Air Quality Reports

Glossary of Acronyms and Abbreviations

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Ambient Air Quality Objectives


Environmental Beta-Attenuation Mass Monitor (Particulate Monitor)


Greater Vancouver Regional District (now called Metro Vancouver)


Mobile Air Monitoring Unit


Ministry of the Environment


Metro Vancouver (previously known as GVRD)


Quality Assurance / Quality Control


United States Environmental Protection Agency


Total Particulate Matter


Particulate matter 10 micrometers (μm) or less in diameter


Particulate matter 2.5 micrometers (μm) or less in diameter


What is an AAQO?

Ambient air quality objectives (AAQOs) are limits on the acceptable presence of contaminants in the atmosphere, established by government agencies to protect human health and the environment. The limits are used as an indicator/for comparison purposes to inform if the air quality in a certain area is generally acceptable. They are expressed in terms of a concentration (for example, micrograms per cubic metre, or parts per billion) measured over a specific period of time (for example, one hour, 24 hours or one year). MV air quality objectives are adopted for a number of contaminants including particulate matter and are one of the most stringent limits in comparison with the other jurisdictions.

What is Particulate Matter?

PM stands for particulate matter, the term for a mixture of particles found in the air. These particles come from a variety of sources, both natural and human-caused: industrial activities, construction sites, roads, vehicles and traffic, residential and industrial chimneys, wildfires, etc. Some particles, such as dust, dirt, soot, or smoke, are large or dark enough to be seen with the naked eye. Others are so small they can only be detected using a microscope.

These particles come in many sizes and shapes and can be made up of hundreds of different materials. PM10 (generally 10 micrometers and smaller) and PM2.5 (generally 2.5 micrometers and smaller) are two common size fractions used to assess air quality.

What is dustfall?

Dustfall is the term used to describe air particles that settle down (deposit) over a given area and time period, under the influence of gravity.

There is an important distinction between the fraction of particles that quickly fall out of the air (dustfall) and the portion that remains airborne for longer periods (particulate matter).

What does Neptune monitor and at what locations?

Neptune’s monitoring program includes the following elements:

  • PM10 (inhalable particulate matter with a diameter of 10 micrometers (μm) or less). Neptune is using three continuous PM10 monitors onsite and at the two offsite locations listed below.
  • PM2.5 (fine particulate matter with a diameter of 2.5 micrometers (μm) or less). Neptune is using three PM2.5 continuous monitors onsite and at the two offsite locations listed below.
  • Dustfall (DF) canisters, which are collected and analyzed monthly from the three PM monitoring locations listed below; and

Meteorological monitoring (wind speed and direction and other parameters) at three locations (onsite and at the two offsite locations mentioned below)

Where are Neptune’s monitors located?

  • Onsite:
    • On the roof of the electrical substation located on Neptune Terminals’ site at 1001 Low Level Rd.
  • Offsite:
    • Northeast of the Terminal on the roof of 340 Brooksbank Ave.

A pole mounted monitor in the northwest residential area of the Terminal at 618 2nd

Street East. This is the same location where Metro Vancouver placed its Mobile Air Monitoring Unit (MAMU) in 2014-15 for Moodyville Air Quality Monitoring Study.

What is an E-BAM and E-BAM filter tape?

An E-BAM is a continuous Beta-Attenuation Mass monitoring system used to measure the amount of particulate matter present in the air. The air is pulled over a filter tape which captures the particulate to determine how much is present in a given amount of air in a defined period of time.

How were monitoring location selected?

Neptune’s air quality monitoring locations and equipment were selected with Metro Vancouver’s (MV) assistance and approval, based on dispersion modelling (i.e. the locations in the neighbourhood at or close to the highest predicted concentrations). Neptune’s air quality monitoring results are presented to MV based on the identified intervals (quarterly and annually) in Neptune’s air permit.

What is a wind rose?

A wind rose is a graphic tool used to give a succinct view of how wind speed and direction are typically distributed at a particular location and period. The lengths of the bars on the wind rose indicate the percentage of occurrence of the various speed of winds; while the wind direction from which the wind blows is shown by the orientation of the bars. Wind roses included in Neptune reports represent the direction from which the wind is blowing.

What is a pollution rose?

The pollution rose is a graphic tool used to give a succinct view of which direction a pollutant will be blown in and how much is being blown.

What are 24-hour rolling averages?

The AAQOs are defined for different averaging periods. For particulate matter, the shortest averaging period is 24-hours. This means that particulate matter readings are averaged for the preceding 24-hours and compared to the AAQO to determine if there is an exceedance. This is done for each 24-hour period (e.g., 1 AM to 1 AM; 2 AM to 2 AM; 3 AM to 3 AM).

What is a frequency distribution?

Frequency distribution is a representation of how frequently a certain concentration range is measured by a given monitor, reported as a percentage. E.g., if concentrations between 0 – 5 µg/m3

are measured 56% of the time, the bar graph will indicate 56 for that concentration range.

Why do the onsite monitors sometimes have different levels of particulate than the community locations?

Neptune’s on-site monitor may show higher levels of particulate than the community monitors as it is located in a heavy industrial area. As this monitoring location is very close to several other terminal operations that cause particulate emissions, as well as trains and the high-trafficked Low Level Road, some short-lived particulate concentrations can be measured by these monitors. The other monitors are located offsite as an indicator of air quality in the surrounding area.