Air pollution

Recent research1 examined pandemic trends among eight southwestern Ontario cities for four common pollutants:  nitrogen dioxide, fine particulate matter, carbon monoxide and ground level ozone.  It found that Hamilton pollutant levels did not change, with the exception of lower carbon monoxide in April 2020. The continuation of Hamilton’s industrial sector as an essential service, along with pollutants from US sources, were suggested as possible explanations.  Several other cities did experience drops in pollutants due to lower traffic and industrial activity.   

Overall, air pollution in Hamilton has improved over the past two decades.  As Clean Air Hamilton reported in the 2016 Annual Report, Hamilton’s air quality is about 90% better than it was in the 1970s.  

PollutantNumber of YearsTotal % Decrease%/year
Total Suspended Particle (TSP)2055%2.8%
Particulate Matter 10 (PM10)1933%1.7%
Particulate Matter 2.5 (PM2.5)1726%1.5%
Nitrogen Dioxides2053%2.6%
Sulpher Dioxides2047%2.4%
Total Reduced Sulpher20100%5.3%
Polycyclic Aromatic Hydrocarbons (PAH)1976%4.0%

Source:  Clean Air Hamilton 2016 Annual Report2

In spite of these long-term trends, the majority of these pollutants increased between 2016 – 2018; including total suspended particles, PM10, PM2.5, Sulpher Dioxides, and ground level ozone.3

Smog days or the similar Special Air Quality Advisories are another way to measure air pollution.  The number of these events has fallen dramatically in Hamilton since their peak between 2002 – 2005, when there was an average of 18 smog days annually.  Since 2014, Hamilton has not had one Special Air Quality Advisory or smog day.4  This progress is due primarily to the closure of the Nanticoke coal-fired power plant, as well as coal-fired power plants in the United States Midwest.5 

Climate change, average July temperatures and greenhouse gas emissions

An outcome of climate change is higher average temperatures.  With an average temperature of 23.5 C, July 2020 was Hamilton’s hottest in over 60 years.6  Moreover, July temperatures from 2016 – 2020 were the highest of any five-year period since 1960.  Global trends are similar:  NASA’s Goddard Institute for Space Studies recently confirmed that the last seven years have been the warmest globally.7

“The last seven years have been the warmest seven years on record, typifying the ongoing and dramatic warming trend,” said GISS Director Gavin Schmidt. “Whether one year is a record or not is not really that important – the important things are long-term trends. With these trends, and as the human impact on the climate increases, we have to expect that records will continue to be broken.”

Greenhouse gas emissions — the release of carbon dioxide, methane and other gases — are the leading contributors to climate change.  In Hamilton in 2018, total emissions were 11.8 million tonnes of CO2 equivalent: an increase of 300,000 tonnes from 2017.8  Emissions have edged up since 2016 when 11.2 million tonnes were released.  The leading sources of emissions in Hamilton are steel and other industry (72%), transportation (14%), residential (7%), commercial (6%), waste, water, and agriculture (less than 1% each).  Since 2006, all sources of emission, except transportation, have fallen.9

Waste diversion

The amount of waste being diverted from landfills through green bin, blue box and leaf/yard waste programs stayed steady over the past year at 40%.10 This is an improvement from 2018 when only 34.3% of waste was diverted,11 but a drop from 2010 – 2012 when 49% of waste was diverted.12 Hamilton’s waste diversion target is 65%.

The actual amount of waste that went to landfill in Hamilton in 2020 was 142,000 tonnes, up slightly from 128,500 tonnes in 2019, and similar to 146,500 tonnes in 2018.   From 2019 – 2020, the amount of waste that was recycled increased 6.6%, and composted leaf and yard waste increased 7.7%, but green cart usage fell 6.4%.13  

Percent days beaches are open

All Ontario beaches were closed by provincial order on March 30, 2020 due to COVID-19.  In Hamilton, beaches opened on June 19, 2020 with new precautions including social distancing.   

Since reopening, the three Lake Ontario beaches (Beach Boulevard, Van Wagner’s, and Confederation Park) were open every day, similar to 2019, and up from 85% in 2010.  The Pier 4 beach was reopened for 2018 after long-standing water quality issues (primarily attributable to waterfowl contamination) improved, and was open just over 50% of days.   Bayfront Beach has remained closed to swimmers since 2017.14

Tree canopy coverage

Having an adequate tree canopy in urban areas can have a positive effect on physical and mental health, and also offers substantial environmental benefits.  A healthy urban forest – equitably distributed among neighbourhoods – is essential for CO2 reduction, for cooling effects that mitigate urban heat islands, and for improved air quality (a mature tree in full leaf can reduce PM 2.5 levels by as much as 50%.15 In 2021, tree canopy coverage was 21.3%, up from 19% in 2010. 

The emerald ash borer has destroyed thousands of trees in Hamilton.  City of Hamilton staff have set a target of 30% canopy by the year 2030, and over the last year, have planted over 12,000 trees – which has just kept pace with the loss of ash trees.16

A substantial portion of Hamilton’s tree canopy includes major urban green areas like the Niagara escarpment, and without these major areas, our canopy coverage would be much lower.  Many neighbourhoods have very low rates of canopy coverage, and these neighbourhoods generally correlate to rates of low income:  the lower income the neighbourhood, the lower the amount of tree canopy coverage.  As mentioned above, this can have serious implications for physical and mental health.17

[1] Al-Abadleh, H., Lysy, M., Neil, L., Patel, P., Mohammed, W. (2021).  Rigorous quantification of statistical significance of the COVID-19 lockdown effect on air quality:  The case from ground-based measurements in Ontario, CanadaJournal of Hazardous Materials, 413. 
[2] Clean Air Hamilton (2016).  Annual Report.  
[3] Clean Air Hamilton (2019).  Progress Report 2018
[4] Ibid.  As of May 1, 2021. 
[5] Environment Hamilton.  Personal Communication.
[6] Author’s Calculations from Government of Canada, Average Monthly Temperatures
[7] Goddard Institute for Space Studies (2021).  Global climate change facts
[8] The Atmospheric Fund (2020).  Reality check:  Carbon emissions in the GTHA
[9] Ibid.
[10] City of Hamilton (2021).  Public Works 2021 Operating Budget.  Presented to City Council, January 27, 2021. 
[11] City of Hamilton (2019).  Public Works 2019 Operating Budget.  Presented to City Council, January 22, 2019. 
[12] City of Hamilton (2010-2014).  Public Works Annual Operating Budgets.  Cited in Hamilton Community Foundation’s 2018 Vital Signs
[13] City of Hamilton (2021).  Public Works 2021 Operating Budget.  Presented to City Council, January 27, 2021.
[14] All information from:  City of Hamilton (2019).  Public Health Services Beach Monitoring Report.
[15] Environment Hamilton, personal communication.
[16] Ibid.
[17] Ibid.