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 components 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) disease, 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 compounds (VOCs)
Volatile organic compounds (VOCs) 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 VOCs 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 regulates 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 Oxides (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 produce 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 technology requirements in many industrial permits. In addition, regulations specific to natural-gas boilers reduce emissions from these sources.