same year (2001) Detroitís annual PM  average for the
Fine/Respirable
10
3
PSMA was 34 µg/m ; the annual average for the West
Particulate Matter (PM )
2.5
3
End Monitoring site was 46 µg/m .  During 2000, the
monitoring station at W.End approached the 24-hour
The proposed 24-hour PM  standard is met when the
2.5
3
(Ref. 37)
standard with a value of  146 µg/m
three-year average at the 98th percentile is less than or
3
equal to 65 µg/m .  Of  the 11 monitoring stations, eight
In October 1999, the Wayne County Dearborn monitor
were able to provide three years of  data.  All these
3
site had a 24-hour concentration of  156 µg/m , which is
stations were below the standard; averages varied from
3
standard (Ref. 38).
above the 150 µg/m
3
3
to 47 µg/m  (at Linwood Site).  Wayne County
40 µg/m
(Linwood site) also experienced the highest annual 24-
3
hour 98th percentile measurement (51.7 µg/m ) in 1999
(Ref. 39).
th
Percentile PM  Concentrations by Individual Monitoring Stations,
TABLE 29
Twenty-four Hour 98
2.5
in Greater Detroit, 1999-2001
th
3
Percentile, Rounded to Nearest one µg/m )
(98
3
NAAQS is 65 µg/m
Stations
1999
2000
2001
Mean
New Haven
31.9
33.2
42.0
36
Oak Park
42.8
40.7
39.4
41
Southfield
~
~
44.2
44
Allen Park
49.0
41.8
48.3
46
44.1
34.6
40.1
40
Detroit - W. Fort
50.2
44.5
42.9
46
Detroit - Linwood
51.7
44.0
46.0
47
Detroit - E. Seven Mile
~
42.0
42.0
42
Livonia
38.4
35.9
44.7
40
Dearborn
45.1
45.1
43.2
44
Wyandotte
45.0
42.7
46.6
45
~No data provided
Based on available, but limited data, the indication is that
3
mean for Oak Park in 2000 was 15.4 µg/m , which is
the annual arithmetic mean would be the more critical
3
above the NAAQS of  15.0 µg/m .  However, as the
standard with respect to future nonattainment designa-
criteria to determine the annual arithmetic mean states
tion, when compared to the 24-hour 98th percentile
that it is the mean value averaged over three years, Oak
levels (Ref. 40).
Park remains within the standard.  However, data from
stations at Allen Park (1 & 2), W. Fort St., Linwood,
Table 30 provides the actual calculated annual arithmetic
Dearborn and Wyandotte suggest that compliance with
mean for each PM  station as it would be averaged over
the pending standards may prove difficult at these
2.5
the three years.  For example, the annual arithmetic
locations.
37