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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Environmental fate & pathways

Phototransformation in air

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Administrative data

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Endpoint:
phototransformation in air
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
test procedure in accordance with generally accepted scientific standards and described in sufficient detail
Principles of method if other than guideline:
Method: other (measured): critical review (data mostly measured according to methods developed by Atkinson and coworkers)
GLP compliance:
no
% Degr.:
50
Sampling time:
6 h
Test condition:
OH radical conc. 500000 molec/cm³
Transformation products:
not measured
K[OH] =  64 [10E-12 cm3 molecule-1 s-1]
K[NO3] = 9.74[10E-12 cm3 molecule-1 s-1]
K[O3] = 1.9 [10E-19 cm3 molecule-1 s-1] With a OH radical concentration of 1 000 000 molec/mL, the
half-life is 3.0 h at room temperature (6 h at 500000 molec/mL)
Validity criteria fulfilled:
not specified
Conclusions:
The tropospheric half-life of m-cresol is approximately 6 h due to degradation by OH radicals with an average concentration of 500000 radicals/mL.
Executive summary:

The tropospheric half-life of m-cresol is approximately 6 h due to degradation by OH radicals with an average concentration of 500000 radicals/mL.

Endpoint:
phototransformation in air
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
test procedure in accordance with generally accepted scientific standards and described in sufficient detail
Principles of method if other than guideline:
Method: other (measured)
GLP compliance:
no
Light spectrum: wavelength in nm:
ca. 450
Reference substance:
yes
Remarks:
1,3-butadiene or o-cresol 0.05-2.3 ppm
% Degr.:
50
Sampling time:
3.8 h
Test condition:
OH radical conc. 1000000 molec/cm³
Transformation products:
not measured
kOH = 5.17 x 10E-12 exp[(686+-231)/T] cm3 molec.-1 s-1 for a
temperature range of 299-373
With a OH radical concentration of 1 000 000 molec cm-3 and
a temperature of 299 K, the half-life is 3.8 h
Validity criteria fulfilled:
not applicable
Conclusions:
A half-life of 3.8 h at 26°C is calculated for m-cresol from smoke chamber experiments at different tempertures.
Executive summary:

A half-life of 3.8 h at 26°C is calculated for m-cresol from smoke chamber experiments at different tempertures.

Description of key information

The tropospheric half-life of m-cresol is approximately 6 h due to degradation by OH radicals with an average concentration of 500000 radicals/mL .
An even shorter half-life of 3.8 h is calculated for m-cresol from smoke chamber experiments at different tempertures.

Key value for chemical safety assessment

Half-life in air:
6 h
Degradation rate constant with OH radicals:
0 cm³ molecule-1 s-1

Additional information

In the atmosphere, m-cresol will react with photochemically produced hydroxyl-radicals. In his critical review Atkinson recommended values for the reaction constant kOH at room temperature of 6.4 x 10-11 cm³ x molecule-per second. Based on a tropospheric OH radical concentration of 5 x 105molecules per cm³ a corresponding half-life of 6.0 h can be calculated.

In an experiment the temperature dependency of the reaction constants in a smog chamber was determined. The calculated half-life is 3.8 h for m-cresol at 23°C.