The Department of Homeland Security (DHS) Science and Technology Directorate (S&T) released a draft Environmental Assessment for public comment on the use of safe tracer particles and non-toxic, inert, odorless gas as part of a scientific study on aerosol particle behavior in New York City.
The purpose of this study is to gather data on the behavior of aerosolized particles in a complex urban environment, including concentrations both in the air and deposited on environmental surfaces. Tests are planned to occur periodically between September 2021 and May 2022. These tests will be conducted at several street-level and transit locations in Manhattan that include Times Square, the World Trade Center complex, Union Square, and Grand Central Station. The tests will use only inert gas and particle tracers and pose no risk to the general public.
“This study is part of the Department’s ongoing commitment to public safety against the intentional or accidental release of substances that are harmful to human health,” said DHS S&T Program Manager Dr. Donald Bansleben. “We’ll be studying particulate transport between aboveground and underground environments, impacts associated with human movement, and sampling how particles may travel into neighboring boroughs and other locations that include transportation hubs and critical infrastructure. We’ll also be evaluating chemical and biological sensor technologies in the subway environment.”
The study will be conducted by researchers from a federally-funded research and development center and several government laboratories, and will use perfluorocarbon gas tracers, which are harmless, non-toxic, inert gases that have been used in dispersion experiments since the 1960s. Inert particle tracers consisting of the simple sugar maltodextrin and silica will also be used. These tracers are tagged with synthetic, non-infectious DNA, as well as a safe optical brightener commonly used in laundry detergents and paper manufacturing. These non-biological materials will allow particle tracer detection at very low concentrations.
The draft Environmental Assessment on the use of these materials has been posted on the DHS web site: http://www.dhs.gov/national-environmental-policy-ac and comments may be submitted until September 17, 2021, to: firstname.lastname@example.org.