The VOC number on the CAMP dashboard is a reading of total Volatile Organic Compounds measured by a photoionization detector (PID) with a 10.6 eV lamp. The PID detects may different VOCs but cannot tell them apart. Because some VOCs cause the PID to have a stronger response than others, the readings produced by this sensor are intended to provide a qualitative indication of the presence of VOC. A year to date average for each site is provided to give context to the current day’s average displayed on the dashboard.
VOCs or Volatile Organic Compounds are chemicals that contain carbon and react in the atmosphere to form ozone.
PM is the mixture of extremely small solid particles and liquid droplets suspended in the air (dust, dirt, soot, or smoke, ash, metals and allergens), and other various solid and liquid hazardous chemicals found in the atmosphere.
Particulate Matter is classified according to size. PM2.5 are “Fine inhalable particles,” that are 2.5 microns in diameter and smaller. PM1 are “Ultra-fine inhalable particles,” that are 1 micron in diameter and smaller. PM10 are "Inhalable coarse particles," that are 10 microns in diameter and smaller. PM2.5 and PM1 are of greatest concern to human health. They can get deep into the lungs and enter the bloodstream where they may cause adverse health effects. Larger particles are of less concern as they tend to collect in the upper portion of the respiratory system.
The monitors are designed to trigger a sample canister when they detect high levels of VOC. The canisters can then be collected and taken to a lab for analysis. PCS is currently developing criteria for sample collection and is testing canister samples at 4 CAMP sites. Eventually, all the CAMP VOC monitoring sites will be equipped with these canisters.
PCS plans to post cannister sample results on the PCS website. Currently, canister sample data from the four canister sample test locations are available on request.
The VOC monitors at John Phelps and North Channel Library are provided by a different manufacturer than at PCS’ other monitoring sites. The factory calibration of these two monitors produces higher baseline readings than our other sites. PCS will normalize the readings between the two different models of VOC monitor in an upcoming round of calibrations.
PCS will periodically remove data that is not valid because it was collected during monitor maintenance or is the result of malfunction.