### Page 1 of 5 Generated: August 22, 2014 Source: U.S. EPA AirData <http://www.epa.gov/airdata> This report is based on monitor-level summary statistics. Air quality standards for some pollutants (PM2.5 and Pb) allow for combining data from multiple monitors into a site-level summary statistic that can be compared to the standard. In those cases, the site-level statistics may differ from the monitor-level statistics upon which this report is based. Readers are cautioned not to rank order geographic areas based on AirData reports. Air pollution levels measured at a particular monitoring site are not necessarily representative of the air quality for an entire county or urban area. AirData reports are produced from a direct query of the AQS Data Mart. The data represent the best and most recent information available to EPA from state agencies. However, some values may be absent due to incomplete reporting, and some values may change due to quality assurance activities. The AQS database is updated daily by state, local, and tribal organizations who own and submit the data. Please contact the appropriate air quality monitoring agency to report any data problems. <http://www.epa.gov/airquality/airdata/ad_contacts.html> Get detailed information about this report, including column descriptions, at http://www.epa.gov/airquality/airdata/ad_about_reports.html#mon 

# Monitor Values Report Geographic Area:Washington-Arlington-Alexandria, DC-VA-MD-WV Pollutant:Ozone Year:2012 Exceptional Events:Included (if any)

Page 1 of 5 Generated: August 22, 2014 Source: U.S. EPA AirData <http://www.epa.gov/airdata> This report is based on monitor-level summary statistics. Air quality standards for some pollutants (PM2.5 and Pb) allow for combining data from multiple monitors into a site-level summary statistic that can be compared to the standard. In those cases, the site-level statistics may differ from the monitor-level statistics upon which this report is based. Readers are cautioned not to rank order geographic areas based on AirData reports. Air pollution levels measured at a particular monitoring site are not necessarily representative of the air quality for an entire county or urban area. AirData reports are produced from a direct query of the AQS Data Mart. The data represent the best and most recent information available to EPA from state agencies. However, some values may be absent due to incomplete reporting, and some values may change due to quality assurance activities. The AQS database is updated daily by state, local, and tribal organizations who own and submit the data. Please contact the appropriate air quality monitoring agency to report any data problems. <http://www.epa.gov/airquality/airdata/ad_contacts.html> Get detailed information about this report, including column descriptions, at http://www.epa.gov/airquality/airdata/ad_about_reports.html#mon 

# Monitor Values Report Geographic Area:Washington-Arlington-Alexandria, DC-VA-MD-WV Pollutant:Ozone Year:2012 Exceptional Events:Included (if any)

Duration Description=1 HOUR

Duration Description Obs First

Max Second Max Third Max Fourth Max Actual Exc Est Exc Required Days Valid

Days Percent Days Missing

Days Exc EventsMonitor Number Site ID Address City County State EPA Region

1 HOUR 86200.102 0.097 0.09 0.089 0 0.00 214 211 99 1 None 1 110010041 420 34th Street N.E.,Washington, Dc 20019Washington District of Columbia DC 03

1 HOUR 8681 0.109 0.098 0.098 0.097 0 0.00 214 214 100 0 None 1 1100100432500 1st Street, N.W. Washington Dc Washington District of Columbia DC 03

1 HOUR 50240.125 0.105 0.094 0.092 1 1.00 214 210 98 1 None 1 240090011 350 Stafford Road Prince Frederick Calvert MD 03

1 HOUR 47720.117 0.103 0.1 0.093 0 0.00 214 194 91 0 None 1 24017001014320 Oaks Road Charlotte HallCharles MD 03

1 HOUR 47470.097 0.09 0.087 0.085 0 0.00 214 199 93 0 None 1 240210037Frederick County Airport ,180 E Airport Drive Frederick Frederick MD 03

1 HOUR 5012 0.1 0.088 0.086 0.084 0 0.00 214 211 99 0 None 1 240313001 Lathrop E. Smith Environmental Education Center, 5110 Meadowside Lane Rockville Montgomery MD 03

1 HOUR 8492 0.1 0.099 0.094 0.093 0 0.00 214 213 100 1 None 1 240330030Howard University'S Beltsville Laboratory, 12003 Old Baltimore Pike Beltsville Prince George's MD 03

1 HOUR 50040.111 0.107 0.102 0.1 0 0.00 214 208 97 1 None 1 240338003Pg County Equestrian Center, 14900 Pennsylvania Ave. Greater Upper Marlboro Prince

George's MD 03

1 HOUR 8033 0.107 0.103 0.097 0.097 0 0.00 214 189 88 5 None 1 240339991 Powder Mill Rd, Laurel, Md 20708 Not in a city Prince George's MD 03

1 HOUR 51170.102 0.101 0.1 0.098 0 0.00 214 213 100 0 None 1 510130020S 18th And Hayes St Arlington Arlington VA 03

### Page 2 of 5 Generated: August 22, 2014 Source: U.S. EPA AirData <http://www.epa.gov/airdata> This report is based on monitor-level summary statistics. Air quality standards for some pollutants (PM2.5 and Pb) allow for combining data from multiple monitors into a site-level summary statistic that can be compared to the standard. In those cases, the site-level statistics may differ from the monitor-level statistics upon which this report is based. Readers are cautioned not to rank order geographic areas based on AirData reports. Air pollution levels measured at a particular monitoring site are not necessarily representative of the air quality for an entire county or urban area. AirData reports are produced from a direct query of the AQS Data Mart. The data represent the best and most recent information available to EPA from state agencies. However, some values may be absent due to incomplete reporting, and some values may change due to quality assurance activities. The AQS database is updated daily by state, local, and tribal organizations who own and submit the data. Please contact the appropriate air quality monitoring agency to report any data problems. <http://www.epa.gov/airquality/airdata/ad_contacts.html> Get detailed information about this report, including column descriptions, at http://www.epa.gov/airquality/airdata/ad_about_reports.html#mon 

# Monitor Values Report Geographic Area:Washington-Arlington-Alexandria, DC-VA-MD-WV Pollutant:Ozone Year:2012 Exceptional Events:Included (if any)

Duration Description=1 HOUR

Duration Description Obs First

Max Second Max Third Max Fourth Max Actual Exc Est Exc Required Days Valid

Days Percent Days Missing

Days Exc EventsMonitor Number Site ID Address City County State EPA Region

1 HOUR 5061 0.125 0.106 0.099 0.099 1 1.00 214 210 98 1 None 1 510590030Sta. 46-B9, Lee Park, Telegraph Road Groveton Fairfax VA 03

1 HOUR 48250.076 0.0740.073 0.071 0 0.00 214 201 94 1 None 1 510610002Rt651 C Phelps Wildlife Management Area Not in a city Fauquier VA 03

1 HOUR 50940.092 0.086 0.083 0.081 0 0.00 214 214 100 0 None 1 51107100538-I, Broad Run High School, Ashburn Not in a city Loudoun VA 03

1 HOUR 50890.093 0.089 0.087 0.081 0 0.00 214 212 99 0 None 1 511530009James S. Long Park Not in a city Prince William VA 03

1 HOUR 5084 0.09 0.089 0.088 0.083 0 0.00 214 214 100 0 None 1 511790001 Widewater Elem. Sch., Den Rich Road Aquia Harbour Stafford VA 03

1 HOUR 33540.128 0.107 0.099 0.096 1 1.50 214 140 65 2 None 1 515100009517 N Saint Asaph St, Alexandria Health Alexandria Alexandria City VA 03

1 HOUR 15370.082 0.079 0.078 0.074 0 0.00 214 64 30 1 None 1 515100021 3200 Colvin Street Not in a city Alexandria City VA 03

### Page 3 of 5 Generated: August 22, 2014 Source: U.S. EPA AirData <http://www.epa.gov/airdata> This report is based on monitor-level summary statistics. Air quality standards for some pollutants (PM2.5 and Pb) allow for combining data from multiple monitors into a site-level summary statistic that can be compared to the standard. In those cases, the site-level statistics may differ from the monitor-level statistics upon which this report is based. Readers are cautioned not to rank order geographic areas based on AirData reports. Air pollution levels measured at a particular monitoring site are not necessarily representative of the air quality for an entire county or urban area. AirData reports are produced from a direct query of the AQS Data Mart. The data represent the best and most recent information available to EPA from state agencies. However, some values may be absent due to incomplete reporting, and some values may change due to quality assurance activities. The AQS database is updated daily by state, local, and tribal organizations who own and submit the data. Please contact the appropriate air quality monitoring agency to report any data problems. <http://www.epa.gov/airquality/airdata/ad_contacts.html> Get detailed information about this report, including column descriptions, at http://www.epa.gov/airquality/airdata/ad_about_reports.html#mon 

# Monitor Values Report Geographic Area:Washington-Arlington-Alexandria, DC-VA-MD-WV Pollutant:Ozone Year:2012 Exceptional Events:Included (if any)

Page 3 of 5 Generated: August 22, 2014 Source: U.S. EPA AirData <http://www.epa.gov/airdata> This report is based on monitor-level summary statistics. Air quality standards for some pollutants (PM2.5 and Pb) allow for combining data from multiple monitors into a site-level summary statistic that can be compared to the standard. In those cases, the site-level statistics may differ from the monitor-level statistics upon which this report is based. Readers are cautioned not to rank order geographic areas based on AirData reports. Air pollution levels measured at a particular monitoring site are not necessarily representative of the air quality for an entire county or urban area. AirData reports are produced from a direct query of the AQS Data Mart. The data represent the best and most recent information available to EPA from state agencies. However, some values may be absent due to incomplete reporting, and some values may change due to quality assurance activities. The AQS database is updated daily by state, local, and tribal organizations who own and submit the data. Please contact the appropriate air quality monitoring agency to report any data problems. <http://www.epa.gov/airquality/airdata/ad_contacts.html> Get detailed information about this report, including column descriptions, at http://www.epa.gov/airquality/airdata/ad_about_reports.html#mon 

# Monitor Values Report Geographic Area:Washington-Arlington-Alexandria, DC-VA-MD-WV Pollutant:Ozone Year:2012 Exceptional Events:Included (if any)

Duration Description=8-HR RUN AVG BEGIN HOUR

Duration Description Obs First

Max Second Max Third Max Fourth Max Actual Exc Est Exc Required Days Valid

Days Percent Days Missing

Days Exc EventsMonitor Number Site ID Address City County State EPA Region

8-HR RUN AVG BEGIN HOUR 86570.083 0.083 0.082 0.076 4 4.10 214 209 98 0 None 1 110010041 420 34th Street N.E.,Washington, Dc 20019 Washington District of Columbia DC 03

8-HR RUN AVG BEGIN HOUR 87350.098 0.088 0.087 0.087 11 11.00 214 214 100 0 None 1 1100100432500 1st Street, N.W. Washington Dc Washington District of Columbia DC 03

8-HR RUN AVG BEGIN HOUR 50300.111 0.091 0.082 0.082 11 11.20 214 210 98 0 None 1 240090011 350 Stafford Road Prince Frederick Calvert MD 03

8-HR RUN AVG BEGIN HOUR 47600.102 0.09 0.087 0.084 9 10.00 214 192 90 0 None 1 24017001014320 Oaks Road Charlotte Hall Charles MD 03

8-HR RUN AVG BEGIN HOUR 47440.095 0.085 0.081 0.078 5 5.50 214 196 92 0 None 1 240210037Frederick County Airport ,180 E Airport Drive Frederick Frederick MD 03

8-HR RUN AVG BEGIN HOUR 5031 0.087 0.077 0.074 0.073 2 2.00 214 210 98 0 None 1 240313001 Lathrop E. Smith Environmental Education Center, 5110 Meadowside Lane Rockville Montgomery MD 03

8-HR RUN AVG BEGIN HOUR 85140.091 0.085 0.08 0.079 9 9.00 214 213 100 0 None 1 240330030Howard University'S Beltsville Laboratory, 12003 Old Baltimore Pike Beltsville Prince George's MD 03

### Page 4 of 5 Generated: August 22, 2014 Source: U.S. EPA AirData <http://www.epa.gov/airdata> This report is based on monitor-level summary statistics. Air quality standards for some pollutants (PM2.5 and Pb) allow for combining data from multiple monitors into a site-level summary statistic that can be compared to the standard. In those cases, the site-level statistics may differ from the monitor-level statistics upon which this report is based. Readers are cautioned not to rank order geographic areas based on AirData reports. Air pollution levels measured at a particular monitoring site are not necessarily representative of the air quality for an entire county or urban area. AirData reports are produced from a direct query of the AQS Data Mart. The data represent the best and most recent information available to EPA from state agencies. However, some values may be absent due to incomplete reporting, and some values may change due to quality assurance activities. The AQS database is updated daily by state, local, and tribal organizations who own and submit the data. Please contact the appropriate air quality monitoring agency to report any data problems. <http://www.epa.gov/airquality/airdata/ad_contacts.html> Get detailed information about this report, including column descriptions, at http://www.epa.gov/airquality/airdata/ad_about_reports.html#mon 

# Monitor Values Report Geographic Area:Washington-Arlington-Alexandria, DC-VA-MD-WV Pollutant:Ozone Year:2012 Exceptional Events:Included (if any)

Duration Description=8-HR RUN AVG BEGIN HOUR

Duration Description Obs First

Max Second Max Third Max Fourth Max Actual Exc Est Exc Required Days Valid

Days Percent Days Missing

Days Exc EventsMonitor Number Site ID Address City County State EPA Region

8-HR RUN AVG BEGIN HOUR 5013 0.104 0.091 0.09 0.09 14 14.50 214 207 97 0 None 1 240338003Pg County Equestrian Center, 14900 Pennsylvania Ave. Greater Upper Marlboro Prince

George's MD 03

8-HR RUN AVG BEGIN HOUR 8143 0.097 0.085 0.085 0.084 15 17.10 214 188 88 0 None 1 240339991 Powder Mill Rd, Laurel, Md 20708 Not in a city Prince George's MD 03

8-HR RUN AVG BEGIN HOUR 51070.094 0.093 0.088 0.084 12 12.10 214 212 99 0 None 1 510130020S 18th And Hayes St Arlington Arlington VA 03

8-HR RUN AVG BEGIN HOUR 5051 0.106 0.097 0.096 0.084 12 12.30 214 209 98 0 None 1 510590030Sta. 46-B9, Lee Park, Telegraph Road Groveton Fairfax VA 03

8-HR RUN AVG BEGIN HOUR 48420.068 0.063 0.062 0.061 0 0.00 214 199 93 0 None 1 510610002Rt651 C Phelps Wildlife Management Area Not in a city Fauquier VA 03

8-HR RUN AVG BEGIN HOUR 50970.079 0.077 0.073 0.073 2 2.00 214 212 99 0 None 1 51107100538-I, Broad Run High School, Ashburn Not in a city Loudoun VA 03

8-HR RUN AVG BEGIN HOUR 50920.082 0.078 0.075 0.072 2 2.00 214 212 99 0 None 1 511530009James S. Long Park Not in a city Prince William VA 03

8-HR RUN AVG BEGIN HOUR 5091 0.082 0.081 0.079 0.076 4 4.00 214 212 99 0 None 1 511790001 Widewater Elem. Sch., Den Rich Road Aquia Harbour Stafford VA 03

### Page 5 of 5 Generated: August 22, 2014 Source: U.S. EPA AirData <http://www.epa.gov/airdata> This report is based on monitor-level summary statistics. Air quality standards for some pollutants (PM2.5 and Pb) allow for combining data from multiple monitors into a site-level summary statistic that can be compared to the standard. In those cases, the site-level statistics may differ from the monitor-level statistics upon which this report is based. Readers are cautioned not to rank order geographic areas based on AirData reports. Air pollution levels measured at a particular monitoring site are not necessarily representative of the air quality for an entire county or urban area. AirData reports are produced from a direct query of the AQS Data Mart. The data represent the best and most recent information available to EPA from state agencies. However, some values may be absent due to incomplete reporting, and some values may change due to quality assurance activities. The AQS database is updated daily by state, local, and tribal organizations who own and submit the data. Please contact the appropriate air quality monitoring agency to report any data problems. <http://www.epa.gov/airquality/airdata/ad_contacts.html> Get detailed information about this report, including column descriptions, at http://www.epa.gov/airquality/airdata/ad_about_reports.html#mon 

# Monitor Values Report Geographic Area:Washington-Arlington-Alexandria, DC-VA-MD-WV Pollutant:Ozone Year:2012 Exceptional Events:Included (if any)

Duration Description=8-HR RUN AVG BEGIN HOUR

Duration Description Obs First

Max Second Max Third Max Fourth Max Actual Exc Est Exc Required Days Valid

Days Percent Days Missing

Days Exc EventsMonitor Number Site ID Address City County State EPA Region

8-HR RUN AVG BEGIN HOUR 3343 0.098 0.096 0.089 0.086 7 10.90 214 138 64 0 None 1 515100009517 N Saint Asaph St, Alexandria Health Alexandria Alexandria City VA 03

8-HR RUN AVG BEGIN HOUR 15290.071 0.067 0.067 0.056 0 0.00 214 62 29 0 None 1 515100021 3200 Colvin Street Not in a city Alexandria City VA 03