordingly, further studies are required, and testing must be done to determine the actual composition being emitted. Similar to eco-labeling of shampoos, shower gels, and foam baths proposed by a previous study, eco-labeling of other household products is suggested.     

Sequential production of pyrolytic oil and biodiesel from oil-bearing biomass

Oil extraction from the oil-bearing biomass and waste materials has been considered as one of the biggest challenges in the biodiesel production process because it has been considered as the most energy- and cost-demanding step. This work provides a promising approach for the direct transformation without oil extraction from calcined montmorillonite clay (CMC) and microalgae by means of the non-catalytic thermo-chemical process in conjunction with the real continuous flow system. The introduced method showed the high tolerance of water, impurities, and free fatty acids (FFAs), which enable the combination of the esterification of FFAs and transesterification of triglycerides into a single step without the lipid extraction. For example, this study showed that the maximum achievable yield of biodiesel via the introduced methodology was 97 ± 0.5 % at the temperature regime of 380–480 °C and this biodiesel yield was enhanced in the presence of CO₂. Thus, the introduced methodology for producing biodiesel could be an alternative way of the methanol liquefaction and transesterification under supercritical conditions.     

Mutagenic activity of river water from a river near textile industrial complex in Korea

The mutagenic activity of XAD-2 adsorbates and water extracts recovered from nine locations of the Kumho River was tested on S. typhimurium TA98 strain to identify the source of the mutagenicity. A sampling site, receiving effluents from the textile industrial complex located in Daegu City, showed extraordinarily high mutagenic activity, especially in the presence of S9 mixture, at all sampling time in both XAD-2 adsorbates and dichloromethane extracts. This indicated the existence of the frame-shift mutagens in the Kumho River, same type of mutagens detected in previous studies by other researchers in the Nakdong River into which the Kumho River discharges. The fractionation study showed that the mutagenic chemicals in the river water are mid-polar. Furthermore, mean tail length obtained by single cell gel electrophoresis assay (Comet assay) showed consistent dose-dependent DNA damage, indicating that the chemicals in the river water not only act as frame-shift mutagens but also break human lymphocytes DNA strain. Chemical identification of the mutagens should be required.     

Concentrations and source characteristics of airborne carbonyl compounds measured outside urban residences

This paper presents the analysis of ambient air concentrations of 10 carbonyl compounds (aldehydes and ketones) measured in the yards of 87 residences in the city of Elizabeth, NJ, throughout 1999-2001. Most of these residences were measured twice in different seasons; the sampling duration was 48 hr each time. The authors observed higher concentrations for most of the measured carbonyl compounds on warmer days, reflecting larger contributions of photochemical reactions on warmer days. The estimated contributions of photochemical production varied substantially across the measured carbonyl compounds and could be as high as 60%. Photochemical activity, however, resulted in a net loss for formaldehyde. The authors used stepwise multiple linear regression models to evaluate the impact of traffic sources and meteorological conditions on carbonyl concentrations using the data collected on colder days (with lower photochemical activities). They found that the concentrations of formaldehyde, acetaldehyde, acrolein, propionaldehyde, crotonaldehyde, benzaldehyde, glyoxal, and methylglyoxal significantly decreased with increasing distance between a measured residence and one or more major roadways. They also found significant negative associations between concentrations for most of the measured carbonyl compounds and each of the following meteorological parameters: mixing height, wind speed, and precipitation.     

A new recycling material for removing phosphorus from water

In search of readily available and relatively inexpensive materials for phosphorus removal, waste oyster shell is a waste product from oyster-culturing farm and also presents a major disposal problem in itself. Activated oyster shell produced by pyrolysis at 750 °C exhibits promising performance as a suitable substance for phosphorus removal. The capacity of the activated oyster shell, in terms of equivalents of OH^? per gram of material, is about 80% than that of calcium hydroxide. However, the granular nature of activated oyster shell (AOS) makes it much easier to handle than lime. This would be a very important advantage for treatment facilities that cannot afford specialized powder handling facilities necessary for lime. Another advantage of AOS is its time-release properties, which can allow it to be added to reactors intermittently and still achieve consistent phosphate precipitation. Distribution of phosphate after contact with AOS indicates that adsorption does not play a significant role in phosphate removal with AOS. Rather, it appears that the phosphate is precipitated in the presence of Ca²⁺ and high pH as a key mechanism. Since it is produced from a waste product of mariculture, AOS is a sustainable precipitant for phosphate removal.     

The Effects of Local Cooling on Thermophysiological Response in Participants Wearing Dust-Free Garments

This study was designed to find the effects of two kinds of dust-free garments with (A) and without (B) frozen gel strip (FGS), and half-naked clothing (brassiere and shorts; C) on thermophysiological parameters and on temperature and humidity within clothing. The heart rate, rectal, and skin temperatures as well as sweat rate and clothing microclimate were measured during 140 min in 9 healthy females. Inquiries were also made into the subjective rating of thermal, humidity, and comfort sensations. The main findings in our experiments are as follows: (a) Physiological parameters such as rectal and skin temperatures (chest and forehead), heart rate, and sweat rate were clearly lowest in garb C, intermediate in garb A, and highest in garb B throughout the experiment; (b) Temperature and humidity within clothing were lower in garb A than in garb B; (c) More than half of the 9 participants decreased thermal sensation by wearing garb A. These results suggest that the usage of FGS could improve the heat load in lightly working participants wearing dust-free garments.     

A Classification System for Characterization of Physical and Non-Physical Work Factors

A comprehensive evaluation of work-related perfomance factors is a prerequisite to developing integrated and long-term solutions to workplace performance improvement. This paper describes a work-factor classification system that categorizes the entire domain of workplace factors impacting performance. A questionnaire-based instrument was developed to implement this classification system in industry. Fifty jobs were evaluated in 4 different service and manufacturing companies using the proposed questionnaire-based instrument. The reliability coefficients obtained from the analyzed jobs were considered good (.589 to .862). In general, the physical work factors resulted in higher reliability coefficients (.847 to .862) than non-physical work factors (.589 to .768). performance work-factor system classification     

Novel method for determining pyrene biodegradation using synchronous fluorimetry

To study the biodegradation rate of pyrene dissolved in liquid medium supplemented with mineral salts, a synchronous fluorimetry (SF) method was established. The limit of detection for pyrene dissolved in mineral salts medium (MSM) was determined as 0.19 ng/ml with a relative standard deviation of less than 1.3% (n = 9). The pyrene degrading rates of four bacterial strains were investigated using this method under the same experimental conditions. The degradation rates of the three active strains ranged from 76% to 87% after a 14-h incubation. The results were confirmed by the gas chromatography with a flame ionized detector (GC/FID) method. This implies that pyrene degradation can be directly monitored by the SF method without the solvent extraction of samples. The advantages of SF are that it is less laborious, faster, and less expensive than the GC/FID determination method with solvent extraction. The SF method provides a new tool for studying the degradation of polynuclear aromatic hydrocarbons (PAHs) in the natural environment and under experimental conditions.     

Adsorption and photocatalytic degradation of bisphenol A using TiO2 and its separation by submerged hollowfiber ultrafiltration membrane

This study evaluates the adsorption ability ofbisphenol A（BPA） on titanium dioxide（TiO2） and its effect on the photocatalysis by advanced oxidation process using UV radiation and TiO2 photocatalyst. Degradation of BPA was also evaluated for the system without adsorption prior to photocatalytic reaction. The separation of TiO2 from BPA solution treated by pilot-scale photocatalytic reactor （capacity 0.16 m^3） was studied using submerged ultrafiltration （UF） membrane. It was found that although adsorption capacity of BPA was not high, adsorption played an important role in improving the efficiency ofphotocatalysis. On the other hand, during the separation of TiO2 particles from aqueous suspension, the permeate flux of the membrane was strongly affected by transmembrane pressure and TiO2 dose. The permeate turbidity was decreased below 1 NTU.