Measurement report: Firework impacts on air quality in Metro Manila, Philippines, during the 2019 New Year revelry
Authors: Lorenzo Genevieve Rose , Bañaga Paola Angela , Cambaliza Maria Obiminda , Cruz Melliza Templonuevo , AzadiAghdam Mojtaba , Arellano Avelino , Betito Grace , Braun Rachel , Corral Andrea F. , Dadashazar Hossein , Edwards Eva-Lou , Eloranta Edwin , Holz Robert , Leung Gabrielle , Ma Lin , MacDonald Alexander B. , Reid Jeffrey S. , Simpas James Bernard , Stahl Connor , Visaga Shane Marie , Sorooshian Armin 
Published: April 2021

Abstract. Fireworks degrade air quality, reduce visibility, alter atmospheric
chemistry, and cause short-term adverse health effects. However, there have
not been any comprehensive physicochemical and optical measurements of
fireworks and their associated impacts in a Southeast Asia megacity, where
fireworks are a regular part of the culture. Size-resolved particulate
matter (PM) measurements were made before, during, and after New Year 2019
at the Manila Observatory in Quezon City, Philippines, as part of the Cloud,
Aerosol, and Monsoon Processes Philippines Experiment (CAMP2Ex). A high-spectral-resolution lidar (HSRL) recorded a substantial increase in
backscattered signal associated with high aerosol loading ∼440 m above the surface during the peak of firework activities around 00:00 (local time). This was accompanied by PM2.5 concentrations peaking at
383.9 µg m−3. During the firework event, water-soluble ions
and elements, which affect particle formation, growth, and fate, were mostly
in the submicrometer diameter range. Total (>0.056 µm)
water-soluble bulk particle mass concentrations were enriched by 5.7 times
during the fireworks relative to the background (i.e., average of before and
after the firework). The water-soluble mass fraction of PM2.5 increased by 18.5 % above that of background values. This corresponded
to increased volume fractions of inorganics which increased bulk
particle hygroscopicity, kappa (κ), from 0.11 (background) to 0.18
(fireworks). Potassium and non-sea-salt (nss) SO42- contributed
the most (70.9 %) to the water-soluble mass, with their mass size
distributions shifting from a smaller to a larger submicrometer mode during
the firework event. On the other hand, mass size distributions for
NO3-, Cl−, and Mg2+ (21.1 % mass contribution) shifted
from a supermicrometer mode to a submicrometer mode. Being both uninfluenced
by secondary aerosol formation and constituents of firework materials, a
subset of species were identified as the best firework tracer species (Cu,
Ba, Sr, K+, Al, and Pb). Although these species (excluding K+)
only contributed 2.1 % of the total mass concentration of water-soluble
ions and elements, they exhibited the highest enrichments (6.1 to 65.2)
during the fireworks. Surface microscopy analysis confirmed the presence of
potassium/chloride-rich cubic particles along with capsule-shaped particles
in firework samples. The results of this study highlight how firework
emissions change the physicochemical and optical properties of water-soluble
particles (e.g., mass size distribution, composition, hygroscopicity, and
aerosol backscatter), which subsequently alters the background aerosol's
respirability, influence on surroundings, ability to uptake gases, and
viability as cloud condensation nuclei (CCN).