Table 5.

Percent of measurement data and predicted intensities (for the evaluated exposure determinant scenarios) exceeding various thresholds^a

Solvent	No.b	Median (p.p.m.)	Range (p.p.m.)	Percent exceeding thresholdc
				ACGIH TLV	0.01% SVP	0.1% SVP	1% SVP
Methylene chloride
Measurement data	1272	7.0	0.0004–2200	23	22	1.0	0
Predicted intensity	192	2.8	0.051–160	4.7	4.2	0	0
1,1,1-trichloroethane
Measurement data	947	0.95	0.0004–1500	2.1	18	3.8	0
Predicted intensity	432	0.67	0.0013–200	0	9.7	0.2	0
Trichloroethylene
Measurement data	484	7.0	0.0002–1100	45	46	10	0.2
Predicted intensity	480	30	0.21–3700	71	65	28	3.1d

^aTo evaluate the models, a long-term personal predicted intensity was computed for each unique combination of inputs (exposure determinants and year) to the Table 4 prediction models. To avoid extrapolation errors due to limited data, years prior to 1970 were not evaluated for methylene chloride and 1,1,1-trichloroethane and years prior to 1950 were not evaluated for trichloroethylene. The midpoint of the decade was used as the year in these predictions. For example, for the methylene chloride model, there were 2 × 2 × 2 × 2 × 2 × 2 = 64 unique combinations of the exposure determinants and three decades (1970s, 1980s, and 1990s); consequently, 64 × 3 = 192 unique scenarios were evaluated.

^bNumber of reported levels for measurement data and number of exposure determinant scenarios evaluated for predicted intensities.

^cThresholds include the current ACGIH TLVs [50 p.p.m. (established in 1988), 350 p.p.m. (established in 1963), and 10 p.p.m. (established in 2006) for methylene chloride, 1,1,1-trichloroethane, and trichloroethylene, respectively] and 0.01, 0.1 and 1% of the SVP (at 25°C, is 572 386, 161 370, and 90 789 p.p.m. for methylene chloride, 1,1,1-trichloroethane, and trichloroethylene, respectively).

^dAll scenarios exceeding 1% of the SVP for trichloroethylene were from the 1950s–1970s.