Radiation, Air Quality, Weather Monitoring and Pollutant Source Regions

The RM-60 Micro-Roentgen radiation monitor by Aware Electronics (no longer available) has been set up (~2004) to provide real-time background radiation levels. The RM-60 is located on the south side of the building in a window frame, inside of the screen, but exposed to the outside air. Indoor background levels are normal and therefore only gamma (and perhaps beta) radiation is expected to be detected from outside sources. The RM-60 unit is monitored through the serial port using a LINUX program developed by Rickard E. Faith, which saves the count every two minutes and averages it over 15 minute intervals. Through 18 UTC 27 October 2019 monitoring was through the /dev/ttyS0 port and was then switched to /dev/ttyUSB0. The current counts through the USB port are twice as large as the previous ones through the COM serial port. The cause for the difference has not been determined. Display units are micro-R per hour. The long-term radiation data archive can be accessed by entering the end time of the desired six hour segment. Although data collection started 19 February 2007, online access is only available from 1 January 2020.

The Davis Vantage Vue, located about 5 m from the west side of the building on a 2 m pole over a grassy area, measures rain, wind, temperature, and humidity in a self-contained sensor suite. The sensors and transmitter are solar-powered with a battery backup. A passive radiation shield provides for more accurate temperature and humidity readings. The weather data updates every 2.5 seconds wirelessly to the WeatherLink Live receiver, which also contains a barometer, and inside temperature and humidity sensors. The data then uploads every 15 min to WeatherLink.com, Weather Underground, and the CWOP network via Wi-Fi. More information about the Vantage View is available from the Davis web site. The measurements are saved locally every two minutes. The wind speed and direction are the maximum and average values, respectively, over the last 10 minutes, while temperature and dew point are the instantaneous values. Precipitation is shown as an hourly rate every two minutes. Uploads to the web server occur at less frequent intervals. The long-term meteorology data archive can be accessed by entering the end time of the six hour segment. Although data collection started 15 August 2019, online access is only available from 1 January 2020. A graphical summary of the meteorology can also be created for each six hour period or for the period from the last cycle to the current time.

The PurpleAir PA-II uses a laser particle counter (PMS5003, PMS1003) to provide real-time measurements of PM1.0, PM2.5 and PM10. The PA-II is located 2 m from the west side of the building about 1 m above ground. The sensors count suspended particles in sizes of 0.3, 0.5, 1.0, 2.5, 5.0, and 10 µm and then use an algorithm to estimate the PM concentrations in µg/m3. The PurpleAir web site contains more detailed technical information about the sampler as well as links to map showing nearby locations deploying PurpleAir sensors. The measurements are averaged and saved every two minutes. Uploads to the web server occur at less frequent intervals. The long-term air quality data archive can be accessed by the end time of each six hour segment starting 4 May 2020.

Values from all three observational systems under the current conditions column are updated on the web server every 15 minutes. The archived radiation, meteorological, and air quality data are not available on-line prior to 1 January 2020.