Comparison of carcinogen, carbon monoxide, and ultrafine particle emissions from narghile waterpipe and cigarette smoking: Sidestream smoke measurements and assessment of second-hand smoke emission factors

Abstract

The lack of scientific evidence on the constituents, properties, and health effects of second-hand waterpipe smoke has fueled controversy over whether public smoking bans should include the waterpipe. The purpose of this study was to investigate and compare emissions of ultrafine particles (UFP, <100 nm), carcinogenic polyaromatic hydrocarbons (PAH), volatile aldehydes, and carbon monoxide (CO) for cigarettes and narghile (shisha, hookah) waterpipes. These smoke constituents are associated with a variety of cancers, and heart and pulmonary diseases, and span the volatility range found in tobacco smoke.Sidestream cigarette and waterpipe smoke was captured and aged in a 1 m(3) Teflon-coated chamber operating at 1.5 air changes per hour (ACH). The chamber was characterized for particle mass and number surface deposition rates. UFP and CO concentrations were measured online using a fast particle spectrometer (TSI 3090 Engine Exhaust Particle Sizer), and an indoor air quality monitor. Particulate PAH and gaseous volatile aldehydes were captured on glass fiber filters and DNPH-coated SPE cartridges, respectively, and analyzed off-line using GC-MS and HPLC-MS. PAH compounds quantified were the 5- and 6-ring compounds of the EPA priority list. Measured aldehydes consisted of formaldehyde, acetaldehyde, acrolein, methacrolein, and propionaldehyde.We found that a single waterpipe use session emits in the sidestream smoke approximately four times the carcinogenic PAH, four times the volatile aldehydes, and 30 times the CO of a single cigarette. Accounting for exhaled mainstream smoke, and given a habitual smoker smoking rate of 2 cigarettes per hour, during a typical one-hour waterpipe use session a waterpipe smoker likely generates ambient carcinogens and toxicants equivalent to 2-10 cigarette smokers, depending on the compound in question. There is therefore good reason to include waterpipe tobacco smoking in public smoking bans.

Figure 1

Schematic of a narghile waterpipe. The head, body, water bowl, and hose are the primary elements from which the waterpipe is assembled. Tobacco is loaded into the head, and burning charcoal is placed on top of the tobacco. When a user inhales from the mouthpiece, air and hot charcoal fumes are convected through the tobacco, raising its temperature, and generating the desired smoke. The smoke exits from the bottom of the head, into the body, and through the bubbler and hose to the user. The waterpipe illustrated here, and used in this study, is configured for use with sweetened and flavored tobacco, known as ma’ssel. When ma’ssel is used, a relatively deep (approximately 3 cm) head is filled with 10–20 g of the flavored tobacco mixture and covered with an aluminum foil sheet that is perforated for air passage. Burning charcoal is placed on top of the aluminum foil to provide the heat needed to generate the smoke. Similar quantities of charcoal and tobacco mixture are consumed in a typical 1 h café use session. (Figure adapted from Monzer et al., 2008.)

Figure 2

Schematic of the experimental setup used in this study. Air change (1.5 ACH) is driven by computer-controlled sampling trains located on the right hand side of the chamber. SS enters the chamber from the roof of the dilution tunnel, and HEPA-filtered lab air enters at the bottom of the tunnel. All surfaces are Teflon^® coated.

Figure 3

Typical frequency functions for cigarette and waterpipe SS. A larger fraction of waterpipe SS is found below 100 nm.

Figure 4

(a and b) Particle number distribution in chamber for standard waterpipe smoking condition (charcoal with tobacco), charcoal-only condition (waterpipe smoked with no tobacco in the head), and tobacco alone (by difference) at t = 5 and 20 min after start of smoking session. Charcoal is shown to be a major contributor of UFP in waterpipe SS.

Figure 5

Typical total (5.6–560 nm) particle concentration versus time for waterpipe and cigarette cases. An additional half charcoal briquette is added at 30 min, resulting in a second concentration peak. Waterpipe is removed from the tunnel at 56 min.