Air Quality and Characterization of Microplastic Presence in Moss Plant in Intramuros, Manila, Philippines/ Catrina D. Castro, Jan Yzabel A. Gaza, Samantha H. Gierza, Keith Brian M. Hizon, and Danica R. Robles..-

Bachelor's Thesis

College of Science..- Bachelor of Science in Environmental Science: Technological University of the Philippines, 2026.

Includes bibliographic references and index.

This study determined the presence and characteristics of microplastics (MPs) on
naturally occurring mosses in Intramuros, Manila during the wet and dry seasons. A
mixed-methods approach was employed, wherein the quantitative component utilized
observational biomonitoring to detect and characterize MPs, while the qualitative
component applied a descriptive survey design to identify possible sources contributing
to microplastic presence in the area. The research was conducted in three stratified
sampling sites in Intramuros, selected based on moss abundance and their representation
of different environmental conditions. Air quality was measured in terms of:
temperature, relative humidity, moisture, heat index, and wind speed. Microplastic
particles were characterized based on abundance, size, shape, color, and polymer type,
validated through Fourier Transform Infrared (FTIR) spectroscopy. A total of 36 out of
284 microparticles were confirmed as microplastics from moss and air samples across
both seasons. Fibers/lines were the dominant shape, and polyethylene terephthalate (PET)
was the most abundant polymer. Color distribution in moss samples was dominated by
white and transparent particles (wet season), and black particles (dry season). Larger
particles (2.37–5 mm) were most prevalent. Although higher abundance was observed in
the wet season, no significant difference was found between seasons (U = 3.00, p =
0.700), indicating that microplastic distribution is influenced by multiple interacting
meteorological and anthropogenic factors rather than seasonality alone. Findings confirm
that mosses function as passive biomonitors of MPs. It is recommended to expand
sampling coverage, develop standardized analytical methods, waste management policies
and public awareness, regarding possible health risk implications, and conduct long-term
multi-seasonal studies.

Keywords: anthropogenic activities, Intramuros, microplastics, moss, dry and wet season