MODULAIR (pre-2025)dhh

1. Introduction and Specs

MODULAIR™ provides real-time estimates of particulate matter concentrations (PM1, PM2.5, PM10), the particle size distribution, and four gas-phase measurements. MODULAIR utilizes the same, patent-pending particle measurement technology found in the MODULAIR-PM, which combines nephelometry with single-particle scattering to accurately measure aerosol loadings across a variety of environments.

1.1. Specifications

1.1.1 Air Quality Measurements

*Temperature and relative humidity are measured inside the flow cell and should not be interpreted as true ambient measurements.

For more information on the operating principle and performance of the MODULAIR, please refer to , , and .

1.1.2 Power and Communications

1.1.3 Operating Specifications

1.2 Certifications

1.2.1 FCC 15(b)

The MODULAIR™ air quality sensor complies with part 15 of the FCC rules for class A devices. Operation is subject to the following two conditions: (1) this device may not cause harmful interference; (2) this device must accept any interference received, including interference that may cause undesired operation.

Model: MODULAIR

Contains FCC ID: 2AEMI-B404X

1.2.2 CE

The MODULAIR™ complies with European Union EMC Directive 2014/30/EU and conforms to the following technical standards (EN 55011, EN 61326).

Model: MODULAIR

Contains FCC ID: 2AEMI-B524

2. Installation and Hardware Setup

2.1 Unpacking

When you unpack your MODULAIR, you should have received the following:

• MODULAIR Air Quality Sensor

• Power supply and USB-C charging cable

• Mounting hardware (flanges with 4, 10-32 screws)

• 16 GB µSD card (pre-installed)

If any of these components are missing, please contact QuantAQ support via the in-app chat.

2.2.1 Device Overview

Upon opening your MODULAIR, it should appear as Figure 2.1 shows below, without the antenna attached. When attached, the antenna should be facing up to get the best service.

2.2.2 Device Front Panel

The front panel of the MODULAIR can be accessed by opening the lid of the enclosure. The panel provides access to the ON/OFF switch, the µSD card for local data logging, the internal battery status indicator (Battery Charge Status), and the device status LED (Device Status Indicator), all of which are shown in Figure 2.2.

Front Panel Screw

The front panel can be opened by unscrewing the Front Panel Screw, though should not be necessary under normal use. If it is opened, make sure that when re-closing, you do not "pop" out the µSD card. If so, you can simply push it back into place.

2.2.3 Device Base

Viewing the bottom of the MODULAIR, you can see the air intake covered by an insect-screen, the RJ11 jack for connecting the optional sonic anemometer, and the USB-C power in.

2.2.4 Device Circuit Board

The device circuit board is located under the front panel (Figure 2.2). To access, un-screw the Front Panel Screw and you will see the Core Board toward the lower left, as shown in Figure 2.4. The micro-USB cable is used exclusively for streaming logs directly from the device. While it does output some data, it is not designed to be used to connect to a data logger (this behavior is not supported). When used to collect logs, the MODULAIR must still be powered by the normal Power In USB-C connector shown in Figure 2.3.

2.3 Connections and Device Registration

The MODULAIR is shipped completely assembled, aside from the mounting hardware. Once the device is mounted and you have verified the power switch is in the OFF position, plug in the power supply and connect the USB-C cable to the bottom of the device. Once the power cable is connected, flip the power switch to the ON position. Upon receiving power, the Device Status LED (Figure 2.2) will flash green and eventually begin a sequence of slowly breathing cyan; this indicates the cellular connection is active and a session with the cloud server has begun.

The device will log data locally during the period where it is searching for cellular service and push the data to the server once a connection is established. If the LED indicator does not eventually begin breathing cyan, this indicates a cloud connectivity problem. Common errors and next steps can be found in Section 6.2.

To register your device, scan the QR code on the device registration card you received with your device. It is easiest to complete this step using a cellphone or tablet with a working internet connection. A laptop with a functioning camera will also work, though may be more difficult. It is also suggested that you first log in to the website (quant-aq.com) on the device you will use to complete this process. To register your device:

1. Use your camera to scan the QR code. This will open a tab in your default browser and will direct you to the device registration page.

2. Enter the fields for the information that the form asks for and click "Continue"

3. Enter the claim code found on the same QR code card → it should be a 6-character alphanumeric code.

4. Follow the instructions on the form and enter in data for the device location and other meta data. All of these can be changed in the future through the dashboard, so don't worry if you can't answer all questions at this time.

2.4 Installation

The MODULAIR can be mounted in several ways, depending on your exact use and the available mounting options available to you. The device is shipped with mounting flanges, which can be used to easily mount the device to several surfaces. Each flange is secured to the back of the device with two 10-32 stainless steel screws (included). Each flange includes three slots with the following dimensions:

Common installation approaches include:

• using high-strength zip ties to secure the device to a fence or post (not recommended)

• using screws to mount the device to a wall using the provided flanges

• Using u-bolts or similar to attach to a fence post, fence, or rail

• Purchase a pole mount kit from Polycase (the box supplier). .

The complete box dimensions are:

11.04" x 9.04" x 5.72" (280.42 x 229.62 x 145.29 mm)

2.5 Connectivity Considerations

3. Software Setup and Data

3.1 Data Structure and Outputs

There are three primary ways in which data can be accessed for the MODULAIR:

1. Raw data is stored locally on the µSD card

2. Data can be downloaded from the QuantAQ Cloud Console

3. Data can be downloaded from the QuantAQ API

The data formats are slightly different depending on which method you’ve used to access the data, each of which is documented below.

3.1.1 Data Stored Locally on the µSD Card

Data is collected and saved to an onboard µSD card every five seconds; each minute, these values are averaged and pushed to the cloud where they are available on the QuantAQ Cloud. It is unlikely you will ever need to use the locally saved data; however, you are more than welcome to use it if you would like. This section covers the locally stored data and how to understand it. When removing the µSD card to pull the data, make sure your device is turned OFF.

On the µSD card, you will find data files (with a prefix of DATA_YYYYMMDD.csv) and log files which are located in the logs directory. Log files contain debugging information about the onboard sensors and the cellular communication module. It is unlikely these logs will be useful to most users, though they are available to you if you would like to use them. It is highly recommended that you use the QuantAQ CLI (discussed below) to analyze them, as it will vastly reduce the amount of time needed.

Data files are written each day and can be read or analyzed using any programming language or spreadsheet program (e.g., Microsoft Excel). Each file begins with three meta-data rows describing the device model (row 1), device ID (row 2), and device serial number (row 3). See Figure 3.1A below. If you are automating your data analysis, you can skip these three rows. The fourth row contains the header information with the names of all columns. The remaining rows contain the data, where each row corresponds to a new 5-second sampling interval. The table below summarizes the columns.

The data outputs will change depending on the SKU (or model) of your MODULAIR. Most columns are constant except for the gas-phase columns.

3.1.2 Data Downloaded from the QuantAQ Cloud Console

Data are pushed to the QuantAQ Cloud with 1-minute time resolution and can be downloaded via the QuantAQ Cloud Console. When downloading data, you can select whether you would like to download the raw data, the final data, or both the raw+final data. Generally, the final data is what is desired, as it contains the final, cleaned data that is ready for analysis. The raw data is well-suited for researchers trying to investigate specific questions. When downloaded, the data is exported as a csv and contains the following columns:

3.1.3 Data Downloaded via the QuantAQ API

Data are available via the QuantAQ API at a 1-minute recording interval → the data available are the same as those available via the QuantAQ Cloud Console discussed above. The API is designed to allow engineers to build applications and map layers powered by the QuantAQ platform; however, it can also be a good way to automate data downloads, especially for large teams or lengthy download intervals. The data format is slightly different, as outlined below.

Each API call will return a paginated list of json objects with two keys: data and metaand will look something like the following:

The key definitions can be described as:

first_url: The unique url for the first page of data in the query

last_url: The unique url for the last page of data in the query

next_url: The unique url for the next page of data in the query

prev_url: The unique url for the previous page of data in the query

page: The current page number

pages: The total number of pages available for the query

per_page: The number of data objects per page

total: The total number of data objects in the query

The data object contains a list of all individual data objects for that page of data. You can query either the raw or the final data, both of which have different data values available. The final endpoint will return the following and will be different depending on the product SKU:

It contains several objects including the geo, met, and model objects. The descriptions of the individual data points are mapped to their respective columns in Section 3.1.2 above.

Note: If nothing appears in the right-hand column, the variable definition/name is the same

3.2 Understanding the Status Flag

Each row of data contains a single-byte data flag that describes the current state of the device. Flags are stored as unsigned integers and contain encoded information about each of the sensors on board. They are generated via a bitmask and can be decoded by reversing the procedure. To determine whether a specific flag is set, you can use the bitwise AND operation. If the flag's value is returned, then it is set. If a zero is returned, it is not set. This can seem complicated, so let's clear it up with a simple example.

Let's assume the value of the flag column is set to 4. We can perform a bitwise AND operation to check the result to see if FLAG_STARTUP was set (it wasn't). Below, we will check to see if the flag for the nephelometer is set (it is!).

The following table describes the flags, their value, and what they mean.

The following table describes the flags, their value, and what they mean.

3.3 Leveraging QuantAQ's Software Tools

To make data analysis easier, QuantAQ maintains several software programs designed to reduce the time you spend munging and cleaning your data. The most relevant piece of software is going to be the QuantAQ CLI (command line interface). The CLI can be used to easily concatenate files, merge files together, and de-code the flag and NaN bad data. It is quite simple to go from a large folder full of files to a clean, munged data file in less than a few commands. Full documentation and use cases can be found on the QuantAQ CLI website.

4. Maintenance and Service

There are no consumable or user-replaceable components to the MODULAIR-PM. If you believe a component is broken or not functioning correctly, please contact support via the in-app chat.

4.1 Reporting Issues

As a new product, issues will likely arise with the hardware, firmware, software, or all three! We do our best to prevent issues from arising and will be timely in fixing any that do arise. If you experience an issue or have a suggestion related to the MODULAIR hardware, please check the . If you do not find the answer you're looking for in the , you can open a ticket via the in-app chat.

5. Changelog

5.1 Hardware Changes

5.2 Firmware Changes

Please see our for a full history of all firmware support changes.

6. Appendix

6.1 Wiring Diagrams

Coming soon!

6.2 LED Indicator Status and Meaning