We use Atmos (low-cost sensor-based) monitors for real-time monitoring of the solid particles (Particulate Matter (PM)) such as PM1, PM2.5 and PM10. It also provides ambient temperature and relative humidity data. Data is transmitted to a cloud server on a real-time basis using a built-in WiFi module and has a battery backup for up to 8 hours. The device also has an internal MicroSD card in which the data get stored as well. The devices are scientifically validated Federal Equivalent Method (FEM) grade equipment with linear regression under different conditions has varied from 0.7 to 0.9.
In the city of Chennai, Atmos monitors are located in 7 sites in collaboration with healthcare infrastructures and community members. This collaborative model helped us in disseminating the data along with health education.
The real-time readings of PM1, PM2.5 and PM10 can be viewed on the dashboard here.
In addition to real-time air quality monitoring, we conduct annual rounds of 24-hours low volume air sampling exercises in the city of Chennai MiniVol portable sampler. This device is used for measuring PM10 and PM2.5 along with heavy metals in the ambient air. The device can be programmed for 24 hours and is a pump controlled device that draws in the air by suction. The drawn air passes through particle size separators and gets adsorbed on the Teflon filter placed in the device. The flow meter is set at the rate of 5 litres per minute in order to mimic a healthy human lung capacity. The filters are then sent to a laboratory for analysis.
Bucket Brigade: For measuring the Volatile Organic Compounds (VOCs) and Sulphur compounds present in the ambient air, community activists in the United States (US) have developed a well-tested tool called the “bucket”. The plastic bucket serves as a rugged enclosure for a standard “Tedlar” sampling bag. Ambient air is sucked into the bag using small vacuum suction. The sampling bag is then removed and sent to the US Environmental Protection Agency (EPA) accredited laboratories for analysis. This technique cannot test for Particulate Matter (PM) or radiations. The bucket deploys the same technique as the USEPA and the industries. This technique was co-developed as a community tool by the US EPA. Bucket samples detect VOCs and Sulphur compounds at parts per billion (ppb) levels.