Styrene

Phototransformation in air

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

phototransformation in air

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

The reaction of styrene with ozone in the vapor phase have been investigated in static and dynamic systems.

GLP compliance:

no

Light source:

not specified

DT50:

9.2 h

Transformation products:

not specified

Rate constant cm³• molecule^-1• s^-1: 2.99 • 10^-17.

Half-life: 9.2 hours.

Validity criteria fulfilled:

not applicable

Executive summary:

Styrene was tested for phototransformation in air. The Rate constant was determined to be 2.99 • 10^-17 cm3 • molecule^-1• s^-1 and the Half-live is 9.2 h.

Reference 2

Endpoint:

phototransformation in air

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Qualifier:

no guideline followed

Principles of method if other than guideline:

The experimental technique, is based on observing the increased rate of ozone decay in the presence of a known excess of a reactive compound.

GLP compliance:

no

Light source:

not specified

Details on test conditions:

Reactions were carried out in a -175- liter volume Teflon bag, constructed out of a 2-mil thick, 180 X 140 cm FEP Teflon sheet, heat sealed around the edges, and fitted with Teflon injection and sampling ports at each end of the bag. Initial O3 concentrations were 12.40 X 1013 molecule cm-3, and the O3 concentrations were monitored as a function of time after mixing of the reactants by a Monitor Labs model 8410 chemiluminescent ozone analyzer. Background ozone decay rates, in the absence of the reactants, were determined periodically during these rate constant determinations.
The organic reactant concentrations in the entire bag were calculated from the amount of organic introduced and the total volume of air used to fill the Teflon bag. It was observed that for the alkenes, both gaseous and liquid, these calculated organic concentrations agreed to within better than ±10% with the concentrations quantitatively measured by gas chromatography. All reactions were carried out at room temperature

Reference substance:

not specified

DT50:

12.7 h

Transformation products:

not specified

Tropospheric ozone rapidly degrade styrene in the atmosphere.

 

Rate constant cm³·molecule^-1·s^-1: 2.16 · 10^-17

Half-life: 12.7 h

Validity criteria fulfilled:

not applicable

Executive summary:

Styrene was tested for phototransformation in air. The Rate constant was determined to be 2.16 · 10^-17 cm3 • molecule^-1• s^-1 and the Half-live is 12.7 h.

 

Reference 3

Endpoint:

phototransformation in air

Type of information:

other: review data

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Qualifier:

no guideline followed

Principles of method if other than guideline:

Review data with no special reference to the method used in the experiments with styrene

GLP compliance:

no

Light source:

not specified

DT50:

7.4 h

Transformation products:

not specified

Rate constant cm3 • molecule^-1• s^-1: 5.2 ± 0.5.10^-11.

Half-life: 7.4 hours.

Validity criteria fulfilled:

not applicable

Executive summary:

Styrene was tested for phototransformation in air. The Rate constant was determined to be 5.2 ± 0.5.10^-11 cm3 • molecule^-1• s^-1 and the Half-live is 7.4 h.

Description of key information

After evaporation or exposure to the air, the product will be rapidly degraded by photochemical processes.

Half-lives of 7.4 hours for the reaction with hydroxyl radicals and of 9.2 hours for reaction with ozone have been calculated (Atkinson 1985, Bufalini & Altshuller 1965). 

Key value for chemical safety assessment

Half-life in air:

9.2 h

Additional information

Styrene does not adsorb solar radiation appreciably at wavelengths greater than 300 nm, therefore degradation of styrene in air and water by direct photolysis is unlikely.

Hydroxyl radicals and tropospheric ozone rapidly degrade styrene in the atmosphere. Half-lives of 7.4 hours for the reaction with hydroxyl radicals and of 9.2 hours for reaction with ozone have been calculated (Atkinson 1985, Bufalini & Altshuller 1965).