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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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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Endpoint:
phototransformation in air
Type of information:
calculation (if not (Q)SAR)
Remarks:
estimated by calculation
Adequacy of study:
key study
Study period:
1985
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Data calculated from several sources, limitations in reporting but considered reliable with restriction
Principles of method if other than guideline:
Measured data from author and other investigators were quality assessed and then used to develop rate constants for different chemicals. The author applied a least squares analysis of degradation rate constants to calculate a preferred value.
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material:
No data reported
Estimation method (if used):
Calculated half life based on a rate constant of 2.55E-12 cm^3 / molecule / sec, OH-radical concentration 5E+05 molecules.cm^-3 with 24 hour day, as specified in the TGD.
Light source:
not specified
Details on light source:
No data reported
Details on test conditions:
At 298K.
Reference substance:
not specified
Preliminary study:
No data reported
Test performance:
No data reported
Key result
DT50:
6.3 d
Test condition:
Calculated half life based on a rate constant of 2.55E-12 cm3 / molecule / sec
Transformation products:
not specified
Results with reference substance:
No data reported

N/A

Validity criteria fulfilled:
not specified
Conclusions:
The half life of butane has been estimated to be 6.3 days based on a recommended reaction rate with hydroxyl radicals and the concentration of hydroxyl radicals recommended in the Technical Guidance Document (2003).
Executive summary:

Measured data from author and other investigators were quality assessed and then used to develop rate constants for different chemicals. Therefore, this value represents a valid rate constant for butane based on all valid studies at the time of publication.

Endpoint:
phototransformation in air
Type of information:
calculation (if not (Q)SAR)
Remarks:
estimated by calculation
Adequacy of study:
key study
Study period:
1985
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Data calculated from several sources, limitations in reporting but considered reliable with restriction
Principles of method if other than guideline:
Measured data from author and other investigators were quality assessed and then used to develop rate constants for different chemicals. The author applied a least squares analysis of degradation rate constants to calculate a preferred value.
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material:
No data reported
Estimation method (if used):
Calculated half life based on a rate constant of 2.74 E-13 cm^3 / molecule / sec, OH-radical concentration 5E+05 molecules.cm^-3 with 24 hour day, as specified in the TGD.
Light source:
not specified
Details on light source:
No data reported
Details on test conditions:
At 298K.
Reference substance:
not specified
Preliminary study:
No data reported
Test performance:
No data reported
Key result
DT50:
58.6 d
Test condition:
Calculated half life based on a rate constant of 2.74 E-13 cm3 / molecule / sec
Transformation products:
not specified
Results with reference substance:
No data reported

N/A

Validity criteria fulfilled:
not specified
Conclusions:
The half life of ethane has been estimated to be 59 days based on a recommended reaction rate with hydroxyl radicals and the concentration of hydroxyl radicals recommended in the Technical Guidance Document (2003).
Executive summary:

Measured data from author and other investigators were quality assessed and then used to develop rate constants for different chemicals. Therefore, this value represents a valid rate constant for ethane based on all valid studies at the time of publication.

Endpoint:
phototransformation in air
Type of information:
calculation (if not (Q)SAR)
Remarks:
estimated by calculation
Adequacy of study:
key study
Study period:
1985
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Data calculated from several sources, limitations in reporting but considered reliable with restriction
Principles of method if other than guideline:
Measured data from author and other investigators were quality assessed and then used to develop rate constants for different chemicals. The author applied a least squares analysis of degradation rate constants to calculate a preferred value.
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material:
No data reported
Estimation method (if used):
Calculated half life based on a rate constant of 2.37E-12 cm^3 / molecule / sec, OH-radical concentration 5E+05 molecules.cm^-3 with 24 hour day, as specified in the TGD.
Light source:
not specified
Details on light source:
No data reported
Details on test conditions:
At 298K.
Reference substance:
not specified
Preliminary study:
No data reported
Test performance:
No data reported
Key result
DT50:
6.8 d
Test condition:
Calculated half life based on a rate constant of 2.37E-12 cm3 / molecule / sec
Transformation products:
not specified
Results with reference substance:
No data reported

N/A

Validity criteria fulfilled:
not specified
Conclusions:
The half life of isobutane has been estimated to be 6.8 days based on a recommended reaction rate with hydroxyl radicals and the concentration of hydroxyl radicals recommended in the Technical Guidance Document (2003).
Executive summary:

Measured data from author and other investigators were quality assessed and then used to develop rate constants for different chemicals. Therefore, this value represents a valid rate constant for isobutane based on all valid studies at the time of publication.

Endpoint:
phototransformation in air
Type of information:
calculation (if not (Q)SAR)
Remarks:
estimated by calculation
Adequacy of study:
key study
Study period:
1985
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Data calculated from several sources, limitations in reporting but considered reliable with restriction
Principles of method if other than guideline:
Measured data from author and other investigators were quality assessed and then used to develop rate constants for different chemicals. The author applied a least squares analysis of degradation rate constants to calculate a preferred value.
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material:
No data reported
Estimation method (if used):
Calculated half life based on a rate constant of 8.41E-15 cm^3 / molecule / sec, OH-radical concentration 5E+05 molecules.cm^-3 with 24 hour day, as specified in the TGD.
Light source:
not specified
Details on light source:
No data reported
Details on test conditions:
At 298K.
Reference substance:
not specified
Preliminary study:
No data reported
Test performance:
No data reported
Key result
DT50:
1 907 d
Test condition:
Calculated half life based on a rate constant of 8.41E-15 cm3 / molecule / sec
Transformation products:
not specified
Results with reference substance:
No data reported

N/A

Validity criteria fulfilled:
not specified
Conclusions:
The half life of methane has been estimated to be 1907 days based on a recommended reaction rate with hydroxyl radicals and the concentration of hydroxyl radicals recommended in the Technical Guidance Document (2003).
Executive summary:

Measured data from author and other investigators were quality assessed and then used to develop rate constants for different chemicals. Therefore, this value represents a valid rate constant for methane based on all valid studies at the time of publication.

Endpoint:
phototransformation in air
Type of information:
calculation (if not (Q)SAR)
Remarks:
estimated by calculation
Adequacy of study:
key study
Study period:
1985
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Data calculated from several sources, limitations in reporting but considered reliable with restriction
Principles of method if other than guideline:
Measured data from author and other investigators were quality assessed and then used to develop rate constants for different chemicals. The author applied a least squares analysis of degradation rate constants to calculate a preferred value.
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material:
No data reported
Estimation method (if used):
Calculated half life based on a rate constant of 1.18E-12 cm^3 / molecule / sec, OH-radical concentration 5E+05 molecules.cm^-3 with 24 hour day, as specified in the TGD.
Light source:
not specified
Details on light source:
No data reported
Details on test conditions:
At 298K.
Reference substance:
not specified
Preliminary study:
No data reported
Test performance:
No data reported
Key result
DT50:
14 d
Test condition:
Calculated half life based on a rate constant of 1.18E-12 cm3 / molecule / sec
Transformation products:
not specified
Results with reference substance:
No data reported

N/A

Validity criteria fulfilled:
not specified
Conclusions:
The half life of propane has been estimated to be 14 days based on a recommended reaction rate with hydroxyl radicals and the concentration of hydroxyl radicals recommended in the Technical Guidance Document (2003).
Executive summary:

Measured data from author and other investigators were quality assessed and then used to develop rate constants for different chemicals. Therefore, this value represents a valid rate constant for propane based on all valid studies at the time of publication.

Description of key information

The phototransformation in air half-lives of the substances in the category range from 1907 to 6.3 days.

Key value for chemical safety assessment

Additional information

Data from Atkinson (1985) were available for the substances methane, ethane, propane, butane and isobutane. Measured data from author and other investigators were quality assessed and then used to develop rate constants for different chemicals. Therefore, this value represents a valid rate constant for the substances based on all valid studies at the time of publication.

The phototransformation half-life of methane is 1907 days, ethane is 59 days, propane is 14 days, butane is 6.3 days and isobutane is 6.8 days.