August 21, 2026 

The Air Resources Laboratory (ARL) was founded in 1948 and is the oldest of the 10 labs in NOAA’s Office of Atmospheric and Oceanic Research. Over the decades, the lab has participated in numerous projects focusing on a range of atmospheric conditions. In some cases, ARL played a key role in establishing new networks; in other cases it operated specialized branches of larger monitoring efforts or collaborated with partner organizations to improve atmospheric research. While many of these networks have since been transferred to other organizations or retired, they reflect ARL’s long history of scientific collaboration and innovation. This article looks back at several monitoring networks that ARL helped create, support or operate, and the lasting contributions they made to atmospheric science.

AIRMoN and AMNet

The National Atmospheric Deposition Program (NADP) is a cooperative program made up of atmospheric monitoring networks with the purpose of collecting and evaluating air quality data. NADP is a coalition operated by a consortium of federal agencies, state governments, universities and private entities. Working together, these networks drive data-informed action to protect human health and preserve ecosystems. ARL collaborated with NADP on two networks, AIRMoN and AMNet. 

The Atmospheric Integrated Research Monitoring Network (AIRMoN) was established by ARL to monitor chemicals carried and released by precipitation. During the 1980s and 1990s, acid rain was a major environmental concern. Data was needed to understand where pollutants were coming from and how they were transported. AIRMoN served as a specialized branch of NADP’s National Trends Network (NTN) to help monitor precipitation. The NTN operated more than 180 monitoring sites across the United States that collected precipitation samples once a week to track long-term trends in acid rain. AIRMoN consisted of about 20 sites but collected samples daily. Daily sampling made it possible for the scientists to connect individual storms with the pollutants they carried, revealing where they came from and how they moved through the atmosphere. At the end of AIRMON in 2019, ARL’s towers were transferred to the NTN and converted to once a week sampling at that time.

The Atmospheric Mercury Network (AMNet) was established in 2007–2008 to monitor atmospheric mercury with the goal of determining where it travels and settles. Mercury is a toxic pollutant that can harm people and wildlife. When it is released into the atmosphere, it is absorbed into the rain cycle and ends up deposited on the Earth’s surface when it rains. The network is made up of monitoring sites that collect precipitation to measure mercury concentration. At its peak, around 2009–2010, AMNet operated 25 monitoring stations across the United States. ARL operated three of those sites, located in Beltsville, Maryland, Mauna Loa, Hawaii and Barrow, Alaska. The data collected by AMNet helped show that atmospheric mercury levels were decreasing after stricter regulations were placed on coal-fired power plants and other industrial sources. By documenting how mercury moves from the atmosphere into rivers, lakes and fish, AMNet provided important information used for protecting public health.

SURFRAD

The Surface Radiation Budget Network (SURFRAD) began in 1993 with the support of NOAA’s Office of Global Programs to provide accurate long-term radiation measurements. SURFRAD began collecting data in 1995 with four stations and expanded to six stations by 1998. During SURFRAD’s early years ARL played a central role in organizing and operating the network. It was created to understand how much solar energy reaches the Earth’s surface and how much is reflected back. Stations were strategically placed around the U.S. to continuously measure solar and infrared radiation, as well as meteorological variables such as ultraviolet radiation, aerosols, and cloud conditions so researchers can better understand the context of Earth’s energy budget. This balance is fundamental to understanding how heat is stored at Earth’s surface, helping scientists better predict and explain weather patterns. The network is now led by NOAA’s Global Monitoring Laboratory.

RAMAN

The Regional Atmospheric Measurement and Analytical Network (RAMAN) monitored meteorological and air quality conditions across the complex terrain surrounding Oak Ridge, Tennessee. It was established as part of an emergency response research program focused on detecting and tracking toxic chemicals. To prepare for a potential hazardous release, the network studied how winds move through mountainous deciduous forests. Because this type of forest covers much of the eastern United States, it provided a good setting for understanding how dangerous chemicals might move. The network was managed by ARL’s Atmospheric Turbulence and Diffusion Division, with a focus on collecting surface meteorological data, air quality measurements and ozone observations. By 2001, RAMAN included 15 ozone monitors deployed across its stations.The network provided data from different terrain by placing monitoring sites located on mountaintops, ridge-tops and valley floors. These locations allowed scientists to study how terrain, elevation and nearby urban areas influenced atmospheric conditions and regional air quality. ARL was the only lab operating RAMAN until it was retired in 2007. 

Although these monitoring networks have been retired or transitioned to other organizations, their scientific contributions still influence atmospheric science today and provide historical data crucial for understanding modern trends. They highlight ARL’s long history of innovative monitoring programs and advancing emergency preparedness, public health and ecosystem protection.