Personal exposure to ultrafine particles

Abstract

Personal exposure to ultrafine particles (UFP) can occur while people are cooking, driving, smoking, operating small appliances such as hair dryers, or eating out in restaurants. These exposures can often be higher than outdoor concentrations. For 3 years, portable monitors were employed in homes, cars, and restaurants. More than 300 measurement periods in several homes were documented, along with 25 h of driving two cars, and 22 visits to restaurants. Cooking on gas or electric stoves and electric toaster ovens was a major source of UFP, with peak personal exposures often exceeding 100,000 particles/cm 3 and estimated emission rates in the neighborhood of 10 12 particles/min. Other common sources of high UFP exposures were cigarettes, a vented gas clothes dryer, an air popcorn popper, candles, an electric mixer, a toaster, a hair dryer, a curling iron, and a steam iron. Relatively low indoor UFP emissions were noted for a fireplace, several space heaters, and a laser printer. Driving resulted in moderate exposures averaging about 30,000 particles/cm 3 in each of two cars driven on 17 trips on major highways on the East and West Coasts. Most of the restaurants visited maintained consistently high levels of 50,000-200,000 particles/cm 3 for the entire length of the meal. The indoor/outdoor ratios of size-resolved UFP were much lower than for PM 2.5 or PM 10 , suggesting that outdoor UFP have difficulty in penetrating a home. This in turn implies that outdoor concentrations of UFP have only a moderate effect on personal exposures if indoor sources are present. A time-weighted scenario suggests that for typical suburban nonsmoker lifestyles, indoor sources provide about 47% and outdoor sources about 36% of total daily UFP exposure and in-vehicle exposures add the remainder (17%). However, the effect of one smoker in the home results in an overwhelming increase in the importance of indoor sources (77% of the total). Keywords: cooking, restaurants, gas stoves, electric stoves, vehicles, tobacco smoke. IntroductionUltrafine particles (UFP) are increasingly studied because of considerations of their toxicology and possible human health effects (Oberdo¨rster et al., 2005; Bra¨uner et al., 2007a, b;Sto¨lzel et al., 2007). Outdoor UFP concentrations were measured for 1-2 years in several US cities (U.S. EPA Supersites program; Solomon et al., 2008), and near roadways in California (Zhu et al., 2002) and also in Erfurt and Augsberg, Germany (Wichmann et al., 2000). Residential indoor concentrations have also been reported (Abt et al., 2000;Dennekamp et al., 2001;Long et al., 2001;Wallace and Howard-Reed, 2002;Klepeis et al., 2003;He et al., 2004;Wallace, 2000Wallace, , 2005Wallace, , 2006Wallace et al., 2004Wallace et al., , 2008Hoek et al., 2008). A number of studies of exposures while driving have been done (Westerdahl et al., 2005;Fruin et al., 2008;Zhu et al., 2008). However, exposures in locations such as restaurants or while operating everyday sources of UFP close to one's person (stoves, toasters, ovens, hair dryers...

Outdoor fine and ultrafine particle measurements at six bus stops with smoking on two California arterial highways—Results of a pilot study

“…In their experiment with 22,973 1-sec readings from collocated monitors, they reported the coefficient of determination between the two monitors of R 2 ¼ 0.998. Wallace and Ott (2011) reported that the bulk of the particle size distribution of tobacco smoke by number count lies between 0.01 and 0.45 mm, which is within the 0.01-1.0 mm size range that the TSI-3007 measures (Hämeri et al, 2002;TSI, 2013b). Other investigators using the TSI-3007 condensation particle counter in and near traffic have referred to their measurements as "ultrafine particles" (Westerdahl et al, 2005;Jarjour et al, 2013;Quiros et al, 2013); although this instrument includes counts above the UFP range (>0.1 mm), we will use the term UFP in this paper to refer to these measurements.…”

“…Wallace and Ott (2011) report a quality control comparison between two TSI-3007 monitors run side-by-side for 100 hr to determine their precision and relative bias. They found that the relative bias was 1-3%, and the mean of their relative precision, calculated as the sum of the absolute value of the differences divided by the sum of each measured pair, was 2.3%.…”

“…One of many sources of exposure to ultrafine particles (UFP) is secondhand tobacco smoke (Wallace and Ott, 2011). Because of their very small size, UFP have a higher predicted deposition rate in the human respiratory tract than larger particles (Daigle et al, 2003;Obersdörster and Utell, 2002).…”

Footprints of Airborne Ultrafine Particles on Urban Air Quality and Public Health

“…They estimated relative contribution to the typical 24 h daily nonsmoker style exposures by outdoor, indoor and in-vehicle sources as 36, 47 and 17%, respectively. This contribution was doubled for indoor (77%), nearly halved for outdoor (17%) and one-third for in-vehicle (6%) in the presence of a smoker smoking on an average 16 cigarettes per day in an averaged size house having volume of 400 m 3 and typical air exchange rates of about 0.75 h -1 [7]. As expected, the exposure contribution from outdoor sources can decrease in rural areas and increase in urban areas due to a greater mobility of road vehicles.…”

“…After the switching off indoor sources, concentration decay generally occurs at a much slower rate due to the surrounding built up environment restricting the ventilation and dilution. A recent study, based on suburban areas in USA, characterised the indoor sources in detail [7]. They estimated relative contribution to the typical 24 h daily nonsmoker style exposures by outdoor, indoor and in-vehicle sources as 36, 47 and 17%, respectively.…”