Monitor Your City’s Air Quality

[Radu Motisan]’s entry in the 2017 Hackaday Prize is a series of IoT Air Quality monitors, the City Air Quality project. According to [Radu], air pollution is the single largest environmental cause of premature death in urban Europe and transport is the main source. [Radu] has created a unit that can be deployed throughout a city and has sensors on it to report on the air quality.

The hardware has a laser light scattering sensor for particulate matter and 4 electromechanical sensors for carbon monoxide, nitrogen dioxide, sulfur dioxide and ozone (these sense the six parameters that are recognized as having significant health impact by multiple countries.) These sensors have2-yearear lifespan, so they are installed in sockets for easy replacement, and if needed, you can swap to different sensors to detect different things. The PCBs for the hardware are separated into a WiFi version and a LoRaWAN version and the software runs on an ATMega328 – the PCB has the standard six-pin ISP connection for programming.

The data collected is sent to a server where it is adjusted based on the unit’s calibration parameters and stored in a database per sensor. This makes servicing the sensors at the end of their life easier as all that’s required is replacing the sensors in the unit and changing the calibration parameters stored for that unit, the software changes are required. The server offers the data via a RESTful API so that building dashboards with the stats and charts become easy.

[Radu] used an off the shelf module as the first prototype and attached it to a car while driving around. He used this to test out the plan and work on the server. He then proceeded to designing the PCB hardware and the enclosure for the final unit. This work is an extension of [Radu]’s previous work, spotlit here in the 2015 Hackaday Prize, but also check out this project to put air quality sensors in the classroom.

18 thoughts on “Monitor Your City’s Air Quality

  1. Something you could sell to China, rather than the other way around, except that their goverment would ban them once people started to take notice of the readings from them. I wonder if you could build some of that functionality into a cell phone? I guess it would just record a lot of farting..

    1. Why would they ban them? The Chinese government openly publishes air quality data which agrees mostly with independent analysis. Furthermore do you think a little electronic gadget would be some kind of revelation to the people who have to cover their nose and mouth during the day to help breathe?

      1. The facts are that there has been oppression of groups critical of the Chinese governments environmental record so it is reasonable to conclude that if they saw such devices as stimulating discontent that they would ban them. They put short term stability above all else.

        1. The FACTS are that the Chinese government has been openly publishing AQI data since shortly after the US embassy and consulates in major cities began publishing their own AQI data as @garbz pointed out.

          They may be oppressing those critical, but the FACT is that they are publishing this data AND have made major commitments to reducing these publicly available (and accurate) numbers. Long-term commitments.

          –Currently an expat in Shanghai.

    1. More? Compared to what? Urbanisation rates in EU are very high for the west and air quality in cities is horrible as a result. They are putting effort into cleaning up their act, but it takes time. The city I live in has seen an 86% drop in diesel vehicles within the city in the past 6 years as the result of regulations.

  2. This is a great project and is likely to be a more effective metric for city environments but it has limitations that make it inaccurate to associate it to general “Air Quality”. It would be better described as an indicator for “Outdoor Air Quality”.

    It may be the case that the pollution this measures are associated with premature death but there is more to life than death! Quality of life is also a very important factor. Some pollution can cause very low quality of life but not necessarily death.

    In more urban environments it’s more likely to be indoor air pollution that causes illness and quality of life issues.

    In the US, almost 50% of buildings (both residential and work environments) have had some form of water damage that has resulted in rapid infection of biotoxins that produce mycotoxins which are very harmful to the 24% of the population that are genetically susceptible.

    These people develop a condition called Chronic Inflamituery Response Syndrome which I will write more about below.

    Unfortunately these biotoxins are best measured by polymerase-chain-reaction (PCR) tests such as ERMI but it would be great is some hacker could find an effective alternative even if PCR / ERMI was needed for confirmation. I have seen electronic testers that use the tape-lift method but I know noting about them.

    Without these tests biotoxins are indistinguishable from more common things like molds. In fact biotoxins are generalized to be molds in most literature.

    To give you an idea here are some more common biotoxins / moulds –


    Afatoxins are produced by Aspergillus parasiticus, Aspergillus favus, Aspergillus nomius, and various species of Penicillium, Rhizopus, Mucor, and Streptomyces.

    Afatoxin B1 (AFB1) is genotoxic, immunotoxic, hepatotoxic, mutagenic, and considered one of the most abundant, most toxic, and most potent naturally occurring carcinogenic substances known and is the leading cause of liver cancer in many developing countries.

    Sterigmatocystin produced by multiple species of Aspergillus is considered only slightly less toxic than afatoxin.

    Ochratoxin A is produced by Aspergillus ochraceus, Aspergillus niger, Aspergillus, and species of Penicillium, Petromyces, and Neopetromyces.

    OTA is a nephrotoxic, genotoxic, immunotoxic, and neurotoxic mycotoxin which is a known carcinogen in animals and a class 2B, possible human carcinogen.

    Associations have been found with human kidney disease including Balkan endemic nephropathy and focal segmental glomerulosclerosis (FSGS).

    For the curious here is a symptom list, these develop over time and most people do not get all symptoms –


    Muscles, Bones and Skin
    * Aches
    * Muscle cramps
    * Unusual pain
    * Ice pick pain
    * Joint pain
    * Morning stiffness
    * Numbness
    * Tingling
    * Skin sensitivity

    Head and Eyes
    * Headache
    * Light sensitivity
    * Red eyes
    * Blurred vision
    * Tearing
    * Positive VCS test

    Respiratory
    * Sinus problems
    * Cough
    * Shortness of breath

    Digestive
    * Abdominal pain
    * Diarrhoea
    * Appetite swings
    * Metallic taste in mouth

    Neurological
    * Memory issues
    * Focus/concentration issues
    * Word recollection issues
    * Decreased learning of new knowledge
    * Confusion
    * Disorientation
    * Tremors
    * Vertigo

    Energy
    * Fatigue
    * Weakness

    Emotions/Moods
    * Mood swings

    Temperature
    * Sweats (especially night sweats)
    * Temperature regulation or dysregulation problems

    Fluids
    * Excessive thirst
    * Increased urination
    * Static shocks

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