Sensors for environmental monitoring

Real-time monitoring of weather and environmental parameters is of primary importance to obtain local information on the territory, to be used for a variety of applications. Historically, this monitoring has always been carried out through a low number of professional stations located in strategic locations. The high cost and difficulty of managing these stations makes it difficult to spread them throughout the territory.

The current market is bringing out a new class of low-cost outdoor environmental monitoring devices that could change the way the environment is monitored, allowing, for example, even individuals or small businesses to cost-effectively monitor places of interest, or offering public institutions more extensive monitoring, federating a large number of popular sensors.

In these pages, we provide an analysis of the current situation, focusing on the aspects monitored in the framework of the TDM project.

Specific solutions based on these solutions will be developed within the project and integrated into a shared architecture for data acquisition, aggregation, analysis and forecasting.

Market analysis

In order to have a precise idea of the state of the art of the market of low-cost devices for outdoor environmental monitoring linked to Smart Cities, we have carried out a preliminary analysis of some ongoing or completed projects and of the main providers of "intelligent" solutions for the various types of problems related to the management of metropolitan cities.

There are so many initiatives worldwide because the optimal management of large urban centers has become an essential need given the increasing complexity of the issues related to them such as traffic, roads, emergency management, optimization of energy consumption, reduction of pollution, etc..

The CIO Review magazine recently published the list of the 20 most promising Smart City solution providers for 20171 , which certainly represents a good starting point for understanding the current situation of what can be defined as a real "market" in a phase of enormous development. The summary table is shown below, indicating for each supplier also the type of solution proposed.

For example, by focusing on specific projects with similar aims to the TDM project, we can mention:

Kansas City, Missouri, with the help of industrial partners Cisco, Sprint, Sensint, Sensing Systems and Think Big Partner, has installed an intelligent and connected system to improve life through mobile apps that address the city's challenges. Wi-Fi connectivity is implemented along a 2.2-mile stretch of the city tram line to support 25 digital interactive kiosks that provide residents with information about local activities and events. In addition, an intelligent lighting platform of 125 street lamps has been developed to reduce energy consumption and support better traceability of energy consumption. Partners are also developing a Living Lab to stimulate an entrepreneurial ecosystem of innovative solutions.

Hamburg, Germany is home to the third largest port in Europe, serving around 10,000 ships each year. The Hamburg Port Authority (HPA) has committed itself to a multi-year effort to create an intelligent infrastructure aimed at modernising and improving port operations, while enriching the quality of life for residents of the area. Initiatives include an intelligent road system that monitors and provides updates on port traffic to alleviate congestion in the area, along with an intelligent system that facilitates parking by alerting drivers of cargo vehicles to available spaces in real time. The port authority expects that the pervasive "IoT" approach will reduce the port's operating costs by 70% in the coming years.

Adelaide, Australia, is experimenting with several smart technology projects across the city to provide a range of real-time services to residents. Intelligent environmental monitoring is collecting data on environmental parameters such as carbon dioxide, fine particulates, noise levels and temperature. The availability of open data should serve to stimulate the design of solutions to improve the liveability of the city. A smart parking application allows city drivers to locate and pay for parking using smartphones, makes parking more accessible and convenient, while allowing city managers to monitor and manage the use of resources more effectively. In addition, even here an intelligent lighting system of the city will allow a reduction in energy consumption through real-time monitoring and remote management automatic and programmable.

Beijng, China IBM Green Horizons2. The IBM initiative is clearly, given the means available to the multinational company, of enormous scope and takes the form of specific initiatives such as that in the city of Beijng in China3 , where we want to use IoT technologies and widespread sensors to improve the air quality of the city that has reached very high levels of pollution. As an initiative, as far as we know, for commercial purposes, we do not have technical details on the type of sensors that IBM intends to use.

UK4, EarthSense, is a project that has similar aims to IBM's initiative in China and aims to monitor air quality in the UK using professional sensors with costs starting from £1500 for the control unit to which connect the various sensors with costs around £500. More specifically, the control unit they use is made by air/alphasense5 , prices and characteristics of the sensors they use can be found in the document listed at the bottom of page6.

Chicago7, Array of Things, instead, follows a philosophy similar to the one we intend to pursue in TDM. It uses an open sensor platform called waggle8. Some information on the platform and costs can be found here: Although open, a development platform that measures the environmental parameters of interest to us costs about $1500. However, as the platform is 'open', information is available on the sensors used, the information of which is summarised in the table below. A realistic line of development, for lower cost solutions, could be to use the sensors in the table or similar, and develop "in-house" a platform based on arduino and/or raspberry for their management.

Fig. 1: schematic representation of the Waggle sensor platform used in Array of Things.




Sensor(s) Used


Carbon Monoxide

Air Quality/Health

SPEC Sensors 3SP-CO-1000


Hydrogen Sulphide

Air Quality/Health

SPEC Sensors IAQ-100


Nitrogen Dioxide

Air Quality/Health

SPEC Sensors 3SP-NO2-20



Air Quality/Health

SPEC Sensors 3SP-O3-20


Sulfur Dioxide

Air Quality/Health

SPEC Sensors 3SP-H2S-50


Air Particles

Air Quality/Health (PM 2.5 to ~40)

Alphasense OPC-N2 (included in ~20% of nodes)


Temperature & Humidity

Weather Conditions

Honeywell HIH6130, Measurement Specialties HTU21D


Temperature & Barometric Pressure

Weather Conditions

Bosch BMP180



Weather Conditions

Honeywell HIH4030



Weather Conditions

Bosch Sensortec BMP180, Measurement Specialties TSYS01, Melexis MLX90614, STMicroelectronics LPS25H, Sensirion SHT25, Texas Instruments TMP112 & TMP421, U.S. Sensor PR103J2


Physical Shock/Vibration

Detect heavy vehicles, shock to street pole (e.g. accident)

Freescale Semiconductor MMA8452Q


Magnetic Field

Detect heavy vehicle flow

Honeywell HMC5883L


Infrared Light

Cloud cover, sunlight intensity




Cloud cover, sunlight intensity

LAPIS Semiconductor ML8511, Melexis MLX75305


Ultraviolet Intensity

Cloud cover, sunlight intensity

Silicon Labs Si1145


Visible Light

Cloud cover, sunlight intensity

AMS-TAOS USA TSL250RD, Avago Technologies APDS-9006-020


RMS Sound Level

Sound intensity (loudness)

Knowles SPV1840LR5H-B



Street conditions, traffic flow, events

ELP-USB500W02M-L 170, ELP-USB500W02M-L 140


Tab. 1sensors used in the Waggle sensor platform and estimated prices of the components for which we were able to obtain the relevant information.

Potential solutions that can be realised on the basis of the current market

In the following we will show you how it is possible to build monitoring units for environmental parameters on the basis of the current market, focusing on solutions similar to those that will be implemented for the TDM project.


To get an idea of how to structure the container of a self-built control unit, one can think of it as an end point for solutions adopted by commercial products of low cost, such as the BloomSky control unit, shown in the figure at side9 (cost about 300$).

This product is extremely interesting because it is organized with two solar panels and a backup battery that allow it to work autonomously. The presence of a webcam, aimed at the sky, could be of interest also for our purposes. For example, an automatic methodology could be developed to reconstruct the three-dimensional structure of the cloud field also by crossing with cloud field information from meteorological models.

Open AirSensEUR

Another interesting possibility to explore as a potential development platform is the one offered by AirSensEUR, an open data/sw/hw platform developed as part of a European project that relies on Arduino and manages a series of environmental sensors. The scientific report can be found in the document listed at the bottom of the page10.

Commercial air quality sensors for personal use in the home are also of potential interest, for example

Speck11, Foobot12, Uhoo13, Dylos14, TSI AirAssur15, UB AirSense16 or Oregon Scientific 10 Autosense17

These devices typically detect values of PM1.0 PM 2.5, PM10 and the VOCs present in the air together with the air temperature and humidity with a frequency of a few tens of seconds. They are sold as portable products that can also be used away from home.

Generally the data are qualitative indicating a level of air quality but in some it is possible to download the data from the device via Bluetooth.

In Italy we can cite the example of the Smart Healty Environment18 project, co-financed by the Region of Tuscany and concluded in 2015, which developed an innovative network for monitoring the quality of life according to the concentration of pollutants and microclimatic conditions, based on fixed and mobile stations for the city of Pisa.

Low-cost fine dust monitoring (MEDIUM)

An interesting low cost project, even just for teaching purposes, for the realization of a fine dust monitoring system called MEDIUM is described in the link at the bottom of page19.

SmartCitizen Project

Perhaps the most interesting project to be integrated in an infrastructure like TDM is SmartCitizen (, which provides the complete project for the construction of an open hw and sw environmental monitoring station based on arduino. The Smart Citizen Kit is a hardware consisting of a sensor and a card for data processing, a battery and an enclosure. The primary board is equipped with sensors that measure air composition (CO and NO2), temperature, humidity, light intensity and sound levels. Once configured, the device transmits the data measured by the sensors via Wi-Fi. The device's low power consumption means it can be placed on balconies and window sills. Power to the device may be provided by a solar panel and/or battery. The website describing the project mentions that the cities of Amsterdam, Manchester and Barcelona have already been involved in this initiative in various ways.

The range of sensors could be extended to include anemometers and rain gauges. In this case, the Arduino Weather Station Project20 can be a good starting point.


In these pages, we have provided an analysis of the current situation, focusing on the aspects monitored in the framework of the TDM project. This analysis shows that there is a flourishing market, within which some interesting basic solutions are available, both for the project and for experimentation by citizens, public and private bodies.

Specific solutions based on these solutions will be developed within the project and integrated into a shared architecture for data acquisition, aggregation, analysis, validation and forecasting.




















[19] http://wa8.jl