def GWP(CASRN, method=None):
r'''This function handles the retrieval of a chemical's Global Warming
Potential, relative to CO2. 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 GWP for the 100yr outlook by default.
Parameters
----------
CASRN : str
CASRN [-]
Returns
-------
GWP : float
Global warming potential, [(impact/mass chemical)/(impact/mass CO2)]
Other Parameters
----------------
method : string, optional
The method name to use. Accepted methods are IPCC (2007) 100yr',
'IPCC (2007) 100yr-SAR', 'IPCC (2007) 20yr', and 'IPCC (2007) 500yr'.
All valid values are also held in the variable `GWP_all_methods`.
Notes
-----
All data is from [1]_, the official source. Several chemicals are available
in [1]_ are not included here as they do not have a CAS.
Methods are 'IPCC (2007) 100yr', 'IPCC (2007) 100yr-SAR',
'IPCC (2007) 20yr', and 'IPCC (2007) 500yr'.
Examples
--------
Methane, 100-yr outlook
>>> GWP(CASRN='74-82-8')
25.0
See Also
--------
GWP_methods
References
----------
.. [1] 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.
'''
# TODO update with 5th edition values
# Official table is at https://www.ipcc.ch/site/assets/uploads/2018/02/WG1AR5_Chapter08_FINAL.pdf
# page 73
if not _GWP_ODP_data_loaded: _load_GWP_ODP_data()
if method:
key = _GWP_keys_by_method[method]
return retrieve_from_df(GWP_data, CASRN, key)
else:
return retrieve_any_from_df(GWP_data, CASRN,
_GWP_keys_by_method.values())
def ODP(CASRN, method=None):
r'''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
----------
CASRN : str
CASRN [-]
Returns
-------
ODP : float 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
----------------
method : string, 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'.
Examples
--------
Dichlorotetrafluoroethane, according to [2]_.
>>> ODP(CASRN='76-14-2')
0.58
References
----------
.. [1] US EPA, OAR. "Ozone-Depleting Substances." Accessed April 26, 2016.
https://www.epa.gov/ozone-layer-protection/ozone-depleting-substances.
.. [2] 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
'''
if not _GWP_ODP_data_loaded: _load_GWP_ODP_data()
if method:
key = _ODP_keys_by_method[method]
return retrieve_from_df(ODP_data, CASRN, key)
else:
return retrieve_any_from_df(ODP_data, CASRN,
_ODP_keys_by_method.values())