Variabilities in Primary N-Containing Aromatic Compound Emissions from Residential Solid Fuel Combustion and...

Area of Science:

• Environmental Chemistry
• Atmospheric Science
• Public Health

Background:

• Nitroaromatic compounds (NACs) are potent chromophores with adverse human health effects.
• NACs originate from incomplete combustion and secondary photochemical reactions.
• Understanding NAC emission factors (EF∑NACs) and sources is crucial for air quality management.

Purpose of the Study:

• To investigate variations and influencing factors of NAC emission factors (EF∑NACs) across different fuel-stove combinations.
• To identify potential chemical tracers for distinguishing between combustion sources.
• To explore the health and climate implications of differing NAC profiles.

Main Methods:

• Conducted emission experiments using 31 fuel-stove combinations.
• Quantified total NACs (∑NACs) and individual compound abundances.
• Analyzed emission profiles to differentiate between coal and biomass burning.

Main Results:

• EF∑NACs varied by two orders of magnitude, with fuel type being a greater influence than stove type.
• Biomass pellets showed significantly lower EF∑NACs compared to raw biomass.
• Distinct NAC profiles were observed: biomass burning favored phenolic compounds (e.g., 4-nitrocatechol), while coal combustion produced more two-ring products (e.g., 2-nitro-1-naphthol).
• The ratio of 2-nitro-1-naphthol/4-nitrocatechol was substantially lower for biomass (2.0–3.0) than for coal (15).

Conclusions:

• Fuel type is a primary driver of NAC emissions and their chemical profiles.
• The ratio of 2-nitro-1-naphthol/4-nitrocatechol serves as a reliable tracer for source apportionment of NACs from coal versus biomass combustion.
• Divergent NAC profiles from different sources lead to distinct environmental and health impacts.