Appendix 3.1 : Hong Kong Air Quality Objectives (AQOs)

[ Simple Table Format ]

Pollutant Averaging
time (ii)
Concentration in microgrammes per cubic metre
(μg/m3) (i)
No. of exceedances allowed per calendar year
Health effects of pollutant
at elevated ambient levels
Sulphur dioxide (SO2)
10-minute
500
3
Respiratory illness;
reduced lung function; morbidity and mortality rates increase at higher levels.
24-hour
125
3
Respirable suspended particulates (PM10)
24-hour
100
9
Respiratory illness;
reduced lung function; cancer risk for certain particles; morbidity and mortality rates increase
at higher levels..
Annual
50
NA
Fine suspended particulates (PM2.5)
24-hour
75
9
Annual
35
NA
Nitrogen dioxide (NO2)
1-hour
200
18
Respiratory irritation; increased susceptibility to respiratory infection; lung development impairment.
Annual
40
NA
Ozone (O3)
8-hour
160
9
Eye irritation; cough; reduced athletic performance; possible chromosome damage.
Carbon monoxide (CO)
1-hour
30,000
0
Impairment of co-ordination; deleterious to pregnant women and those with heart and circulatory conditions.
8-hour
10,000
0
Lead (Pb)  Annual
0.5
NA
Affects cell and body processes; likely neuropsychological effects, particularly in children; likely effects on rates of incidence of heart attacks, strokes and hypertension.


Notes:

(i)
Gaseous air pollutants are measured at 293K (20ºC) and 101.325 kPa (one atmosphere).

(ii) Refer to Air Pollution Control (Amendment) Ordinance 2013.

(iii) Respirable suspended particulates means suspended particles in air with a nominal aerodynamic diameter of 10 μm or less.

(iv) Fine suspended particulates means suspended particles in air with a nominal aerodynamic diameter of 2.5 μm or less.

(v) ’NA’ stands for Not Applicable.



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  2005 Copyright Important notices  Last revision date : May 2014