Fate of 1 to 6 nm Candle Combustion Nanoparticles in Indoor Atmospheric Environments

)─the ratio of the max-normalized net coagulation sink to the apparent emission rate─which effectively describes particle survival at specific sizes and offers a critical and previously lacking metric to evaluate nanoparticle persistence versus suppression in indoor environments. When this ratio exceeds 10, the concentration of 1-6 nm nanoparticles is suppressed by more than a hundred-fold. However, since this ratio typically remains <10 for most 1-6 nm nanoparticles, they persist at high concentrations, posing significant health risks due to their potential to penetrate deeply into the human respiratory tract, quantified through another novel parameter─the respiratory survival probability.