Methane

Methane (CH4) is the second most important greenhouse gas after carbon dioxide (CO2), and a precursor to surface ozone formation. CH4 has 80 times greater Global Warming Potential (GWP) than CO2 over a 20-year period, and a shorter lifetime. Reducing methane emissions is considered one of the most cost-effective ways to slow down near-term global warming. In urban areas, CH4 is mainly emitted from natural gas systems, landfills, and sewers.

Methane Emissions from New York City Metro Area (NYCMA)

New York City (NYC) is among the top 100 persistent methane sources globally and is the largest methane emitter in the Northeast US. Current national and regional methane inventories are consistently underestimating NYCMA mathane emissions. We use tower-based, rooftop, mobile platform, and drone measurements to quantify both city-scale and source-specific methane emissions from NYCMA. Schiferl et al. (2025) used long-term rooftop measurements in the NYCMA city core to show that wintertime NYCMA methane emissions are correlated with incomplete combustion signals.

Urban Methane Sources

Natural Gas

Natural gas (NG) sector is a significant methane source, contributing to 30% to 42% of anthropogenic methane emissions globally. Methane emissions from the natural gas sector in New York City can be underestimated by up to 10 times based on previous airborne observations. Currently, we are using tower-based observations (1Hz) of ethane, methane, and carbon monoxide in NYC to attribute methane emissions from pre- and post-meter NG sectors during winter and summer as part of the FROG-NY and FROGSICLE Campaign. 

Landfills 

Landfills account for 20% of global methane emissions. We developed a method to estimate methane emissions using the Rutgers tower site, benchmarked against mobile measurements, and aircraft data. Over two and a half years, our measurements revealed a strong seasonality at a New Jersey landfill, with the peak of emissions in early winter. Emissions were highest when temperatures were around freezing and atmospheric pressure was rapidly decreasing.

Waste Water Treatment Plants (WWTP)

Wastewater treatment plants emit significant amounts of methane. We are working on monitoring methane emissions from a nearby WWTP using an eddy flux system in an attempt to identify and reduce emission sites.