5.1 In order to estimate ETS concentrations, there needs to be a marker or tracer for ETS that is unique or highly specific to tobacco smoke, in sufficient concentrations in air to be measured easily at realistic smoking rates, and in constant proportion to the other components of ETS for a variety of tobacco blends and environmental conditions. Nicotine and 3-ethenylpyridine have been used as tracers of the vapor phase of ETS. Nicotine is the major alkaloid of tobacco and a major constituent of ETS. The determination of nicotine concentration has often been used to estimate the concentration of ETS; however, due to its unpredictable decay kinetics, nicotine may not be an ideal tracer. Because nicotine readily adsorbs to building materials and room furnishings and is depleted from ETS at a rate faster than most other components, some have suggested that nicotine concentrations underestimate ETS concentrations. Although this is true in many environments during the generation of smoke, the converse is true in environments with a recent past history of smoking. The adsorbed nicotine slowly desorbs over time, resulting in an overestimation of ETS concentrations. Thus, measured concentrations of nicotine precisely assess only airborne nicotine and indicate only that smoking has taken place; they do not necessarily indicate the presence, and certainly not the concentrations, of other ETS constituents. 3-Ethenylpyridine, on the other hand, has been shown to track exactly the vapor phase of ETS as measured by CO and FID response (3). It is for these reasons that 3-ethenylpyridine may be a better tracer of ETS (1, 4, 5). The ETS at high concentrations is known to be annoying and irritating to individuals, and concerns over potential health effects have also been expressed. There is a definite need to have reliable methods for the estimation of ETS levels in order to evaluate its effect. The NIOSH has previously set a recommended exposure limit (REL) for nicotine in the workplace of 0.5 mg/m³.

5.2 Studies show that more than 90 % of nicotine in indoor air is found in the vapor phase (6, 7). The described test method collects vapor-phase nicotine quantitatively. Early studies on freshly generated ETS indicated that some but not all of the particulate phase was trapped on the resin (7). A more recent investigation of the trapping of particulate materials by sorbent beds suggests that the trapping of the particles from indoor air may be nearly quantitative (8). 3-Ethenylpyridine is found exclusively in the vapor phase.

5.3 Nicotine concentrations typically range from ND (not detected) to 70 μg/m³ in various indoor environments with values usually at the lower end of this range (9). Because such low concentrations of nicotine are often encountered, sophisticated analytical procedures and equipment are required for quantifying nicotine in indoor air. Other methods for the determination of nicotine in indoor air have also been reported (6, 10, 11, 12). 3-Ethenylpyridine concentrations typically are about one third the concentrations of nicotine in real-world environments (13).

1.1 This test method covers the sampling/analysis of nicotine and 3-ethenylpyridine (3-EP) in indoor air. This test method is based upon the collection of nicotine and 3-EP by adsorption on a sorbent resin, extraction of nicotine and 3-EP from the sorbent resin, and determination by gas chromatography (GC) with nitrogen selective detection. (1)2

1.2 The active samplers consist of an macroreticular polystyrene-divinylbenzene copolymer (for example, XAD-4) sorbent tube attached to a sampling pump. Macroreticular polystyrene-divinylbenzene copolymer is referred to “sorbent resin” throughout this method. This test method is applicable to personal or area sampling.

1.3 This test method is limited in sample duration by the capacity of the sorbent tube for nicotine (about 300 μg). This test method has been evaluated up to 24-h sample duration; however, samples are typically acquired for at least 1 h (sometimes only 1 h). (2)

1.4 For this test method, limits of detection (LOD) and quantitation (LOQ) for nicotine at a sampling rate of 1.5 L/min are, respectively, 0.11 μg/m³ and 0.37 μg/m ³ for 1-h sample duration and 0.01 μg/m³ and 0.05 μg/m³ for 8-h sample duration. The LOD and LOQ for 3-EP at a sampling rate of 1.5 L/min are, respectively, 0.06 μg/m ³ and 0.19 μg/m³ for 1-h sample duration and 0.01 μg/m³ and 0.02 μg/m³ for 8-h sample duration (2). Both LOD and LOQ can be reduced by increasing the sensitivity of the thermionic specific detector.

1.5 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific precautionary information is given in 13.6.