Characteristics of particulate matter during New Year's eve fireworks and Taal volcano ashfall in Metro Manila on January 2020

In this study, we describe the chemical and physical characteristics of two air pollution events in the first half of January 2020 in Metro Manila, Philippines, namely the New Year's eve fireworks and the Taal volcano ashfall. During the New Year's eve fireworks, PM2.5 concentration and most of the chemical components increased three-fold. However, we found disproportionately higher increases for certain metallic components typically used as pyrotechnic propellant and/or colorant for blue, white, and green light: Fe(5-fold), Cr(5-fold), Cu(8-fold), Ni(9-fold), V(10-fold), Ti(11-fold), and Ba(34-fold). These results provide insights for health assessments and legislation related to fireworks emissions. On January 12, 2020, the Taal volcano eruption caused much concern in Metro Manila as visible tephra deposits were observed. There was only a slight in-crease (8%) in PM2.5 concentration and its components related to basaltic ash. The low PM2.5 concentration was mainly due to the inhibited intrusion of ash into the stable nocturnal boundary layer. In addition, the detection of lightning in the plume and umbrella region showed size segregation of ash particles. The WRF-Chem model was able to capture the distribution of both tephra advection and fallout, a first for Taal volcano, making it possible for use in the future ashfall forecasting.