AQHI policy-171123-v1
Air Quality Policy
This policy has been developed by Triathlon BC to assist Race Directors and Technical Officials make an
appropriate decision when the Field of Play is impacted by low visibility or forest fire smoke.
LOW VISIBILITY
Low visibility is generally caused by fog/mist or darkness.
The swim leg of an event is not to commence unless:
• The first turning mark is clearly visible from the start line, and
• Each subsequent turning mark is clearly visible to competitors, and
• Every position on the course has a clear view of a safe exit location on the shore
The bike leg of an event is not to commence unless there is at least 100m visibility at all positions on the
course.
AIR QUALITY HEALTH INDEX
Overview
The Air Quality Health Index is standardised across Canada and provides a number from 1 to 10+ to indicate
the level of health risk associated with local air quality. Occasionally, when the amount of air pollution is
abnormally high, the number may exceed 10. The AQHI provides a local air quality current value as well as a
local air quality maximums forecast for today, tonight and tomorrow and provides associated health advice.
As it is now known that even low levels of air pollution can trigger discomfort for the sensitive population, the
index has been developed as a continuum: The higher the number, the greater the health risk and need to take
precautions. The index describes the level of health risk associated with this number as ‘low’, ‘moderate’, ‘high’
or ‘very high’, and suggests steps that can be taken to reduce exposure.
Calculation
The national AQHI is based on three-hour average concentrations of ground-level ozone (O
3
), nitrogen dioxide
(NO
2
), and fine particulate matter (PM2.5). O
3
and NO
2
are measured in parts per billion (ppb) while PM2.5 is
measured in micrograms per cubic metre (ug/m
3
). The AQHI is calculated on a community basis (each
community may have one or more monitoring stations).
First, the average concentration of the 3 substances (O
3
, NO
2
, PM2.5) is calculated at each station within a
community for the 3 preceding hours. This is considered valid only if at least 2 out of 3 hours are available at
the station. If more than 1 of the preceding 3 hours is missing the station average is set to "Not Available". This
part of the process results in three "station parameter averages" for each station.
Second, the 3 hour "community average" for each parameter is calculated from the 3 hour substance averages
at the available stations. If no stations are available for a parameter, that parameter is set to "Not Available".
This part of the process results in 3 community parameter averages.
Third, if all three community parameter averages are available, a community AQHI is calculated. The formula
is:
The result is then rounded to the nearest positive integer; a calculation less than 0.5 is rounded up to 1.
AQHI policy-171123-v1
Health Risk
Air Quality
Health Index
Health Messages for At-Risk
Population
Health messages for General
Population
Low
1-3
Enjoy your usual outdoor
activities.
Ideal air quality for outdoor
activities
Moderate
4-6
Consider reducing or
rescheduling strenuous
activities outdoors if you are
experiencing symptoms.
No need to modify your usual
outdoor activities unless you
experience symptoms such as
coughing and throat irritation.
High
7-10
Reduce or reschedule
strenuous activities outdoors.
Children and the elderly
should also take it easy.
Consider reducing or
rescheduling strenuous
activities outdoors if you
experience symptoms such as
coughing and throat irritation.
Very high
Above 10
Avoid strenuous activities
outdoors. Children and the
elderly should also avoid
outdoor physical exertion.
Reduce or reschedule
strenuous activities outdoors,
especially if you experience
symptoms such as coughing
and throat irritation.
FOREST FIRE SMOKE
Particle levels are the principal concern in forest fire smoke. The size of the particles in the air we breathe
affects their potential to cause health problems.
Particle pollution may contain substances like carbon, sulphur and nitrogen compounds, metals and organic
chemicals. The AQHI calculation uses coarse particles in the range of 2.5-10 microns in diameter. Fine
particles, with diameters less than 2.5 microns are often linked to health effects. Particles in this size range are
slow to clear from lungs when they are inhaled.
Particles from smoke tend to be extremely small, with a size range near the wavelength of visible light (0.4 to
0.7 microns). At this size range, smoke particles efficiently scatter light and make it difficult to see, and can be
inhaled deeply into the lungs. This is why these smoke born fire related particles are a greater concern than
larger particles.
Health Effects of Forest Smoke
Particulate matter exposure is the principle public health threat from short term smoke exposure. The health
effects of smoke range from eye, nose or throat irritation to serious problems such as reduced lung function,
bronchitis, exacerbation of asthma and even a risk of death.
Athletes are at risk when they are breathing deeply and rapidly.
Risk Assessment of Smoke Conditions
Not all areas have continuous official monitoring for AQHI or, Race Directors and Technical Officials may not
have available access to official monitoring station data, so a way of establishing particulate levels in the air
has been developed by NOAA. A visibility index gives a quick, alternative way to estimate smoke levels. Using
landmarks at known distances, an observer can provide a reasonable estimate of particulate concentration. It
would be wise to identify landmarks before they are needed and know the approximate distances to allow for
an effective visibility measurement.
AQHI policy-171123-v1
TABLE 1 : For estimating particulate matter concentrations from Visibility Assessment
Air Quality Category
Visibility in Km
Good
15 Kms and Up
Moderate | Unhealthy for
sensitive groups
5 - 14 Kms
Unhealthy
2.5 - 4 Kms
Very Unhealthy
1.5 – 2 Kms
HAZARDOUS
< 1.0 Km
When estimating particulate matter concentrations visually, it is important to face away from the sun.
Determine the limit of your visibility range by looking for landmarks at know distances. The visibility range is the
point at which even high-contrast objects totally disappear. (Example: a dark building viewed against the sky at
noon). Once visibility has been determined in kilometres, use Table 2 to identify the appropriate messaging
and actions based on the air quality category. The visibility index is not effective at night or when humidity is
high.
TABLE 2 : Appropriate Message and Actions based on the air quality category
Air Quality Category
Message
Actions for Events
Good
Visibility : 15 kms and up
AQHI 1-3
Ideal air quality for outdoor activities
Ideal conditions for an event
Moderate / Unhealthy for
Sensitive Groups
Visibility: 5-14kms
AQHI 4 - 6
Be aware of health effects of smoke
and related symptoms
Be aware of health effects of
smoke and related symptoms
Unhealthy
Visibility: 2.5-4kms
AQHI 7 - 8
Reduce or re-schedule strenuous
activities, especially if you experience
symptoms
Consider reduction of length
of events and / or cancellation
of junior events.
Provide warning to
competitors with respiratory
issues e.g. Asthma
Very Unhealthy
Visibility: 1.5-2kms
AQHI 9 - 10
Avoid prolonged strenuous activities
and stay indoors if possible
Consider reduction in length
of events.
Cancel or postpone event.
Cancel Junior Events
HAZARDOUS
Visibility: < 1.0km
AQHI 10+
Avoid all strenuous activities and stay
indoors
Cancel all events and training
Should the air quality be such that an event is impacted to the extent that a decision needs to be made as to
whether the event should be re-scheduled, reduced in length or cancelled, it should be done in consultation
with the Race Director or the Appointed Contingency Committee and the Technical Delegate for the event. The
final decision to modify the race plan will rest with the Race Director.
GENERAL MESSAGE to all Participants, Workers and Attendees at events impacted by Forrest Fire
Smoke: Seek medical Care if experiencing symptoms such as repeated coughing, shortness of breath or
difficulty breathing, wheezing, chest tightness or pain, heart palpitations, unusual fatigue or light headedness.