Air Quality Information

Introduction

I have added an air quality monitor to my weather station (see below). The sensor I am using is the Plantower PMS5003 sensor and I have used a Raspberry Pi to capture and process the data and upload xml files to the internet to display the recorded data on my website. The software is based on that produced by https://www.rigacci.org but I have adapted it to display current and historical information on my website. I am also uploading the information to Weather Underground (Wunderground), although at present, Wunderground does not seem to display this data nor make it available for historical analysis.

Information Recorded

The information I am recording is 'Particulate Matter' PM1.0, PM2.5 and PM10. These are particles with a diameter of 1.0μm or less, 1.0μm to 2.5μm and 2.5μm to 10μm respectively. The latter two are measured for air quality monitoring. The differences between these are as follows:

PM2.5 - These are referred to as fine particles. They are commonly found in smoke and haze. They can penetrate into the lungs. Studies have shown that exposure to high levels can lead to respiratory and cardiovascular problems especially in vulnerable groups.
PM10 - These are coarse particles. These generally come from vehicles on dirt roads and dusty industries such as mining, crushing and grinding. The particles can also lead to respiratory problems, as well as irritation to eyes and the throat.

The measurements recorded are in μg/m³. On my website I give the current reading and the highest reading recorded during the day. Additionally, I calculate the Air Quality Index (AQI) for each type of particle. Around the world different methods are used for defining AQI; I use that defined by Environment NSW. Note that the AQI measurements record the mass of particles below 2.5μm and below 10μm respectively. Therefore for the PM2.5 AQI reading I am including the readings for 1.0μm and 2.5μm; for the PM10 AQI I am including all 3 readings.

Safe Levels

Different states and countries set different thresholds for acceptable levels of the particulates. In NSW, the safe levels are as follows:

	PM2.5	PM10
24 hour average	25 μg/m³	50 μg/m³
Annual average	8 μg/m³	25 μg/m³

The AQI is calculated using the 24 hour average value equating to an AQI of 100. The following table, again from Environment NSW defines the action to be taken depending on the recorded AQI.

The Air Monitor

Here is the air quality sensor I used - the PMS5003. These are readily available on eBay for about $30.
I used a Raspberry Pi in a weatherproof housing (from Jaycar electronics - but available from many suppliers) to connect to the sensor and transmit the information via WiFi. I bought a rain cowl from Bunnings to go over the air sensor but still allow the air to be measured (see image on the main page).

Links

For further information, the following links may be useful:

http://www.environment.nsw.gov.au/AQMS/aqi.htm

https://en.wikipedia.org/wiki/Particulates

http://www.epa.vic.gov.au/your-environment/air

https://www.epa.gov/pm-pollution/particulate-matter-pm-basics

If you have any comments, or want any information, please send me an email at steve@tijou.co.uk.

This page was last updated 5 February 2018.

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