Changes in the concentration of volatile organic compounds and aldehydes in newly constructed houses over time

Abstract

Nowadays, people spend most of their time indoors; thus, the indoor environment greatly affects human health because of exposure to chemicals indoors. Thus, in collaboration with Japanese house builders, a list of building materials having low volatile organic compound concentrations was compiled herein. The air-quality samples from seven newly built houses (seven bedrooms and seven living rooms) were collected and tested for 64 volatile organic compounds and two aldehydes. Air samples were obtained from the house with no furniture or household goods and were sampled 1 week after construction and repeated after a month. Furthermore, the test results with a 2009 survey of indoor air quality in newly constructed houses were compared. One week after construction, the xylene, styrene, toluene, formaldehyde, and ethylbenzene concentrations were less than half the standard guideline values set in Japan. The main substances detected in the samples were 2-butanone, acetone, ethanol, ethyl acetate, butyl acetate, and undecane. The statistical significance of the changes in substance concentrations over time was examined via Wilcoxon signed-rank test. One month after construction, the concentrations of all chemical substances had undergone a statistically significant reduction, except butyl acetate. The median of total volatile organic compounds in living rooms was 291 µg/m 3 , and the maximum was 354 µg/m 3 ; both were under Japan's provisional total volatile organic compound target of 400 µg/m 3 . These values were significantly lower than those recorded by other researchers. This study concludes that using experimentally identified low volatile organic compound materials effectively improves the indoor air quality.

Concentrations of Formic Acid, Acetic Acid, and Ammonia in Newly Constructed Houses

“…The mean, standard deviation (SD), maximum, and minimum values of temperature, and the relative humidity of each room investigated in this study, are listed in Table 1. Since air samplings were conducted before the residents moved in, the air conditioner was off during the sampling so that the temperature indoors could reach 7 or 8 • C. Table 2 demonstrates the levels of formic acid, acetic acid, and ammonia in air samples from living rooms, bedrooms, and outdoor areas in this study and previous studies [22]. These compounds were detected in all the samples analyzed in this study.…”

“…Overall, 47 houses were selected from 49 houses that were used as test sites for our previous study [22]. Air samples from these locations were captured and analyzed for the presence of organic acids and ammonia.…”

“…SVOCs were analyzed via GC/MS spectrometry after ultrasonic extraction. The levels of those substances in indoor and outdoor air were previously reported [22]. These measurements were performed in compliance with the "Indoor Air-Sampling strategy for volatile organic compounds (VOCs)" by JIS A 1965 and 1966 [23].…”

“…One mechanism of formic acid generation is thought to be the oxidation process of formaldehyde [33,34]. Because the floors were covered with laminated flooring in the test sites, and the mean value of 15 µg m −3 of formaldehyde was detected [22], it is likely that the formic acid in indoor air samples herein was emitted directly from building materials or generated by the reaction of formaldehyde inside or on the building material surface. Its concentration levels in indoor air samples were low (Table 2), and it accounted for a small percentage of the sum of VOCs, from 4.2% to 4.6% (Figure 1), herein.…”

Indoor Air Quality Analysis of Newly Built Houses

“…There is thus a risk that consumers will be exposed to high chemical concentrations if the indoor air of their newly built houses is contaminated, since new-build houses have high concentrations of various VOCs emitted by building materials and products [11,12]. In our previous study [17], we assessed IAQ by measuring the levels of five compounds (styrene, formaldehyde, ethylbenzene, toluene, and xylene) for which the MLIT’s Housing Quality Assurance Act sets out guideline values, as well as the total amount of VOCs (TVOC). Our results showed that it is possible to achieve good IAQ with low VOC concentrations, much lower than the Act’s guideline values, even just after construction is completed by using low-emission materials and maintaining ventilation rates of more than 0.5 air changes per hour, as required by Japanese law.…”