Figure 4
From: High concentrations of flavor chemicals are present in electronic cigarette refill fluids
Heat Map and Cytotoxicity of Flavor Chemicals >10 mg/ml. (a) The x-axis of the heat map shows individual refill fluid products with at least one flavor chemical >10 mg/ml. Total flavor concentration decreases from left to right. The y-axis is ordered from high to low toxicity for the individual flavor chemicals based on the LD50 oral dose for rats (from peer reviewed articles on the Good Scents database (www.thegoodscentscompany.com) and grouped according to the European CLP regulation criteria; harmful; irritant, and not determined (ND). Concentration of individual flavor chemicals >1 mg/ml are shown as yellow cells and >10 mg/ml are orange to red cells. The country of each product’s origin is designated on the x-axis labels by U = USA, N = Nigeria, C = China, and B = Britain. Cinnamaldehyde is abbreviated CAD*. Dose-response curves for menthol (b) and ethyl maltol (c) tested with hPF and BEAS-2B cells in the MTT assay. The highest concentration of each flavor chemical tested is 10% of that found in the refill fluid. Each point is the mean ± standard error of the mean of three independent experiments. Points with letters are significantly different from the untreated control and points with different letters show degrees of statistical significance. ap < 0.05, bp < 0.01, cp < 0.001, dp < 0001.
