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Air Contaminants


​A person’s health can be affected when exposed to air contaminants. Air contaminants can also cause economic and aesthetic impacts. The air contaminant of greatest concern in our region, due to its potential effects an​d prevalence, is fine particulate matter. Ground-level ozone is also of considerable concern due to its potential health effects, even though it is not directly emitted to the atmosphere. Volatile organic compounds (VOCs) are also of concern because they contribute to ground-level ozone, they can be odorous, and some compounds are toxic.

The majority of complaints rec​eived by our staff are attributable to odorous air contaminants.

Particulat​e matter

Particulate matter (PM) is the term for solid or liquid particles found in the air. Emissions of PM impact both health and visibility.

Of particular concern is PM2.5 or fine particulate matter, particles that are invisible to the naked eye at less than 2.5 microns in diameter. Fine particulate matter is small enough to enter the deepest portions of our lungs and contributes to such significant health problems as depressed immune system activity, disrupted enzyme levels, exacerbation of asthma, emphysema, bronchitis, pneumonia and heart disease. There is no safe level for PM2.5 exposure.

Significant sources of PM2.5 include older diesel engines and uncontrolled wood combustion such as open burning or residential fireplaces/woodstoves. ​Metro Vancouver regulates emissions of particulate matter primarily through limits in industrial permits and through Non-Road Diesel and Boiler Emissions regulations.

Ground-level​​ ozone

Ground level ozone is not emitted directly but rather is formed from reactions between nitrogen oxides (NOx) and volatile organic compounds (VOCs) in the presence of sunlight.  Ozone and fine particulate matter are the main compo​​​nents of what is commonly known as “smog”.

Ozone irritates the eyes, nose and throat, exacerbates asthma, COPD and other lung diseases as well as cardiovascular (heart) dise​ase, causes coughing, wheezing and headaches, and over time can cause permanent lung damage.  It also damages plants and buildings.

Significant sources of the precursors of ozone are motor vehicles and furnaces/boilers (for NOx), and consumer products​, motor vehicles, and petroleum products (for VOCs). 

In order to manage NOx and VOC​ emissions, some industrial permits contain limits on discharge quantities.  In addition, regulations that target gas stations, petroleum bulk handling facilities, automotive refinishing operations and boilers reduce emissions from these sources.

Volatile organic comp​o​unds (VOCs)

Volatile organic compounds (V​OCs) are gases released in the vapours from gasoline, vehicle exhaust, some paints, cleaning supplies, uncontrolled open burning, and even trees and other vegetation.

VOCs are known to react with nitrogen oxides (NOx) in the presence of sunlight to produce ground level ozone, a major component of smog, and a major health concern due to its impacts on the cardio-respiratory system.  In addition to impacts VO​​Cs can have when they form ground level ozone, they can also irritate the eyes, nose and throat, and cause headaches, loss of coordination or nausea.  Furthermore, some VOCs, such as benzene, are understood to be carcinogenic.

Metro Vancouver regul​​ates VOCs with discharge limits in some industrial permits.  In addition, regulations specific to gas stations, petroleum bulk handling facilities, automotive refinishing operations and boilers reduce emissions from these sources.

Nitrogen oxi​des (NOx)

Nitrogen oxides (NOx) are gases released primarily from combustion processes, such as motor vehicle engines or​​ natural-gas boilers, when oxygen and nitrogen in air react under high temperatures. The two components of NOx are nitric oxide (NO) and nitrogen dioxide (NO2).

NOx is reddish brown in colour, has a pungent and irritating odour, and contributes to visible haze in addition to being a lung irritant. In addition, NOx readily reacts with volatile organic compounds (VOC) in the presence of sunlight to pr​​oduce ground-level ozone, a major component of smog, and a major health concern due to its impacts on the cardio-respiratory system. NOx emissions are also a concern when they deposit on land or on water due to the potential for acidification or eutrophication.

Metro Vancouver regulates NOx with discharge limits or tech​nology requirements in many industrial permits. In addition, regu​lations specific to natural-gas boilers reduce emissions from these sources.​​

 Related links



Particulate Matter Fact Sheet, Particulate Matter Fact SheetParticulate Matter Fact Sheet
Ground-level Ozone Fact Sheet, Ground-level Ozone Fact SheetGround-level Ozone Fact Sheet
Nitrogen Oxides Fact Sheet, Nitrogen Oxides Fact SheetNitrogen Oxides Fact Sheet

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