A pilot study using scripted ventilation conditions to identify key factors affecting indoor pollutant concentration and air exchange rate in a residence

Abstract

A pilot study was conducted using an occupied, single-family test house in Columbus, OH, to determine whether a script-based protocol could be used to obtain data useful in identifying the key factors affecting air-exchange rate (AER) and the relationship between indoor and outdoor concentrations of selected traffic-related air pollutants. The test script called for hourly changes to elements of the test house considered likely to influence air flow and AER, including the position (open or closed) of each window and door and the operation (on/off) of the furnace, air conditioner, and ceiling fans. The script was implemented over a 3-day period (January 30-February 1, 2002) during which technicians collected hourly-average data for AER, indoor, and outdoor air concentrations for six pollutants (benzene, formaldehyde (HCHO), polycyclic aromatic hydrocarbons (PAH), carbon monoxide (CO), nitric oxide (NO), and nitrogen oxides (NO x )), and selected meteorological variables. Consistent with expectations, AER tended to increase with the number of open exterior windows and doors. The 39 AER values measured during the study when all exterior doors and windows were closed varied from 0.36 to 2.29 h À1 with a geometric mean (GM) of 0.77 h À1 and a geometric standard deviation (GSD) of 1.435. The 27 AER values measured when at least one exterior door or window was opened varied from 0.50 to 15.8 h À1 with a GM of 1.98 h À1 and a GSD of 1.902. AER was also affected by temperature and wind speed, most noticeably when exterior windows and doors were closed. Results of a series of stepwise linear regression analyses suggest that (1) outdoor pollutant concentration and (2) indoor pollutant concentration during the preceding hour were the ''variables of choice'' for predicting indoor pollutant concentration in the test house under the conditions of this study. Depending on the pollutant and ventilation conditions, one or more of the following variables produced a small, but significant increase in the explained variance (R 2 -value) of the regression equations: AER, number and location of apertures, wind speed, air-conditioning operation, indoor temperature, outdoor temperature, and relative humidity. The indoor concentrations of CO, PAH, NO, and NO x were highly correlated with the corresponding outdoor concentrations. The indoor benzene concentrations showed only moderate correlation with outdoor benzene levels, possibly due to a weak indoor source. Indoor formaldehyde concentrations always exceeded outdoor levels, and the correlation between indoor and outdoor concentrations was not statistically significant, indicating the presence of a strong indoor source.

Hazard assessment of chemical air contaminants measured in residences

“…Tables Table 1 Publications (Turpin et al 2007) 48 hrs Los Angeles; Houston; Elizabeth, NJ,US X P X X 157-275 17 (Croxford et al 2006) 1 week London, UK C 270 18 (Jia et al 2008) 3-4 days Michigan, US X X X 251-257 19 (Jo and Lee 2006) 2 hrs Daegu, South Korea C 240 20 (Heroux et al 2009) 24 hrs Saskatchewan, Canada X X NA 217 21 (Long et al 2000) 12 hrs Boston, Massachusetts, US X P 211 22 (Offermann 2009) 24 hrs California, US X X P,C, N X X X 31-211 23 (Jarvis et al 2005) 14 days United Kingdom N 203 24 (Edwards et al 2001) 48 hrs Helsinki, Finland X X X 201 25 (Gordon et al 1999) 6-7 days Arizona, US X X 185 26 (Jia et al 2008) 3-4 days Southeast Michigan, US X X X NA 159 27 (Sexton et al 2004) 2 days Minneapolis/St. Paul, Minnesota, US X X 132 28 (Rudel et al 2003) 24 hrs Cape Cod, Massachusetts, US X X 30-120 29 (Fromme et al 2004) 7-8 hrs Berlin, Germany X 115 30 (Simons et al 2007) 3 days Baltimore, Maryland, US X O, P, N 95-109 31 (Weisel 2006) 24 hrs New Jersey, US X X 7-100 32 (Zota et al 2005) 2 weeks Boston, Massachusetts, US X N 100 33 (Guo et al 2009) 24 hrs Hong Kong X X 100 34 (Gilbert et al 2006) 7 days Quebec City, Canada N X 96 36 (Miller et al 2009) 24 hrs Commerce City, Colorado, US X C,P 92-97 37 (Phillips et al 2005) 24 hrs Oklahoma, US X X 90 38 (Kinney et al 2002) 48 hrs West central Harlem, New York, US X P X X X 18-88 39 (Lee et al 2002) 6 days Southern California, US X N,O 92-106 40 (Sorensen et al 2005) 48 hrs Copenhagen, Denmark P,N 73-87 41 (Dodson et al 2008) 24 hrs Boston, Massachusetts, US X X X 83 42 (Janssen et al 2005) 24 hrs Amsterdam/Helsinki P X 82 43 (Garrett et al 1999) 24 hrs Latrobe Valley, Victoria, Australia N 80 44 24 hrs Ottawa, Ontario, Canada X X 75 45 (Raymer et al 2009) 24 hrs Wisconsin, California, US X X X 47-70 46 (Johnson et al 2004) 3 days Columbus, Ohio, US X C 32-67 47 …”

Influence of indoor formaldehyde pollution on respiratory system health in the urban area of Shenyang, China

“…There are some ways to reduce the concentration of formaldehyde indoors, such as choosing environmentally-friendly decorating materials, ensuring thorough ventilation, delaying residency, and installing cleansing equipment [16][17][18] . Our study confirmed that the use of environmentally-friendly decorating materials, longer storage of materials after decoration, and increased ventilation helped to reduce formaldehyde pollution.…”

Measurement of air exchange rates in different indoor environments using continuous CO2 sensors

“…Some studies reported AERs using perfluorocarbon tracer (PFT) compounds (Dietz et al, 1981(Dietz et al, , 1986Leaderer et al, 1985;Cheong and Riffat, 1995). The most commonly used method is the sulfur hexafluoride (SF 6 ) decay test, which has been reported in many studies (McBride et al, 1997;Johnson et al, 2004) when commercial availability of instruments for SF 6 tests has made AER measurements possible. However, the instrumentation for these methods is usually bulky and expensive.…”