In:
Atmospheric Chemistry and Physics, Copernicus GmbH, Vol. 20, No. 3 ( 2020-02-07), p. 1531-1547
Abstract:
Abstract. Relationships between various optical, physical, and chemical properties of
biomass-combustion-derived particles are characterized for particles
produced in the laboratory from a wide range of fuels and burn conditions.
The modified combustion efficiency (MCE), commonly used to parameterize
biomass particle emissions and properties, is shown to generally have weak
predictive capabilities, especially for more efficient combustion
conditions. There is, however, a strong relationship between many intensive
optical properties (e.g., single-scatter albedo, Ångström absorption
exponent, mass absorption efficiency) and the organic aerosol-to-black
carbon ([OA] ∕ [BC]) mass ratio over a wider range than previously considered
(0.3 to 105). The properties of brown carbon (BrC, i.e., light-absorbing organic carbon) also vary with [OA] ∕ [BC]. Coating-induced enhancements
(i.e., “lensing” effects) contribute only a minor amount to BC absorption
for all of the burns despite some burns producing particles having large
ensemble-average coating-to-core mass ratios. The BC–OA mixing state varies
strongly with [OA] ∕ [BC]; the fraction of OA that is internally mixed with BC
decreases with [OA] ∕ [BC] while the relative amount of OA coated on BC
increases. In contrast, there is little relationship between many OA bulk
chemical properties and [OA] ∕ [BC], with the O : C and H : C atomic ratios and
the relative abundance of a key marker ion (m/z=60, linked to
levoglucosan) all showing no dependence on [OA] ∕ [BC]. In contrast, both the
organic nitrate fraction of OA and the OA volatility do depend on the
[OA] ∕ [BC]. Neither the total particle nor BC-specific size distributions
exhibit any clear dependence on the burn conditions or [OA] ∕ [BC], although
there is perhaps a dependence on fuel type. Overall, our results expand on
existing knowledge to contribute new understanding of the properties of
particles emitted from biomass combustion.
Type of Medium:
Online Resource
ISSN:
1680-7324
DOI:
10.5194/acp-20-1531-2020
DOI:
10.5194/acp-20-1531-2020-supplement
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2020
detail.hit.zdb_id:
2092549-9
detail.hit.zdb_id:
2069847-1
