Participatory Air Quality Monitoring



I met my Professor friend at the EXIT of an international exhibition on air quality monitoring instruments in Mumbai. This exhibition had stalls of some of the leading suppliers of automated air quality monitoring instrument suppliers from all over the world. It was a great display of sophisticated instruments across some 50 stalls with seminars concurrently held. There must be at least 1000 footfalls a day. Most visitors were industries who were forced to install automatic air quality monitoring stations by the Government.

I asked the Professor how was the experience.

He seemed quite happy but not very excited. “It’s a good expo but I have some other views”. He said with a pause. “We need to chat one of these days”. I knew that given my friends hectic work schedule, this chat was never going to happen. Chatting with the Professor had always been interesting and stimulating. So I suggested that we sit at one of the restaurants outside the EXIT gate for some coffee. “They have a varandah behind and they let you smoke there” I told him as additional information – as if it mattered.

We picked up a table with a round top and cane chairs and ordered for Ethiopian coffee that was served in large cups with some bitter cookies. When the waiter brought an ashtray for the Professor, the “stage was all set” for our conversations.

He took a deep puff from his cigar and said “Monitoring with sophisticated instruments is fine. We do need to have good quality, high frequency air quality data on key parameters but what I don’t like is the absence of the involvement of people.  We need to involve people in environmental monitoring if we want to see action. Most of the times, monitoring remains a “bilateral” activity between the “polluter” and the ‘regulator”. People or the key stakeholders come to know the outcomes of this bilateral transaction only when there are serious violations leading to punitive actions or have legal consequences.

“People watch on TV or read occasionally in the newspapers graphs and statistics on ambient air quality, especially how it is much higher than the standard. Firstly they don’t understand the terms (parameters and units) and secondly they don’t know what should be done, or what the Government is doing about it. It is often a passive receipt of information”

I said you need something sensational to happen if you want to make people understand how bad our ambient air quality is. You may know that United States may curb President Barack Obama’s early morning schedule during his visit to Delhi this month. Air pollution monitoring agencies have found that  the levels of ‘PM2.5‘ (term used to describe fine, respirable particles) that get lodged in the lungs are likely to be in the range of moderate to high in the period while Obama will be in Delhi. So Obama may find difficult to be chief guest at the Republic Day parade which is held in the open and in the morning when air pollution levels are usually high.   He will probably have to wear an oxygen mask on the stage and look like Darth Vader of the Star Wars. This should wake up citizens of Delhi and force the Government to take some concrete actions to reduce the levels of ‘PM2.5 or not invite people like Obama again who have poor pollution resilience

The Professor smiled.  “You cannot ask the US President however to visit all polluted cities in India just to raise awareness of the Indian citizens – and his travel will cost more than Ministry of Environment’s budget. We have to find ways ourselves”. He rested his cigar on the ash tray.

Many years ago, in Mumbai, at Shivaji-Park I did an experiment on how to involve citizens in air quality monitoring.  Here some 200 odd citizens participated. We don’t need to make use of sophisticated instruments many times. Even basics like dust jar work. So I used dust jars that were sponsored for me by one of the major polluting industry of Mumbai.(They wanted to feel “good”). A call was given through newspaper (that was kind enough to publicize at no cost) asking interested citizens to assemble at the Shivaji-Park Gymkhana if they were interested to know about the air quality in Mumbai.

On a Sunday morning, some 200 citizens from different corners of Mumbai walked in. They represented all ages, gender and professions. I gave a 10 minute presentation on the basics of air pollution in cities and then spoke about the dust jar. Idea was to give every attendee a dust jar that they would place in the balcony or terrace with as much free air flow possible. The jar was to be kept for one week and all were expected to meet again at the Gymkhana, get the dust jar weighed and compare the results. Some of the students then showed the participants how the dust jar works. Names and addresses of the citizens were recorded (and later mapped).

Dust Jar

(picture sourced from

I think the idea of comparing dust fall levels really motivated the citizens to come back on next Sunday. My students did some random visits to some 20 houses across the city to check if the dust jar was placed alright – and this also helped in some sort of a reminder.

On the next Sunday we got more than 200 citizens as they brought along their neighbours and friends. All were curious. We weighed each dust jar and couple of my students did a quick mapping of the dust levels on the map of Mumbai to project on a screen.

I had organized for the display of lungs of industrial workers that were preserved in jars with formalin. This was courtesy KEM hospitals Air Pollution & Heath Unit. These jars showed how much of particle lodging had happened in the lungs of the industrial workers due to exposure to dust in the work space. While my students were doing dust fall mapping, the citizens crowded around the tables to see the “display of consequences”. This was certainly scary. I could hear first the whispers and later voices that were raised.

When Mumbai’s dust fall level map was projected, it led to an intense debate. Why are the dust fall levels high here and why here so low?  What dust fall levels are permissible? And what can we do about it?  One participant said that particle size should also matter and not just the weight. Another one said that local release of dust e.g. due to construction activities will make the difference. All were excited for more knowledge and came up with suggestions for city-wide as well as local actions. They wanted me to repeat this exercise at the terraces of schools and involve school children and teachers.

“Let the students get involved as an assignment where they would record dust jar levels in various seasons – see the variability and whether the trends were decreasing or rising. At the end of the year, all school principals should get together, compile data and publish a report for the citizens and the Government”

Wow – I exclaimed. “That’s real participatory air pollution monitoring. Much better than just making use of automated instruments. Your experiment is unique as it builds citizen awareness, imparts education. Importantly it promotes ownership, opens collaborations and leads to collective actions.

So did you repeat the “experiment” I asked.

The Professor extinguished his cigar and I asked for the bill.


I did this experiment in 1985 in Mumbai. Always wanted to repeat, escalate and replicate but couldn’t do so for various reasons. Would love to action again. May be through Ekonnect.  If anyone is interested to emulate this experiment, do let me know. I will be most happy to guide/help.

The dust jars were used heavily in China in1990s for ambient air quality monitoring. There have been interesting Chinese publications on the dust fall technique and results. Of course the method has its own limitations. There are however several extensions possible.

Even more recently, dust jars are used. See “Evaluation of Dust fall in the Air of Yazd” by K. Naddafi, R. Nabizadeh, Z. Soltanianzadeh, M. H. Ehrampoosh in Iran (

Putting science to society is the key. A lot happens when done well.


Cover picture sourced from



  1. Very good, Prasad. With my students, I did similar exercise, using plants on which dust deposits were monitored monthly, for a year The trend was clear, deosits increasing with progress of dry season in Mumbai. Results also brought out high, moderate and low levels of dust pollution in different parts of the city, south, north west, north east and so on. Results were presented in Tropical Ecology Conference in Kuala Lumpur in 1979 and appeared in the Proceedings.
    Would like to repeat again, when possible.

  2. Great. Can you share with me the copy of your publication? Let us meet up to launch participatory environmental monitoring in Mumbai. Will call you next week

  3. Wondering if it would make sense in one of the african cities where I work, such as Accra, Dar esSalaam, Addis or Durban.

    1. It would work practically everywhere! all kinds of cities.You need to make a plan first – city profiles, maps, key local institution who woud coordinate, get buy in from local government, procure dust jars, get support from the media etc. Do a pilot in one city asking other city “leaders” to be present.Then replicate. Hold a joint workshop. Ensure that this activity works on a “program basis”. Hope this helps

  4. Excellent, Prasad. I tried a similar exercise in Chennai with some enthusiastic school students whom I’s helping with in their environmental project. I didn’t use jars but some filter paper sheets framed using cardboard and hung by threads in the windows. It’s in April, when it’s hot and no rain.I’d only 10 volunteers and they all could see the dust layer. We’ld also see it’s less in houses which had tree cover. I didn’t take it up further to get the community involved. But certainly would love to do the participatory monitoring as you suggest.
    There’s a lot more environmental awareness among people today, thanks to lot of media work. Nevertheless, the participatory environmental monitoring may still work. Only problem is the follow up – I’m afraid that we lack the mechanisms to make our regulators and polluters to take necessary actions. Beach clean ups have been more frequently done by many voluntary organizations in chennai showing the garbage problem but still nothing comes of it.

    1. Dear Professor

      i will be very interested to learn more about your work with filter paper sheets. Can you share with us from your archives? When I visit Chennai next, will meet up with you.

      Best regards

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