Cotton pillow samplers for assessment of thirdhand smoke in homes of smokers and nonsmokers with children.

Secondhand smoke (SHS) exposure is a major source of illnesses in children and leaves a persistent and toxic residue indoors called thirdhand smoke (THS) that deposits on surfaces, is absorbed into materials, collects in house dust, and is re-emitted into the air. THS, like SHS, has been shown to contain multiple toxic chemicals including carcinogenic tobacco-specific nitrosamines (TSNAs). Children are highly susceptible to tobacco smoke pollutants, and simple methods for assessing children's SHS and THS exposure are needed. Therefore, we evaluated the performance of a cotton pillow used as a passive sampler in homes of children with caregivers who smoke tobacco, with and without home smoking bans, as well as nonsmokers. We deployed a commercially available organic cotton travel pillow, which was left in the home for a median 9.1 days. Pillow component nicotine levels were significantly higher in homes of smokers without a ban as compared to smokers and nonsmokers who had a ban (e.g., median pillowcase nicotine 337.7 ng/g per day vs. 72.5 ng/g per day and 0.1 ng/g per day, respectively) and differences were similar to those for air nicotine. Pillowcase TSNAs were detected mainly in the homes of smokers without a smoking ban. Pillow component (pillowcase, fabric, and filling) nicotine levels were highly correlated with air nicotine levels (rho=0.76-0.88, all p<0.001). Nicotine in the pillow components was also highly correlated with urinary cotinine in the children (rho=0.65 to 0.81, all p<0.001) and other measures of tobacco smoke exposure. Pillow performance as a sampler is promising, given the ease and simplicity of sample deployment.