Table 2–
Pollutant standards index (PSI) for neighbourhoods during 2006–2007 in Tehran, Iran
PSI air status 2007–2008
City region
North
West
Central
East
South
Clean
121
76
42
98
0
Healthy
511
456
113
491
56
Nonhealthy
68
168
525
111
537
Extremely unhealthy
0
0
16
0
78
Dangerous
0
0
4
0
29