What is BEACON?

BEACON is a new approach to observing atmospheric gases over an urban area. Instead of using a small number of extremely sensitive instruments to measure a large area, we blanket interesting locations with a high density network of instruments, with each instrument representing a network “node”. Individually, measurements from these nodes are of moderate quality, but when taken together as a network produce an accurate, highly resolved picture of real-time pollutant concentrations. Each node measures CO2, a major anthropogenic (human-influenced) contributor to climate change, and reports back to this site where the collected data including temperature, pressure, and relative humidity is publicly available for viewing and download. The nodes also collect data on nitrogen dioxide (NO2), ozone (O3), and carbon monoxide (CO) which are indicators for the overall air quality of an area, and may be useful for tracing the origins of CO2 emissions. These data are not yet ready for public viewing, but will be added to the site soon.

 

BEACON is also a novel approach to scientific outreach. A science curriculum for K-12 teachers using the BEACON sensors has been developed by scientists and educators at the Chabot Space and Science Center in Oakland, California. To the extent possible, nodes are being placed on the rooftops of local area schools, so that students may see for themselves the greenhouse gas (GHG) pollution in their area. We also have plans to place nodes on other local science museums, and will be working with staff to facilitate displays of the BEACON data. 

 

To get a feel for the potential variability of CO2 over the California Bay Area, we have simulated the concentrations over the area for a two-week period and compiled them into this movie. You can see high concentrations around the cities, building up during the day (when there are cars on the road) then dispersing overnight.

The BEACON Instrumentation

Each BEACON site hosts a single "node" for the network. These nodes contain sensors for CO2, NO2, O3, and CO, in addition to sensors for temperature, pressure, and relative humidity. Data from these sensors are collected once every five seconds onto a miniature computer which then sends the data to a centralized server. When combined with data from other nodes, it can be used to produce concentration maps, track pollution plumes, and to constrain calculations of emissions, to name a few possibilities. The data are also stored on-board the nodes; in the event of network failure, each node will store its collected data until connectivity is restored.

 

A BEACON node is contained in a stainless steel box, weighs approximately 25 pounds, and is the size of a backpack. In addition to the sensors and computer, each node contains a power converter to prevent surges, intake and exhaust fans to maintain an even airflow and prevent overheating, and a wi-fi adapter or long ethernet cable to send data to the central server. At this time, nodes require wall power (an outlet); later generations may use solar panels or other power sources.

 

 

When deployed, the nodes are placed on rooftops, mounted on poles or railing that raise the instruments several feet above the roof surface. Care is taken to ensure that the nodes are placed where they will sample free flowing air away from air handling units or building exhaust. In areas where theft or vandalism is a concern, the instruments are secured according to the advice of the building managers.