Fine particles from Independence Day fireworks events: chemical characterization and source apportionment

Abstract. To study the impact of fireworks (FW) events on air quality, aerosol particles from FW displays were measured using a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and collocated instruments during the Independence Day (July 4) holiday 2017 at Albany, NY, USA. Three FW events were identified through the potassium ion (K⁺) signals in the aerosol mass spectra. The largest FW event signal measured at two different sites was the Independence Day celebration in downtown Albany, with maximum hourly PM_2.5 of about 55 μg m⁻³ at the downtown site (approximately 1 km from the FW launch location), and 33.3 μg m⁻³ of non-refractory PM₁ at the uptown site (approximately 8 km downwind). The aerosol concentration peak measured at the uptown site occurred 2 hours later than at the downtown site. The Independence Day FW events resulted in significant increases in both organic and inorganic (K⁺, sulfate, chloride) chemical components. Positive Matrix Factorization (PMF) of organics mass spectra identified one FW related organic aerosol factor (FW-OOA) with a highly oxidized state. The intense emission of FW particles from the Independence Day celebration contributed about 79.0 % (26.1 μg m⁻³) of total PM₁ (33.0 μg m⁻³) measured at the uptown site during Independence Day FW event (07/04 23:00–07/05 02:00). Aerosol measurements and wind LiDAR measurements showed two distinct pollution sources, one from the Independence Day FW event in Albany, and the other transported from the northeast, potentially associated with another city’s FW events. This study highlights the significant influence of FW burning on fine aerosol mass concentration and chemical characteristics, which is useful in quantifying the impacts of FW on air pollution, at a time when more than usual people are clustered together and breathing the outdoor air.