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Appendix 4: Basis for the guideline values for the new air contaminants

 

Contaminant Guideline values (µg/m3) Implied risk
(per 106)
Levels for risk of 1 in 106 (µg/m3) Ambient levels (annual average, or as specified) Comment
Ambient
(annual average)
Basis

Benzene

10 (now)
3.6 (2010)

EC (now)
UK (long-term goal)

44-75 (WHO)
16 (WHO)

0.13-0.23

~ 7 (urban)
20+ (traffic)

 

1,3-Butadiene

2.4

UK

17-72 (RIVM)
670 (US EPA)

0.03-0.14
0.0036

~ 1 (24-hour)

 

Formaldehyde

15

WHO (health) converted

196 (US EPA)

0.077

12 (17-day)
~ 30 (1-hour)

 

Acetaldehyde

30

WHO (health) converted

450-2700 (WHO)
66 (US EPA)

0.001-0.067
0.45

No NZ data
US ~ (2-4)

 

Benzo(a)pyrene

0.0003

Risk of 2-3 in 105 assumed acceptable

26 (US EPA)

0.00001

7-72 (24-hour)

 

Mercury (organic)

0.13

TWA/100

-

-

No urban data

 

Mercury (inorganic)

0.33

TWA/100

-

-

< 50 (7-day)

 

Chromium (VI)

0.0011

Assume risk of 1 in 105 is acceptable (between WHO and US EPA)

12-140 (WHO)

0.000007-0.00009

No NZ data

Ignores dietary intakes

Chromium
(metal and III)

0.11

100 x Cr (VI)

1.3 (US EPA)

0.00083

Arsenic (inorganic)

0.0055

Risk of 1 in 105 assumed acceptable (between WHO and US EPA)

8.3 (WHO)

0.00067

No NZ data

 

Arsine

0.055

RfC (US EPA)

24 (US EPA)

0.00023