1. What do I need to monitor air pollution with a portable monitor?

There are many different types of outdoor air pollution. Measuring them all would be too expensive, so regulators focus on a smaller group of common air pollutants, sometimes known as the criteria pollutants. The criteria pollutants are:

  • Nitrogen dioxide (NO2)
  • Sulfur dioxide (SO2)
  • Carbon monoxide (CO)
  • Ozone (O3)
  • Particulate matter (PM)

As always requirements should be confirmed with your local regulatory body.

2. What is a sensor head?

Sensors are housed within an interchangeable ‘sensor head’ that attaches to the monitor base. You can choose from up to 28 different gas and particulate sensor heads. Each sensor head contains a single gas or particle sensor. Swapping sensor heads takes seconds and no configuration or re-calibration is required.

Portable air quality monitor sensor options

3. How accurate is my sensor head?

You can find our specifications for our sensor heads here:


Note: Accuracy may drift as the sensor ages.

4. How long do the sensor heads last?

Aeroqual recommends replacement after two years, however higher exposure levels or harsh environments can lead to a significant reduction in life expectancy. Your monitor display is likely to indicate Sensor Failure or Sensor Ageing if the sensor is nearing the end of its useful life.

Note: Sensor heads may degrade even when unused and in storage.

5. How many sensors can I use on the monitor at once?

You can only connect one gas or particulate sensor head at a time to monitor. However, you are able to connect the optional temperature and humidity sensor at the same time as a gas or particulate sensor head.

6. Can I use the PM sensor head with any portable monitor?

The PM sensor is compatible with Series 200/300/500 monitors with software version 6.4 introduced in November 2014.

7. Why does my Ozone sensor head take a long time, or fail to, "warm-up"?

VOC presence in the sample is the most common cause of longer warm up times. VOCs are often present in indoor areas released from carpets, paints, clothing etc.

Taking the monitor with ozone sensor head outside or opening a window and having the sensor sample outdoor air should speed up the warm up cycle.

8. Why will my instrument only function when connected to a power supply?

The Battery may have become disconnected. Please check the connection under the battery:

battery connection check portable monitor

9. Which battery do I need?

Aeroqual portable monitors ship with a Lithium (Li) battery. Older models may have a nickel metal hydride (NiMH) battery. Batteries are not cross-compatible (you cannot use a lithium battery in a unit that currently has a Nickel battery).

The easiest way to tell is by the colour of the battery back. Lithium batteries are blue and Nickel batteries are green.

  • Lithium battery = part number “AS R36”
  • Nickel battery = part number “AS R31”

Note: Lithium batteries cannot be shipped internationally on their own.

10. How do I know that the battery is charging?

Lithium Smart Charger LED Status:

  • Red LED = Battery is charging, OR battery is fully charged, and monitor is on.
  • Green LED = Battery is fully charged, and monitor is off.

Nickel Battery Charger:

  • The battery icon on the display flashes.

11. What is the PPM to mg/m³ conversion factor?

PPM is an absolute measurement, whilst mg/m3 varies depending upon pressure and temperature. The portable monitor measures in PPM and applies a conversion factor if you wish to measure in mg/m3.

Sensor PPM conversion to mg/m3
NH3 0.76
CO 1.25
CO2 1.96
CL2 3.16
CH2O 1.34
H2 0.082
CH4 0.72
H2S 1.52
NO2 2.05
NMHC 2.5
O3 2.14
C2CL4 6.78
SO2 2.86
VOC 2.5

*as particulate matter varies in size, unlike a gas molecule, PPM is not a valid unit of measurement

12. Can I change the conversion factor?

No, the conversion factor cannot be changed on the sensor head or with the S500 PC software. To apply a different conversion factor, log your data in PPM and calculate the mg/m3 readings via data export from the Series 500 PC software to third party software (eg. Excel Formula).

You can download the Series 500 PC software here.

13. Do I return the instrument for calibration?

Only the sensor head needs to be calibrated. The base unit does not need to be calibrated. All parameters are stored on the sensor head.

The sensor head calibration should be completed after the first year. Aeroqual does not recommend a second factory calibration, but rather replacement after two years of operation.

See a range of frequently asked questions on calibration here.

14. Why can’t I select “calibrate” in the menu?

To ensure settings are not changed accidentally, to enter the calibration menu you must hold down the mute and down arrow buttons for 2 seconds rather than use the enter button.

15. How do I start logging on the handset (Series 500 only)?

  1. Select Monitor Setup then Logging Setup
  2. Set the Logging Frequency using the up/down arrows and press Enter
  3. Select to Clear Existing Logged Data or Not and press Enter
  4. Select On under Logging and press Enter


  • Data logging can be both started and stopped directly from the main display screen by pressing the scroll up button for 2 seconds until the monitor beeps (if the monitor keys are not muted).
  • The data log can also be cleared directly from the main display screen by holding down the mute button for 2 seconds until the monitor beeps (if the monitor keys are not muted).

16. How do I know that the instrument is logging data (Series 500 only)?

When data logging is initiated a triangle will appear on the main display screen. The triangle is an indication that data logging is active, and is also used as an indication of the presence of data, as below:

Empty data log An empty triangle indicates that no data is stored.

data logging active triangle indicator A filling triangle indicates that some data is stored in the memory. The triangle will fill up in 10% increments.

data log is full triangle indicator A full triangle indicates that the memory is full and needs downloaded to the PC.

17. How Long can I log data for (Series 500 only)?

The Series 500 handheld unit can store a limited number of data points (8188), meaning that the length of time that data can be logged depends upon the frequency and number of data points recorded. For example:

  • If you are logging every minute for one gas (i.e. one data point per minute) you can log for 8188 minutes.
  • If you are logging every minute for one gas, temperature and humidity (i.e. 3 data points per minute) you can log for 2729 minutes.

Decrease the logging frequency for the ability to log over a longer timeframe.

Note: Once capacity is reached new data will begin to overwrite the oldest logged data.

18. If I set a logging frequency greater than 1 minute is the logged data an average (series 500 only)?

It is a single sample taken at the point it is logged. No Averaging is performed.



Logging Frequency set to 1 Minute Logging Frequency set to 5 Minutes
Time Logged Reading Time Logged Reading
11:00 0.01ppm 11:00 0.01ppm
11:01 0.11ppm 11:01
11:02 0.15ppm 11:02
11:03 0.09ppm 11:03
11:04 0.05ppm 11:04
11:05 0.02ppm 11:05 0.02ppm

19. If I turn on the min/max/average setting are these values logged (Series 500 only)?

The only thing that is logged is the value for the individual samples taken. The max, min and average values are just displayed not recorded.

The general expectation with averaging is that you would simply log data every minute and then export the data to csv and calculate averages from the raw data.

20. What communication options does the portable monitor have?

S200: None

S300: 0-5V Analog output (current reading only)

S500: 0-5V Analog output (current reading only), RS232 (current, logged data and instrument control) to PC software via USB adapter. RS232 protocol available upon request for third party software integration.

21. Can I turn on PC data logging for multiple monitors at a time (Series 500 only)?

No, the software will only talk to one monitor at a time. This is not a network product. You may want to consider our Series 900 fixed monitor product which is designed for network applications.

22. How do I download the logged data from my Series 500 unit?

Video: Downloading data from your Aeroqual S500

1. Download the PC software and install onto your Windows PC: S500 PC Software Download

2. Turn on the Series 500 unit.

3. Connect the supplied RS232 to USB cable to the base unit and to your PC. The USB connector’s LED should flash on/off briefly.

4. Start the Series 500 software.

5. Select File -> Search for connected monitor. The S500 should beep and the software indicate a successful connection

6. Select File -> Download logged data. The data will be transferred to your PC and logging will be automatically turned off on the instrument. You can now view or export the data.

23. How can I put my logged data into an Excel spreadsheet (Series 500 only)?

You can save the data from the S500 PC software to a CSV file by choosing “Export Logged Data” under the file menu. You then need to specify the date range for the data you want to save and the monitor ID it has come from. When you select “Export” you will be prompted to select a location to save the file:


Series 500 data export example image

24. What units are my measurements in when viewed in the software / data export (Series 500 only)?

Units will always be what they were set to at the time of measurement. Note that current software version (6.5) data export will always show ppm as the title for the measurements column.

Units Set at time of Logging Units Set at time of Download Units Displayed in Software Units Displayed in .csv Download True Units
ppm ppm ppm ppm ppm
ppm mg/m3 mg/m3 ppm ppm
mg/m3 ppm ppm ppm mg/m3
mg/m3 mg/m3 mg/m3 ppm mg/m3

25. Why can’t I transfer logged data (Series 500 only)?

Ensure the instrument is powered on, it does not power by USB, otherwise please follow troubleshooting steps below:

1. Does the base unit indicate there is stored data by the black triangle at the bottom of the screen?

Yes – Continue to step 2.

No – There is no logged data. Ensure you enable logging on the base unit.

Note: Logging is stopped automatically when you download data to the PC and needs to be restarted after. Logging can be stopped and started by holding down the up arrow on the base unit for 2 seconds. Logged data may be accidentally cleared if you hold down the mute button for 2 seconds.

2. Does the internal LED in the USB cable flash when you connect it to the PC?

Yes – Continue to step 3.

No – Ensure you are using the cable supplied by Aeroqual. Try a different USB port or try a different cable.

3. Does the software detect that the monitor is connected when you search for connected monitor?

Yes – Continue to step 4.

No – Connect the USB cable to your PC (but not to the S500).

Open Windows Device Manager and expand Ports (COM & LPT). You should see the Com Port displayed as below:

USB serial port (COM6)

Now run the S500 software (still without the series 500 connected to the cable). Select Monitor and then Com Port.

Set the Com Port Setting to match what was displayed in device manager as below:

set com port
Note: if the port cannot be found within Windows Device Manager then you may need to install the FTDI driver. Refer to FAQ 26. How do I download drivers?

4. Does the progress bar indicate data is being transferred when you download data to PC?

Yes – When downloading data for the first time, the data is likely to be time stamped incorrectly unless you have set up the date in the monitor prior to logging. When displaying data choose to view data starting from a much earlier date (including the year). To ensure future data is time-stamped correctly enter monitor setup in the S500 software and select Update Clock.

update clock

No – There is no data, disconnect the instrument and start logging, wait 5 minutes and then download data to test if new data is correctly logged.

26. How do I download drivers?

The Aeroqual supplied USB cable converts the RS232 output to a USB input for your PC. This requires a driver to operate, usually this FTDI driver is packaged and installed with your Windows installation.

If for any reason you need to install drivers manually you can download the driver package here.

Note: Please discuss with your IT or Systems Administrator if you are unsure what you are doing.

27. Why do I get a JavaScript error or Windows error 2 when installing the PC Software?

You are using an older installer that is not compatible with newer versions of JavaScript on your PC. Install software version 6.5 or higher.

The latest software is available here.

28. Can I use the PM sensor head with the S500 PC Software?

Yes, but you must be using software version 6.5 or higher. The latest software is available here.

29. Can I convert measurement units within the S500 PC software?

No, the units option exists only so you can set the units displayed in the software to match the units you logged on the instrument. If you set the units in the software incorrectly then the displayed data is not converted, and the data is incorrect.

30. What is the “Control” function (Series 300 & 500 only)?

This is designed to control generation of a gas such as ozone from an ozone generator. The control pin can be wired to control a gas concentration between upper and lower concentration limits. The upper and lower limits can be set by the user via this control function.

Refer to the relevant section of the user guide for wiring instructions.

31. What does "P" beside the symbol for muted alarm mean?

The “P” stands for “permanent”, when the alarm buzzer has been disabled in the alarm menu, this means the alarm is permanently muted.

This is to differentiate between pressing the mute button on the display panel, as that only mutes the current alarm condition. Once the alarm condition is reset the muting is disabled, if there is a subsequent alarm the buzzer will sound.

32. I have two monitors side by side why are they giving different readings?

Ensure there are no gain factors or offsets in use on either instrument. Individual sensor heads may vary in their readings for many factors, both environmental and related to the sensors themselves.

Calibration and age is an important factor. Over time, and with use, the calibration drifts. Sensor heads should be regularly tested and calibrated to ensure their correct operation. Calibration conditions such as humidity will also affect readings if non-factory calibrations are performed. Sensor heads have a clean stainless-steel mesh to filter out dusts. If this becomes dirty over time the sensor head will start to read incorrectly and will need to be replaced.

Target gases such as ozone are highly reactive. Ozone will rapidly react with organic compounds and surfaces such as walls, flooring, plastic testing chambers and people. Concentration gradients are common in rooms and are greatly influenced by air movement and mixing. Concentrations may be lower near walls and surfaces or in areas with low air flow

33. What accessories are available for the portable monitors?

Aeroqual offers a range of accessories to suit your application. See the range here.

34. Can I buy online?

Aeroqual does not sell online. If you have received a quotation from us and are ready to pay then you can pay by credit card online here.

If you want a quote then take a look at our product pages below, select the product you are interested in and request a quote.