As of the 10th of November 2016 the Now-Cast measurement in Kuala Lumpur, Malaysia by The Safety Educator has been taken off-line and put on HOLD due to increasing operating costs. The Safety Educator intends to modify the setup and have it back online before end 2017. If you would like to assist The Safety Educator in keeping this important resource running please contact us.

It is important to note that this is a measurement from a consumer-level monitor, and will not be as accurate as an industrial-level monitor. It should be seen as a guide only, see our Methodology description below for more information.

Use the below table to determine if the AQI measurement is healthy or not (from Living with Air Pollution): SeeTo see a continuously updated PM2.5 outdoors KL AQI on your smartphone you can:

• Follow us on Twitter @KualaLumpurAir (updated every 60 minutes).
• Download the Speck Sensor app on Android, or iTunes, then select Kuala Lumpur.
• Install a Weather Underground app on Android, or iTunes, and link to the Personal Weather Station for The Safety Educator, called IFEDERAL6. Now-Cast AQI is shown under solar radiation.

For a graph of all raw data measured from the unit (particle concentration and temperature, but not AQI) please see this link (opens in a new page). To lower AQI indoors please use a True-HEPA air purifier.

Methodology

As parents  in The Safety Educator we have been disheartened of the very poor air quality in the ASEAN region recently (October 2015), particularly in Indonesia, Malaysia and Singapore. As per our recent article on Living with Air Pollution, one of the most essential measurements of air quality is PM2.5 (solid particles in the air smaller than 2.5 microns), unfortunately the following countries do not yet measure this important safety data to it’s citizens – Malaysia, Thailand and Brunei. As The Safety Educator is partly based in Kuala Lumpur we decided to investigate ways in which we could measure and provide our own PM2.5 measurements to the population, similar to what the US Embassy did in Beijing. This will give concerned citizens a more accurate representation of the quality of the air at any given time.

Finding a Monitor

In looking for a PM2.5 monitor we had a few requirements:

• Reasonably priced – not an industrial unit like the Met One BAM-1020, or the Ecotech EC9810, both of which can cost as much as a small car,
• Accurate,
• Minimal maintenance,
• Able to upload data to the internet on a continuous basis.

Our review turned up many potential solutions, but it became quickly clear that the best technology within our requirement would be an optical or laser style measurement system. The main options we could find were the:

• Dylos DC110o Air Quality Monitor – This looked excellent, it has a long history of use, good quality, and simple measurement. However it could not easily be connected to the internet for continuous updating.
• Foobot – This unit measures PM2.5 but it appears to not use any fan to ensure consistent flow through the unit to provide accurate readings, so we decided against it.
• CubeSensor – This unit had limited technical information on the particle measurement itself so again we decided against it.
• Speck – This unit is from an off-shoot company from Carnegie Mellon University. It only measures Pm2.5, does it accurately and uploads constantly to the internet. It also uses a fan to obtain samples, and uses machine learning to improve accuracy and individually calibrate each unit.
• Other units (Netatmo, AirQualityEgg, etc) measured many other important air values, but not PM2.5.
• There were many Kickstarter (TZOA, Air.Air!, Koto, etc)  and Indiegogo (WEPO, Birdi, Air Monitor, etc) units ‘coming soon’ however we needed something quickly and could not wait.

So in the end we decided to purchase one Speck unit for outdoors and got it delivered to Kuala Lumpur.

Installation

We wanted to make sure we got the most accurate measurements possible, so we did some searching and found an excellent report by the US EPA detailing testing they have conducted on low cost PM2.5 units (unfortunately the Speck results were not obtained as the unit broke). Along with this we also found a budding online group at Public Lab, outlining very cheap ways of obtaining accurate measurements (e.g. DustDuino), however The Safety Educator did not have the technical skills to replicate these systems. From our searches we found the following recommendations about outside installation (in particular as ALL consumer units are specified for indoors only):

• With optical measurement systems direct sunlight will give a false reading, so the units must be fully covered.
• However they also need good air flow, in an area where the air is in movement so as to obtain a representative sample of the air with multiple measurements over an hour (in this case we measure every 3 minutes, so 20 measurements per hour).
• The air inlet must be open and have flowing air available for testing.
• It cannot get wet.
• High humidity (greater then 90%) does impact the measurement (giving a higher value then reality). Unfortunately at our price range there is nothing we could do about this.

From the US EPA report they recommended a very technically named “Bowl on Pole enclosure”, as seen below. We replicated this with an old speaker stand, board with drilled holes, and kitchen stainless steel bowl, as seen below. This is located in an outdoor elevated (1m from ground) undercover position.

Photos showing the installed outdoor Speck. The left shows the Speck (on a good day) with the lid off. The right photo show underneath the Speck, the suction vent next to the USB power cable, the steel cover over the Speck and the black part on the right is the speaker stand elevating the unit by 1m.

We think this is the best we can do with the tools we had available, and should give the most accurate measurement possible.

AQI Calculation

The Speck data is stored on the internet and accessible via calling an API (Application Program Interface). The basic calculation methodology can be seen below:

• We use Runscope to  call the raw measured PM2.5 particulate values (in μg/m³) from the Speck storage repository every 5 minutes (which is part of the Carnegie Mellon ESDR).
• The Safety Educator has set a JavaScript program at Runscope which then calculates the US EPA Now-Cast AQI, Instant-Cast AQI and Category level. These calculations are as per recommended guidelines, with the revised PM2.5 breakpoints as confirmed via US EPA Standards Updates. Now-Cast is calculated as per the US EPA Guidelines. For further information see the excellent overview from AQICN.
• Runscope then sends the calculated values back to the ESDR repository.
• The Safety Educator then calls the ESDR repository every minute to make sure the latest figure is being shown on the page.
• Runscope also sends the results to our Twitter account (@KualaLumpurAir) every hour, and to our Weather Underground Personal Weather Station every hour..

A summary of the calculation can be seen in the formal document developed by The Safety Educator as seen below. You are welcome to review and use as you need. It is important to note that our calculations only take PM2.5 into account, we do not measure the 5 other pollutants used in AQI calculations, namely PM10, Ozone, Nitrogen Dioxide, Sulfur Dioxide and Carbon Monoxide. The way the AQI works, based on US EPA information, is that each pollutant has it’s own AQI calculated, and then the largest AQI ONLY is used to show the overall AQI. Each pollutant AQI is NOT summed together. The Safety Educator AQI is for PM2.5 only, so other pollutants may have a higher AQI value, we will investigate further on adding other pollutants to our calculations. Thanks to Chris Bartley at Carnegie Mellon University and Audrey at Runscope for their assistance in setting this up.