Environmental Properties (chemicals.environment)

This module contains lookup functions for three important environmental properties - Global Warming Potential, Ozone Depletion Potential, and octanol-water partition coefficient.

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Global Warming Potential

chemicals.environment.GWP(CASRN, method=None)

This function handles the retrieval of a chemical’s Global Warming Potential, relative to CO2. Lookup is based on CASRNs.

There are four sources of data:

• IPCC Sixth Assessment Report (AR5) from 2021 [4]

• IPCC Fifth Assessment Report (AR5) from 2014 [2]

• IPCC Fourth Assessment Report (AR4) from 2007 [1]

• IPCC Second Assesment Report or (SAR) from 1995 [1]

This function returns the GWP for the 20yr outlook from the AR6 by default.

Parameters

CASRNstr

CASRN [-]

Returns

GWPfloat

Global warming potential, [(impact/mass chemical)/(impact/mass CO2)]

Other Parameters

methodstr, optional

The method name to use. Accepted methods are (‘IPCC (2021) 100yr’, ‘IPCC (2021) 20yr’, ‘IPCC (2021) 500yr’, ‘IPCC (2014) 100yr’, ‘IPCC (2014) 20yr’, ‘IPCC (2007) 100yr’, ‘IPCC (2007) 20yr’, ‘IPCC (2007) 500yr’, ‘IPCC (1995) 100yr’). All valid values are also held in the variable GWP_all_methods.

See also

GWP_methods

Notes

“Fossil methane” is included in the IPCC reports to take into account different isotopic composition, but as that has the same CAS number it is not included in this function.

Six of the entries in [2] are actually duplicates; the entries with data similar to more recent data [3] were prefered.

References

1(1,2)

IPCC. “2.10.2 Direct Global Warming Potentials - AR4 WGI Chapter 2: Changes in Atmospheric Constituents and in Radiative Forcing.” 2007. https://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch2s2-10-2.html.

2(1,2)

IPCC. “Climate Change 2013: The Physical Science Basis. - AR5 WGI Chapter 8: Anthropogenic and Natural Radiative Forcing.” 2013. https://www.ipcc.ch/site/assets/uploads/2018/02/WG1AR5_Chapter08_FINAL.pdf

3

Hodnebrog, Ø., B. Aamaas, J. S. Fuglestvedt, G. Marston, G. Myhre, C. J. Nielsen, M. Sandstad, K. P. Shine, and T. J. Wallington. “Updated Global Warming Potentials and Radiative Efficiencies of Halocarbons and Other Weak Atmospheric Absorbers.” Reviews of Geophysics 58, no. 3 (2020): e2019RG000691. https://doi.org/10.1029/2019RG000691.

4

Masson-Delmotte, Valérie, Panmao Zhai, Anna Pirani, Sarah L. Connors, Clotilde Péan, Sophie Berger, Nada Caud, Yang Chen, Leah Goldfarb, and Melissa I. Gomis. “Climate Change 2021: The Physical Science Basis.” Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change 2 (2021): 24.

Examples

Methane, 20-yr outlook AR6

>>> GWP(CASRN='74-82-8')
81.2

Methane, specifying the default method explicitly (this is recommended the default data source may be updated in the future)

>>> GWP(CASRN='74-82-8', method='IPCC (2014) 100yr')
28.0

Methane, 20-year values from 1995 and 2007

>>> (GWP(CASRN='74-82-8', method='IPCC (1995) 100yr'), GWP(CASRN='74-82-8', method='IPCC (2007) 100yr'))
(21.0, 25.0)

chemicals.environment.GWP_methods(CASRN)

Return all methods available to obtain GWP for the desired chemical.

Parameters

CASRNstr

CASRN, [-]

Returns

methodslist[str]

Methods which can be used to obtain GWP with the given inputs.

See also

GWP

chemicals.environment.GWP_all_methods = ('IPCC (2014) 100yr', 'IPCC (2014) 20yr', 'IPCC (2007) 100yr', 'IPCC (2007) 20yr', 'IPCC (2007) 500yr', 'IPCC (1995) 100yr', 'IPCC (2021) 20yr', 'IPCC (2021) 100yr', 'IPCC (2021) 500yr')

Tuple of method name keys. See the GWP for the actual references

Global Temperature Potential

chemicals.environment.GTP(CASRN, method=None)

This function handles the retrieval of a chemical’s Global Temperature Potential, relative to CO2. Lookup is based on CASRNs.

There are two sources of data:

• IPCC Sixth Assessment Report (AR5) from 2021 [2]

• IPCC Fifth Assessment Report (AR5) from 2014 [1]

This function returns the GTP for the 50yr outlook from the AR6 by default.

Parameters

CASRNstr

CASRN [-]

Returns

GTPfloat

Global temperature potential, [(impact/mass chemical)/(impact/mass CO2)]

Other Parameters

methodstr, optional

The method name to use. Accepted methods are (‘IPCC (2021) 100yr’, ‘IPCC (2021) 50yr’, ‘IPCC (2014) 100yr’, ‘IPCC (2014) 20yr’, ‘IPCC (2014) 50yr’). All valid values are also held in the variable GTP_all_methods.

See also

GTP_methods

References

1

IPCC. “Climate Change 2013: The Physical Science Basis. - AR5 WGI Chapter 8: Anthropogenic and Natural Radiative Forcing.” 2013. https://www.ipcc.ch/site/assets/uploads/2018/02/WG1AR5_Chapter08_FINAL.pdf

2

Masson-Delmotte, Valérie, Panmao Zhai, Anna Pirani, Sarah L. Connors, Clotilde Péan, Sophie Berger, Nada Caud, Yang Chen, Leah Goldfarb, and Melissa I. Gomis. “Climate Change 2021: The Physical Science Basis.” Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change 2 (2021): 24.

Examples

Methane, 50-yr outlook AR6

>>> GTP(CASRN='74-82-8')
11.0

chemicals.environment.GTP_methods(CASRN)

Return all methods available to obtain GTP for the desired chemical.

Parameters

CASRNstr

CASRN, [-]

Returns

methodslist[str]

Methods which can be used to obtain GTP with the given inputs.

See also

GTP

chemicals.environment.GTP_all_methods = ('IPCC (2014) 20yr', 'IPCC (2014) 50yr', 'IPCC (2014) 100yr', 'IPCC (2021) 50yr', 'IPCC (2021) 100yr')

Tuple of method name keys. See the GTP for the actual references

Ozone Depletion Potential

chemicals.environment.ODP(CASRN, method=None)

This function handles the retrieval of a chemical’s Ozone Depletion Potential, relative to CFC-11 (trichlorofluoromethane). Lookup is based on CASRNs. Will automatically select a data source to use if no method is provided; returns None if the data is not available.

Returns the ODP of a chemical according to [2] when a method is not specified. If a range is provided in [2], the highest value is returned.

Parameters

CASRNstr

CASRN [-]

Returns

ODPfloat or str

Ozone Depletion potential, [(impact/mass chemical)/(impact/mass CFC-11)]; if method selected has string in it, this will be returned as a string regardless of if a range is given or a number

Other Parameters

methodstr, optional

The method name to use. Accepted methods are ‘ODP2 Max’, ‘ODP2 Min’, ‘ODP2 string’, ‘ODP2 logarithmic average’, and methods for older values are ‘ODP1 Max’, ‘ODP1 Min’, ‘ODP1 string’, and ‘ODP1 logarithmic average’. All valid values are also held in the list ODP_methods.

Notes

Values are tabulated only for a small number of halogenated hydrocarbons, responsible for the largest impact. The original values of ODP as defined in the Montreal Protocol are also available, as methods with the ODP1 prefix.

All values are somewhat emperical, as actual reaction rates of chemicals with ozone depend on temperature which depends on latitude, longitude, time of day, weather, and the concentrations of other pollutants.

All data is from [1]. Several mixtures listed in [1] are not included here as they are not pure species. Methods for values in [2] are ‘ODP2 Max’, ‘ODP2 Min’, ‘ODP2 string’, ‘ODP2 logarithmic average’, and methods for older values are ‘ODP1 Max’, ‘ODP1 Min’, ‘ODP1 string’, and ‘ODP1 logarithmic average’.

References

1(1,2)

US EPA, OAR. “Ozone-Depleting Substances.” Accessed April 26, 2016. https://www.epa.gov/ozone-layer-protection/ozone-depleting-substances.

2(1,2,3,4)

WMO (World Meteorological Organization), 2011: Scientific Assessment of Ozone Depletion: 2010. Global Ozone Research and Monitoring Project-Report No. 52, Geneva, Switzerland, 516 p. https://www.wmo.int/pages/prog/arep/gaw/ozone_2010/documents/Ozone-Assessment-2010-complete.pdf

Examples

Dichlorotetrafluoroethane, according to [2].

>>> ODP(CASRN='76-14-2')
0.58

chemicals.environment.ODP_methods(CASRN)

Return all methods available to obtain ODP for the desired chemical.

Parameters

CASRNstr

CASRN, [-]

Returns

methodslist[str]

Methods which can be used to obtain ODP with the given inputs.

See also

ODP

chemicals.environment.ODP_all_methods = ('ODP2 Max', 'ODP1 Max', 'ODP2 logarithmic average', 'ODP1 logarithmic average', 'ODP2 Min', 'ODP1 Min', 'ODP2 string', 'ODP1 string')

Tuple of method name keys. See the ODP for the actual references

Octanol-Water Partition Coefficient

chemicals.environment.logP(CASRN, method=None)

This function handles the retrieval of a chemical’s octanol-water partition coefficient. Lookup is based on CASRNs. Will automatically select a data source to use if no method is provided; returns None if the data is not available.

Parameters

CASRNstr

CASRN [-]

Returns

logPfloat

Octanol-water partition coefficient, [-]

Other Parameters

methodstr, optional

The method name to use. Accepted methods are ‘SYRRES’, ‘CRC’, and ‘WIKIDATA’. All valid values are also held in the list logP_methods.

Notes

Although matimatically this could be expressed with a logarithm in any base, reported values are published using a base 10 logarithm.

$$\log_{10} P_{ oct/wat} = \log_{10}\left(\frac{\left[{solute} \right]_{ octanol}^{un-ionized}}{\left[{solute} \right]_{ water}^{ un-ionized}}\right)$$

References

1

Syrres. 2006. KOWWIN Data, SrcKowData2.zip. http://esc.syrres.com/interkow/Download/SrcKowData2.zip

2

Haynes, W.M., Thomas J. Bruno, and David R. Lide. CRC Handbook of Chemistry and Physics, 95E. Boca Raton, FL: CRC press, 2014.

Examples

>>> logP('67-56-1')
-0.74
>>> logP('100-66-3', 'WIKIDATA')
2.11

chemicals.environment.logP_methods(CASRN)

Return all methods available to obtain logP for the desired chemical.

Parameters

CASRNstr

CASRN, [-]

Returns

methodslist[str]

Methods which can be used to obtain logP with the given inputs.

See also

logP

chemicals.environment.logP_all_methods = ('SYRRES', 'CRC', 'WIKIDATA')

Tuple of method name keys. See the logP for the actual references