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Health Effects
API levels have
been related to concentrations of ambient respirable suspended particulate
(RSP), sulphur dioxide (SO2), carbon monoxide (CO), ozone
(O3) and nitrogen dioxide (NO2) over a 24-hour
period based on the potential health effects
of air pollutants.
API level at
or below 100 means that any pollutant levels are in the satisfactory
range over 24 hour period, which poses no acute or immediate health
effects. However, air pollution consistently at 'High' levels (API
of 51 to 100) in a year may mean that the annual HKAQO for protecting
long-term health effects could be violated. Therefore, chronic health
effects may be observed if one is persistently exposed to API of
51 to 100 persistently for a long time.
An API level
in excess of 100 means that levels of one or more pollutant(s) is/are
in the unhealthy range. The EPD has provided advice
to public regarding precautionary actions to take for such levels.
|
API |
Air
Pollution
Level |
Health Implications |
| 0
to 25 |
Low |
Not
expected |
| 26
to 50 |
Medium |
Not
expected for the general population |
| 51
to 100 |
High |
Acute
health effects are not expected but chronic effects may be observed
if you are exposed to such levels persistently for a long time. |
| 101
to 200 |
Very
High |
People
with existing heart or respiratory illnesses may notice mild
aggravation of their health conditions. Generally healthy individuals
may also notice some discomfort. |
| 201
to 500 |
Severe |
People
with existing heart or respiratory illnesses may experience
significant aggravation of their symptoms. There may also be
widespread symptoms in the healthy population (e.g. eye irritation,
wheezing, coughing, phlegm and sore throats). |
|
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