PRO't 

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

RESEARCH TRIANGLE PARK, NC 27711 

November 5, 2008 

OFFICE OF 

AIR QUALrrY PLANNING 

AND STANDARDS 

MEMORANDUM 

SUBJECT: 

FROM: 

Nitrogen Dioxide (NO2) Descriptive Statistics Tables 

Rhonda Thompson ••_•. 4- • 

Air Quality Analysis Gr6up (C304-0) 

TO: NO2 NAAQS Review Docket 

Nitrogen Dioxide (NO2) monitoring data for 2004-2006 were pulled from the Air Quality 

System (AQS). Alternative NO• design values were calculated for monitors that were at least 75 

percent complete for hours in a day and days in a quarter and had all 4 quarters and all 3 years. 

Table shows the percent of U.S. counties with monitors (and percent of population in counties 

with monitors) that did exceed alternative NO2 standards. The alternative forms are the 3-year 

average of either the 99 th 

or 98 th percentiles of the daily 1-hour maximum. The alternative levels 

for either form are 0.20, 0.15, 0.10, or 0.05. Population is in millions and the number of counties 

is in the top row and percentages are in the tables. 

For the 17 areas in Tables 2 and 3, the monitoring data were aggregated to either the 

Consolidated Metropolitan Statistical Area (CMSA) or, if no CMSA, the Metropolitan Statistical 

Area according to the 1999 Office of Management and Budget definitions (January 28, 2002 

revision). The monitoring site within an area that had the highest 1-hour design value on a given 

metric was chosen as the source of that metric value for the area. Table 2 has the 2 na through 9 th 

highest and the 99 th and 98 th percentiles of the daily maximums for each of the areas. Table 3 

shows the ratios of all of the possible metrics (both the 99 th and 98 th percentiles of the daily 

maximum and daily average) with each other and the current metric (annual average) for the 17 

areas. Each ratio is rounded to the nearest hundredth. For the alternative daily metrics, the 

statistics were computed for each year and then averaged over 2004-2006; while the form of the 

current metric, the annual average, is the maximum of the annual averages over 2005-2006. 

Three of the 17 areas did not meet all completeness requirements above and, therefore, only the 

complete year data were used in the calculations. Detroit monitors 261630016 and 0019 were 

complete for 2006 but only monitor 0019 was complete for 2004 and 0016 for 2005; as such, 

Intemet Address (URL) http://www.epa.gov 

Recycled/Recyclable Printed with Vegetable Oil Based Inks on Recycled Paper (Minimum 25% Postconsumer) 
only the 2 complete years were included in the averages. The Jacksonville monitor was only 

complete for 2006. The Provo monitor was only complete for 2004 and 2005. 

Attachment: Tables 1-3 

cc:. Phil Lorang 
Table 1 Predicted percent of counties with monitors (and percent of population in counties with monitors) exceeding alte

Alternative Number of counties with monitors (population in 1000s) 

Standards 

and Levels 

(ppm) 

Total counties 

(population in 

millions) Northeast Southeast 

Industrial 

Midwest 

Upper 

Midwest Southwest Northwest 

138 (93.9) 31 32 20 12 9 20 

Percent of counties, total and by region, (and total population) not likely to meet standard and level* 

3 year 99th percentile daily 1 hour max: 0.20 0 0 0 0 0 0 0 0.15 0 0 0 0 0 0 0 0.10 0 0 0 0 0 0 0 0.05 59 (79.6) 77 41 80 17 56 55 3 year 98th percentile daily 1 hour max: 0.20 0 0 0 0 0 0 0 0.15 0 0 0 0 0 0 0 0.10 0 0 0 0 0 0 0 0.05 46 (63.4) 55 34 60 17 44 45 * Based on 2004-2006 data for sites that are at least 75% complete for hours in a day and days in a quarter and has all 4 

As such, these estimates are not based on the same air quality data that would be used to determine whether an area wo

standard or set of standards. These estimates can only approximate the number counties that are exceeding the given st

and should be used with caution. 

** "Outside Resions" include Hawaii. 
Table 2. NO2 Daily Maximums and Percentiles for 2004-2006. 

2004-2006 NO2 Daily Maximums Percen

Location 2nd 3rd 4th 5th 6th 7th 8th 9th 99th Atlanta 0.083 0.079 0.078 0.074 0.073 0.072 0.070 0.070 0.078 Boston 0.069 0.067 0.064 0.063 0.062 0.060 0.059 0.059 0.064 Chicago 0.103 0.094 0.093 0.090 0.090 0.088 0.088 0.088 0.093 Cleveland 0.075 0.074 0.072 0.070 0.069 0.066 0.065 0.064 0.072 Denver 0.094 0.089 0.086 0.082 0.079 0.077 0.073 0.072 0.086 El Paso 0.085 0.080 0.075 0.072 0.071 0.068 0.067 0.066 0.075 Las Vegas 0.042 0.040 0.039 0.039 0.038 0.038 0.037 0.037 0.039 Los Angeles 0.110 0.095 0.095 0.089 0.088 0.084 0.083 0.081 0.095 Miami 0.065 0.060 0.059 0.058 0.057 0.056 0.054 0.053 0.059 New York 0.112 0.099 0.093 0.090 0.086 0.084 0.082 0.081 0.093 Philadelphia 0.065 0.062 0.060 0.059 0.058 0.057 0.056 0.054 0.060 Phoenix 0.107 0.097 0.093 0.090 0.089 0.086 0.084 0.083 0.093 St. Louis 0.066 0.065 0.064 0.064 0.063 0.063 0.063 0.063 0.064 Washington DC 0.102 0.088 0.079 0.075 0.072 0.066 0.065 0.063 0.079 These are 14 of the 17 areas in the Draft REA; 3 areas did not meet completeness requirements: 

Detroit, Jacksonville, and Provo. 

Based on 2004-2006 data for sites that are at least 75% complete for hours in a day and days in a quarter and has all 4 q

As such, these estimates are not based on the same air quality data that would be used to determine whether an area wogiven standard or set of standards. These estimates can only approximate the number counties that are exceeding the given st

and should be used with caution. 

2004-2006 NO2 Daily Maximums Percen

Location 2nd 3rd 4th 5th 6th 7th 8th 9th 99th Detroit * 0.062 0.060 0.058 0.057 0.056 0.054 0.054 0.053 0.058 Detroit ** 0.059 0.057 0.054 0.053 0.052 0.052 0.050 0.050 0.054 Jacksonville *** 0.054 0.05 0.049 0.049 0.049 0.048 0.048 0.048 0.049 
Provo **** 0.071 0.066 0.065 0.065 0.064 0.063 0.063 0.062 0.065 

* Detroit monitor 261630016 was complete for 2005 and 2006, 2004 was ignored in the averages. ** Detroit monitor 261630019 was complete for 2004 and 2006, 2005 was ignored in the averages. 

*** Jacksonville was only complete for 2006. **** Provo was only complete for 2004 and 2005. 
Table 3. Ratios of proposed alternatives and the current NO2 standards. 

2004-2006 

Daily 

2004-2006 

Daily 

2004-

2006 

2005-

2006 

2004-

2006 

2005-

2006 

2004-

2006 

20

2

Max 

24 hr 

avg Rat Max 

24 hr 

avg Rat 

Daily 

Max Ann Rat 

Daily 

Max Ann Rat 

24 hr 

avg A

Location 99th 99th 98th 98th 99th 98th 99th Atlanta 0.078 0.042 1.84 0.071 0.038 1.88 0.078 0.018 4.36 0.071 0.018 4.00 0.042 0.Boston 0.064 0.043 1.50 0.059 0.039 1.50 0.064 0.023 2.73 0.059 0.023 2.50 0.043 0.Chicago 0.093 0.052 1.80 0.088 0.050 1.77 0.093 0.031 3.03 0.088 0.031 2.86 0.052 0.Cleveland 0.072 0.043 1.68 0.065 0.038 1.70 0.072 0.022 3.35 0.065 0.022 3.03 0.043 0.Denver 0.086 0.050 1.73 0.077 0.046 1.68 0.086 0.020 4.22 0.077 0.020 3.78 0.050 0.El Paso 0.075 0.038 1.99 0.067 0.035 1.91 0.075 0.018 4.09 0.067 0.018 3.65 0.038 0.Las Vegas 0.039 0.013 3.04 0.037 0.012 3.10 0.039 0.005 8.65 0.037 0.005 8.21 0.013 0.Los Angeles 0.095 0.061 1.56 0.083 0.055 1.50 0.095 0.031 3.06 0.083 0.031 2.70 0.061 0.Miami 0.059 0.030 1.97 0.056 0.027 2.06 0.059 0.008 7.41 0.056 0.008 7.03 0.030 0.New York 0.093 0.060 1.55 0.083 0.056 1.48 0.093 0.032 2.90 0.083 0.032 2.60 0.060 0.Philadelphia 0.060 0.040 1.51 0.056 0.035 1.61 0.060 0.017 3.62 0.056 0.017 3.34 0.040 0.Phoenix 0.093 0.057 1.63 0.085 0.053 1.60 0.093 0.032 2.95 0.085 0.032 2.70 0.057 0.St. Louis 0.064 0.034 1.91 0.063 0.031 2.03 0.064 0.017 3.82 0.063 0.017 3.74 0.034 0.Washington DC 0.079 0.045 1.76 0.065 0.040 1.61 0.079 0.021 3.70 0.065 0.021 3.02 0.045 0.These are 14 of the 17 areas in the Draft REA; 3 areas did not meet completeness requirements: 

Detroit, Jacksonville, and Provo. 

Based on 2004-2006 data for sites that are at least 75% complete for hours in a day and days in a quarter and has all 4 qAs such, these estimates are not based on the same air quality data that would be used to determine whether an area wostandard or set of standards. These estimates can only approximate the number counties that are exceeding the given stand should be used with caution. 

2004-2006 

Daily 

2004-2006 

Daily 

2004-

2006 

2005-

2006 

2004-

2006 

2005-

2006 

2004-

2006 

20

2
Max 

24 hr 

avg Rat Max 

24 hr 

avg Rat 

Daily 

Max Ann Rat 

Daily 

Max Ann Rat 

24 hr 

avg A

Location 99th 99th 98th 98th 99th 98th 99th Detroit* 0.058 0.038 1.53 0.054 0.035 1.54 0.058 0.019 2.98 0.054 0.019 2.78 0.038 0.Detroit** 0.054 0.034 1.57 0.051 0.032 1.56 0.054 0.014 3.81 0.051 0.014 3.60 0.034 0.Jacksonville*** 0.049 0.027 1.84 0.048 0.024 1.98 0.049 0.012 4.22 0.048 0.012 4.14 0.027 0.Provo**** 0.065 0.054 1.20 0.063 0.047 1.34 0.065 0.021 3.13 0.063 0.021 3.04 0.054 0.* Detroit monitor 261630016 was complete for 2005 and 2006, 2004 was ignored in the averages. 

** Detroit monitor 261630019 was complete for 2004 and 2006, 2005 was ignored in the averages. 

*** Jacksonville was only complete for 2006. 

**** Provo was only complete for 2004 and 2005.