Plastic debris, including nanoplastic particles (NPPs),
has emerged
as an important global environmental issue due to its detrimental
effects on human health, ecosystems, and climate. Atmospheric processes
play an important role in the transportation and fate of plastic particles
in the environment. In this study, a high-resolution time-of-flight
aerosol mass spectrometer (HR-ToF-AMS) was employed to establish the
first online approach for identification and quantification of airborne
submicrometer polystyrene (PS) NPPs from laboratory-generated and
ambient aerosols. The fragmentation ion C8H8+ is identified as the major tracer ion for PS nanoplastic
particles, achieving an 1-h detection
limit of 4.96 ng/m3. Ambient PS NPPs measured
at an urban location in Texas are quantified to be 30 ± 20 ng/m3 by applying the AMS data with a constrained positive matrix
factorization (PMF) method using the multilinear engine (ME-2). Careful
analysis of ambient data reveals that atmospheric PS NPPs were enhanced
as air mass passed through a waste incinerator plant, suggesting that
incineration of waste may serve as a source of ambient NPPs. The online
quantification of NPPs achieved through this study can significantly
improve our understanding of the source, transport, fate, and climate
effects of atmospheric NPPs to mitigate this emerging global environmental
issue.