An Approach to Tentative Reference Levels Setting for Nanoparticles in the Workroom Air Based on Comparing Their Toxicity with That of Their Micrometric Counterparts: A Case Study of Iron Oxide Fe₃O₄

Table 3

Percentage distribution of phagocytising cells with various degrees of particle burden 24 hours after intratracheal instillation of suspensions of magnetite particle (2 mg/mL) of various sizes to rats (𝑥±s.e.).

Alveolar macrophages (%%)		Neutrophil leucocytes (%%)
with ≤20 particles	with >20 particles	with ≤20 particles	with >20 particles
24 hours after administration of 10 nm particles.
9.38 ± 0.25%^b	90.62 ± 0.35%^b	42.66 ± 0.28%^b	57.34 ± 0.38%^b
24 hours after administration of 50 nm particles.
19.09 ± 0.21%^ab	80.91 ± 0.21%^ab	72.55 ± 0.18%^ab	27.45 ± 0.19%^ab
24 hours after administration of 1000 nm particles.
64.00 ± 0.16%^a	36.00 ± 0.16%^a	97.75 ± 0.08%^a	2.25 ± 0.08%^a

^aDesignates values that are statistically significantly different from values of the “10 nm” group; ^bthe same from the value for the group of rats administered 1000 nm particles (𝑃<0.001 by 𝑡-test allowing for standard error of complex means, whereby data for each rat are considered as a sample consisting of 𝑛 cells).