Air pollution and concern about air quality is not something new. Complaints were recorded even in the 13th century when coal was first used for industrial purposes in London. From the middle of the 19th century, the atmosphere of major British cities was regularly polluted by coal smoke in winters, giving rise to the infamous mixture of fog and smoke known as smog. Today the emphasis has shifted from pollution problems caused by the industry to the ones associated with motor vehicle emissions.
Air Quality Index
Air Quality Index, or AQI, is a number used by government agencies to communicate to the public how polluted the air currently is, or how polluted it is likely to become. As AQI increases, an increasingly large percentage of the population experiences severe adverse health effects.
Different countries have their own air quality indices corresponding to different national air quality standards. Some of these are Air Quality Health Index (Canada), Air Pollution Index (Malaysia) and Pollutant Standards Index (Singapore).
The national AQI was launched in New Delhi on September 17, 2014, under Swachh Bharat Abhiyan. There are six AQI categories (Table I) of the same. The proposed AQI considers eight pollutants (PM10, PM2.5, NO2, SO2, CO, O3, NH3 and Pb) for which short-term (up to 24-hour averaging period) National Ambient Air Quality Standards are prescribed.
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In this project the sensors used are SDS011, MQ-135, DHT11 and DS1307 (as shown in Fig. 1).
A typical PM2.5/10 air quality meter costs around US$ 200. Here we present an air quality meter for monitoring air particles, gas concentration, temperature, humidity and time, which costs around US$ 45 only. Block diagram of the air quality meter is shown in Fig. 1.