Trees Please Hamilton

Green Solutions to Air Pollution

Air Quality in Our Daily Lives

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Sean Angel, our summer intern

Sean hard at work collecting air quality data for us.

This blog was written by Sean Angel, a summer intern that was with us for two summers.  Here is his post.

After being inspired by this article: on air pollution exposure based on habits, I took one of Environment Hamilton’s Dylos air monitors to run for 36 hours during my daily life.

The Dylos is a moderately-priced particle counter that Environment Hamilton and the Hamilton Naturalist’s Club uses for Trees Please project to capture data on air pollution. The unit measures particulate, or PM2.5, which has been linked to cancer, an increase in asthma attacks, and other respiratory and cardiovascular disorders. When pictures of the Dylos are used, look for the number on the left – this count includes the small respirable particles that can penetrate deep into our lungs and bloodstream, and as a result this is what we focus on when data crunching.

I started at 8:20 pm after just taking a shower (this will become important later on), however, the Dylos only has so much onboard memory, and I ended up overwriting the first hour and half of the data eventually. I live in a small 2-storey house in East Hamilton. My bedroom is on the 2nd floor, as is the bathroom/shower. I was surprised to notice that the readings were quite high on the upstairs floor, in the 5000 range that I’d only expect to exceed near industry, construction sites, or on hot, sticky, smoggy days.

On the main level, the readings were significantly lower, but still a bit higher than I would have hoped for. I’m used to seeing readings like this in downtown Hamilton, where vehicle emissions are a concern:

In my basement, the readings were cut in half another time, back to more comfortable (but still not optimal) levels: 

I was not surprised to see readings in the 1000-2000 range – the windows were left closed and the air conditioners turned off for the majority of the day, so stagnant air had time to build up without very much circulation. The 5000 I observed in the upper level of the house was puzzling, but I chalked it up to the poor circulation.


36 Hours 1.png

Over time, the levels in my room did decline, and by the the time 10pm rolled around, readings were down to 1000. Overnight, the particulate levels continued to drop, likely due to a combination of settling from inactivity and good air circulation provided by A/C. The slight increase in readings closing in on 8 am was likely caused by a family member who was up and moving around before I was. This could have knocked dust into the air, causing the mild surge.

36 Hours 2

Time to get up! The readings spike a bit with increased activity. The upstairs in particular sees a lot of human activity in this time period, and a family members shower may also contribute to rising humidity levels that may influence the Dylos readings. They decline when I go to the lower level to scavenge up some breakfast. The peak around 9:45 was caused by more human activity, as I sorted clothes, packed my bags, and prepared for leaving the house.

36 Hours 3.png

Now I’m outside, heading to Powell Park in the Sherman Hub to meet up for Thursday morning Trees Please, which for me means air monitoring with a GPS in hand. The air was a bit worse outside than it is inside my house, and there’s many more variables in play now. I’ve excluded the first few minutes of GPS readings from the data set for my privacy.

36 Hours 4

Readings at Powell Park, taken around 10:05 am

The spikes up to 5000-7000 were all concentrated in the northwest corner of the Gibson neighbourhood, on Bristol and Barton Streets between Wentworth and Sanford. On Bristol, these high readings were accompanied by the sounds and smells of construction activity occuring near the Norman Pinky Lewis Rec. Centre. The Barton St. readings were even higher and came with another smell: tires.

Readings just outside the used tire shop on Barton St.

There is a used tire store that seemed to be producing high particulate emissions, and this store combined with the upwind construction emissions to yield the highest outdoor readings that day.

After the Trees Please walk, it was time to head back to the office. I used the Cannon cycle track on a Sobi named Brandon.

Cannon cycle track just west of Wellington

The only notable increase in the readings during the bicycle trip to the office were caused by a large (likely diesel) truck overtaking me near Ferguson, and City of Hamilton staff removing graffiti from the Beasley Park sign with something with a scent reminding me of nail polish remover (it was likely paint thinner).

The readings dropped substantially when I came into the office and got hooked up to a power source. They stayed consistently low for the next hour and a half.

Good to see the office air is healthy!

36 Hours 5.png

Lunchtime – I head to the City Centre across the street to eat lunch.

36 Hours 6.png

Walking down Wilson St. toward the City Centre


The initial fluctuations are me walking to the City Centre –  heavy traffic, road dust, people moving around, and vortices from the tall buildings all contribute to higher levels than generally seen in the Sherman Hub. The readings decrease, but still fluctuate a bit as I negotiate the City Centre. They stabilize once I sit down at one place.

I hope the Dylos is enjoying this quiet lunch date as much as I am.

The escalator I intended to take back to the office is out of service, so I have to take the elevator. I’m expecting higher particulate levels in an enclosed space with low air circulation, and I’m not disappointed.

When I exit the elevator and walk towards the entrance at York and James, I smell cooking food, maybe from the Middle Eastern place closer to where I was sitting.

Like burning firewood, food smells great being cooked, but it has an equally bad contribution to poor air quality.

As the smell goes away, so does the high readings.

Back outside, and the ground is wet – there must have been a short rainshower while I was eating lunch. I’d normally expect this to decrease the particulate by depositing it back onto the ground, but instead I’m greeted to even higher readings!

Walking back to the EH office

As soon as I step back inside the office, the readings drop and return to where they left off.

Back inside the office, the readings stay roughly constant until around 3 pm, when they begin to fluctuate and increase slightly. This could have been caused by someone opening a window, or just from office activity knocking some dust off of the floor. In any case, these fluctuations aren’t anything to worry about.

36 Hours 7.png

At 4:30, it’s time to go home, and hopefully just in the nick of time, as dark clouds are rolling in. The outside particulate readings are much lower now, roughly the same as they were in the office.

There’s a notable increase while I’m on the bus (starting around 40 data points) with a lot of fluctuation, however. Air channels in and out of the bus much more rapidly than in other places. When I exit the bus, it’s begun to rain.

Readings after just entering the bus

Same bus, just a few minutes later!

I slipped the monitor into a bag to protect it from the rain, but it continued record air quality. The final variations in the graph below may have been caused by inadequate air supply.

36 Hours 8.png

Food was being cooked on the stove when I got in to the house, resulting in a notable rise in the readings.

36 Hours 9

Food cooking on the stove doesn’t just increase your appetite.

Once the food was cooked, the readings would diminish significantly and level out at a steady decrease of around 500/hour. These readings would pick up towards 7 PM from my shower due to a humidity increase – this is a known weakness of the device.

Much lower readings now that time has passed and the small particulate has had time to settle.

36 Hours 10

No, you’re not misreading the graph. That’s sixty-thousand.

I left the device in my bedroom when I went to shower. After showering, I noticed that the readings had gone up from the humidity. They were now up at around 1500. I went back into the bathroom to apply deodorant: a dry-spray Axe product (pictured below).

Imagine my shock when I returned to my bedroom and saw this:

There’s a hallway between my bedroom and the bathroom. I can’t even smell the spray remnants from my bedroom, yet the readings have gone up considerably. Now I’m worried. I bring the device to my bathroom, and I get the first spike on that graph (approx. 33000). I normally only see readings this high near industrial areas with a large amount of drag-out and dust, dirt, and gravel visible on the ground. It’s been around a minute by this point – the aerosol has had time to disperse, yet the associated particulate remains suspended in the area in high concentrations. Now I’m interested – what would  the readings have been like in the room immediately after spraying? So, I test – I spray a small puff into the air in front of me, and bring the device up to face-height. The readings climb – and climb – and climb, past 30000, 50000, past the highest reading I’ve ever recorded (55000) and the highest reading ever recorded by Environment Hamilton (around 60000). Around 65000, I noticed the device the device started increasing from 0 again – it turns out, the Dylos records the measurement in 16-bits, meaning that the highest value that it can display is 65535. It reached around 4500, meaning that the actual particle count was approximately 70000. I was stunned.

I repeated this experiment a few minutes later to get video evidence:

Walking down the hallway from my bedroom to the bathroom a few minutes after triggering the 2nd spike:

Spraying a puff in the vicinity of the air monitor:

After taking the video, I went to the lower level, where the readings were also highly elevated (2000-3000) – the particulate dispersion was not just limited to the upper level of the house.

36 Hours 10 and a half

Just to confirm that the monitor itself still wasn’t saturated with aerosol, I took it outside to check the measurements there. I read 500-700, completely reasonable, and lower than earlier on in the day.

I returned to my room, and set the monitor down on a desk. Over the course of hours, the particulate dispersed and settled on the ground, and by 10pm, I was back to very low readings (100-200). The peak around 1000 data points into the graph below was from the monitor falling off the desk onto the floor, which stirred up the settled particulate.

36 Hours 11

Much better – 10PM that night

7:15 was wakeup time, and the spike shortly afterwards was pan-fried eggs being cooked on the stove. The particulate levels stabilized, they were kicked up at the end by me making my bed and moving around getting ready to go for the day. At 8:49 AM, I ended the experiment.

36 Hours 12

So, what was learned?

  • Barton between Wentworth and Sanford seems to have chronic air quality problems. It had the highest outdoor readings of the day, and this is consistent with other readings done in the area this summer. This could be caused by the various construction activities nearby, dense vehicle traffic, and/or activity from local businesses (most notably the tire shop).
  • Different modes of transport have different exposures to particulate pollution. The HSR bus had the highest and most variable particle counts – this might be something worth looking into on a wider scale. Although I didn’t encounter over-the-top readings while cycling back to the office, it’s important to keep in mind that the elevated breathing rates and physical exertion have an effect on your intake of particulate matter. Even if the ambient air pollution is better outside than on a bus, you may still inhale more particulate because of your increased breathing rate. It’s also more important when exerting yourself to avoid dirty air, especially if you have asthma or other vulnerabilities. As well, being on a bike can put you at risk to more direct sources of air pollution – the diesel trucks that passed by me on Cannon are a clear example of this. At a busier time of the day, I could have experienced much denser traffic and higher particulate levels as a result.
  • Avoid aerosol deodorants and other aerosol-based products! I imagine the high levels of respirable particulate that you’re exposed to with these cans is also common to air fresheners like Febreze. I’ve switched to a stick deodorant.

If you’re interested in using/borrowing one of our air quality monitors, there’s a couple projects you can get involved with this summer (including Trees Please, of course!):

Email to get involved with tree inventorying or air quality data collection!

Email to get involved with our Bicycle Air Monitoring (BAM!) program!





Author: treespleasehamilton

A project of the Hamilton Naturalists' Club and Environment Hamilton. Funding by Ontario Trillium Foundation.

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