emission compartments in brightway and how they are implemented - brightway

Question

I wanted to identify the emissions to air of an activity in Brightway but exploring this lead me to a more general question. Are compartments and subcompartments taken into account in the implementation of impact assessment methods?
In principle the emission factors depend on the compartment, for example is not the same thing to emit formaldehyde to water or air. Taking as example impact 2002 endpoint human health method. according to the spreadsheet provided by ecoinvent LCIA implementation_3.3, the CF is 3 orders of magnitude higher in air. If I check the implementation in the same method in Brightway:
m_name=[m for m in bw.methods if '2002' in str(m)
and 'human toxicity' in str(m)][0]
m=bw.Method(m_name)
# Generate the dictionary using a comprehension:
m_dict = {bw.get_activity(ef[0])['name']:ef[1] for ef in m.load()}
# put the whole thing in a neat Pandas series
m_series=pd.Series(m_dict,
name="{}, {}".format(m.name, m.metadata['unit']))
m_series[m_series.index.str.contains('Formaldehyde')]
I only find the value corresponding to emission to water, but no info on the compartment / subcompartment. What am I missing?

Answer 1

There aren't any real requirements for what metadata should be associated with a biosphere flow (or any node) in Brightway2, but the key categories is populated in the default metadata:
In [1]: import brightway2 as bw
In [2]: for flow in bw.Database("biosphere3"):
...: if 'formaldehyde' in flow['name'].lower():
...: print(flow['name'], flow['categories'])
...:
Formaldehyde ('water',)
Formaldehyde ('air', 'lower stratosphere + upper troposphere')
Formaldehyde ('water', 'ocean')
Formaldehyde ('water', 'surface water')
Formaldehyde ('water', 'ground-')
Formaldehyde ('air', 'low population density, long-term')
Formaldehyde ('water', 'ground-, long-term')
Formaldehyde ('air', 'urban air close to ground')
Formaldehyde ('air',)
Formaldehyde ('air', 'non-urban air or from high stacks')
Both emissions to air and water are characterized in ('IMPACT 2002+ (Endpoint)', 'human health', 'total'):
In [3]: name = ('IMPACT 2002+ (Endpoint)', 'human health', 'total')
In [4]: for key, cf in bw.Method(name).load():
...: flow = bw.get_activity(key)
...: if 'formaldehyde' in flow['name'].lower():
...: print(flow, cf)
...:
'Formaldehyde' (kilogram, None, ('air', 'low population density, long-term')) 0.00180414
'Formaldehyde' (kilogram, None, ('air', 'non-urban air or from high stacks')) 0.00180414
'Formaldehyde' (kilogram, None, ('air',)) 0.00180414
'Formaldehyde' (kilogram, None, ('air', 'urban air close to ground')) 0.00180414
'Formaldehyde' (kilogram, None, ('water', 'surface water')) 8.1879e-06
'Formaldehyde' (kilogram, None, ('water',)) 8.1879e-06