NOAA’s Air Resources Car (NOAA’s ARC)

NOAA’s Air Resources Car, NOAA’s ARC, is a mobile platform using a modified sport utility vehicle to find and measure sources of greenhouse gases (GHGs) and air pollutants, particularly in urban environments. NOAA’s Air Resources Laboratory uses the ARC to conduct routine measurements in the Baltimore Washington region and up through the Northeast Corridor.


The Instrumentation

The ARC is one of several platforms that ARL uses to detect greenhouse gases and other air pollutants. ARL’s other platforms include two surface installations and a Cessna 402 research aircraft outfitted with instrumentation similar to that on the ARC. Using multiple installations serves  several purposes: to verify another platform’s data, and to cover larger areas. The ground stations also provide longer term data, as they operate 24/7 and through all seasons, weather, and changing traffic patterns in the DC metro region.


The need to monitor urban greenhouse gases

In the US, almost 70% of the greenhouse gas emissions that are human caused – also called anthropogenic – are from urban areas. In order to meet the US climate emissions target goals, urban leaders have been making commitments to reduce GHGs. One initial step is to determine emissions and sources of greenhouse gases in urban areas. The ARC has been driven extensively through Baltimore, MD and Washington, DC and has located numerous neighborhoods with anomalously high pollution concentrations and urban heat island effects. Many of these involve disadvantaged communities where the populace are particularly vulnerable to environmental pollutants. The platform is also useful to identify major point emission sources of greenhouse gases such as landfills, wastewater treatment plants, and natural gas compression stations. These hyperlocal measurements of greenhouse gases and air pollutants can help to address environmental justice issues.


Intended outcomes and goals

Quantification of urban GHG emissions is a necessary first step to help meet the targeted GHG emissions goals. The ARC is useful to provide informed science to policy makers in the DC metro area and the eastern US. By measuring emissions in local regions, researchers can inform of sources that are not obvious or are intermittent; for example: natural gas pipe leaks. Researchers can also evaluate the accuracy of existing emissions inventories and investigate long term trends of greenhouse gases and their drivers. The overall goal is to provide policy relevant science to mitigate the emission of greenhouse gases and air pollutants and their impacts on climate change and air quality.

The Air Resources Car performing measurements while on a ferry.
The Air Resources Car and the UMD Cessna prepare for field experiments on July 28, 2023. Using data from both platforms provides more information on the sources of greenhouse gases and ozone on a regional scale. Image Credit: NOAA ARL.
Driving in NYC traffic helps determine where pollutants originate. Here, the Air Resources Car waits at a red light in Brooklyn while taking measurements.
Xinrong Ren calibrates instruments onboard the NOAA ARC that measure greenhouse gases (methane, ethane, Carbon Dioxide, Carbon monoxide); pollutants such as Black Carbon, Ozone and nitrogen oxides; and meteorology, including, wind speed, direction, temperature, relative humidity, and pressure. Image Credit: NOAA

ARC measures variables such as:

  • Methane: CH4
  • Ethane: C2H6
  • Carbon Dioxide: CO2
  • Carbon monoxide: CO
  • Black Carbon
  • Ozone: O3
  • Nitrogen oxides: NOx

ARC Science Campaigns:

  • DC-Baltimore surveys (spring/fall 2022)
  • Marcellus Survey (fall 2022)
  • AEROMMA (summer 2023)
  • Denver-Julesburg Basin survey (fall 2023)
  • Utah Summer Ozone Study (summer 2024)
  • DC-Baltimore surveys (summer 2025)