Daily Maximum Eight-Hour Ozone Averages for May 2013

The table below lists the peak daily maximum eight-hour ozone concentrations measured in May 2013 in each community where the Virginia DEQ measures ozone. Concentrations that are rated Moderate or higher are color-highlighted based on the EPA-defined Air Quality Index colors. (See Interpreting the AQI.) All ozone measurements are in parts per billion.

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Month:	Year:	Report Format:	Include time:
			Include time
Highlight with AQI colors

Area	Monitoring Site	POC	May 2013																					POC	Monitoring Site
Area	Monitoring Site	POC	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	POC	Monitoring Site
Southwest
	Rural Retreat	1	45	37	42	41	45	31	45	35	46	44	42	44	51	58	66	59	53	40	34	33	38	1	Rural Retreat


Area	Monitoring Site	POC	May 2013																					POC	Monitoring Site
Area	Monitoring Site	POC	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	POC	Monitoring Site
Valley
	Albemarle High School	1	57	47	46	36	48	34	34	37	44	52	45	48	47	57	62	60	58	43	24	37	38	1	Albemarle High School
	Frederick Co. Public School Maint. Dept.	1	59	47	51	47	56	28	30	43	44	45	39	41	45	51	60	54	60	49	32	36	37	1	Frederick Co. Public School Maint. Dept.
	Luray Caverns Airport	1	60	48	49	43	52	35	35	41	47	52	45	45	49	54	63	56	58	40	32	42	40	1	Luray Caverns Airport
	Natural Bridge Station	1	50	45	42	36	46	28	32	32	42	49	38	46	47	53	61	56	46	42	22	38	34	1	Natural Bridge Station
	Harrisonburg VDOT	1	58	47	48	39	51	30	26	40	44	51	45	47	49	54	62	57	56	47	27	43	42	1	Harrisonburg VDOT


Area	Monitoring Site	POC	May 2013																					POC	Monitoring Site
Area	Monitoring Site	POC	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	POC	Monitoring Site
Blue Ridge
	Herman L. Horn Elementary School	1	50	47	42	40	48	33	39	38	48	50	38	46	49	56	64	57	50	40	31	35	47	1	Herman L. Horn Elementary School


Area	Monitoring Site	POC	May 2013																					POC	Monitoring Site
Area	Monitoring Site	POC	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	POC	Monitoring Site
Piedmont
	Shirley Plantation	1	43	39	43	37	41	32	38	32	39	NV	43	46	44	51	64	58	57	44	27	27	33	1	Shirley Plantation
	Beach Road VDOT	1	47	40	46	35	43	31	45	34	41	52	44	49	45	53	65	62	64	45	30	30	32	1	Beach Road VDOT
	Hanover	1	47	38	45	36	44	32	41	35	43	54	48	46	46	55	67	67	61	42	33	36	37	1	Hanover
	MSIC (MathScience Innovation Center)	1	48	38	44	38	43	30	43	33	41	50	44	46	45	52	65	62	65	42	34	32	34	1	MSIC (MathScience Innovation Center)


Area	Monitoring Site	POC	May 2013																					POC	Monitoring Site
Area	Monitoring Site	POC	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	POC	Monitoring Site
Tidewater
	NASA Langley Research Center	1	41	NV	43	47	47	37	43	41	48	52	46	46	48	55	66	66	62	52	36	27	33	1	NASA Langley Research Center
	Tidewater Community College	1	41	37	41	46	47	32	41	37	45	52	48	46	48	52	67	63	58	50	35	25	15	1	Tidewater Community College
	VA Tech Agricultural Research Center	1	43	41	46	43	47	35	48	43	48	53	50	47	48	54	68	66	63	48	38	30	34	1	VA Tech Agricultural Research Center


Area	Monitoring Site	POC	May 2013																					POC	Monitoring Site
Area	Monitoring Site	POC	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	POC	Monitoring Site
Northern
	Aurora Hills Visitor Center	1	52	39	43	43	50	30	31	44	39	56	39	44	45	51	63	57	67	45	32	39	42	1	Aurora Hills Visitor Center
	Fredericksburg Geomagnetic Observatory	1	51	38	46	43	49	33	35	38	42	54	43	48	47	54	65	61	58	40	29	33	35	1	Fredericksburg Geomagnetic Observatory
	Lee District Park - Fairfax County	1	54	40	45	44	49	32	29	39	39	54	38	44	46	51	62	59	67	44	33	34	37	1	Lee District Park - Fairfax County
	Sumerduck - C. Phelps Wildlife Mgmt Area	1	55	42	47	42	50	29	36	37	33	48	38	44	46	52	60	53	56	39	26	29	31	1	Sumerduck - C. Phelps Wildlife Mgmt Area
	Ashburn - Broad Run High School	1	55	42	47	44	53	29	30	42	45	50	38	44	48	52	60	55	64	45	34	37	42	1	Ashburn - Broad Run High School
	Shenandoah National Park - Big Meadows	1	NA	NA	NA	NA	NA	NV	52	51	54	53	47	47	49	58	64	63	61	53	41	43	41	1	Shenandoah National Park - Big Meadows
	Long Park - Haymarket	1	57	42	50	46	55	30	33	42	42	51	36	43	45	53	61	52	62	44	32	35	36	1	Long Park - Haymarket
	Widewater Elem. School - Widewater	1	54	40	47	47	50	35	30	40	38	50	42	47	46	53	63	58	64	39	30	34	35	1	Widewater Elem. School - Widewater
POC (Parameter Occurrence Code): a code used to correctly separate data from multiple instruments at one site.
NV - There are not enough valid eight-hour averages for this day (there must be eighteen valid eight-hour averages).
NA - Data not available.

Interpreting the AQI

Air Quality Index

Each NAAQS pollutant has a separate AQI scale, with an AQI rating of 100 corresponding to the concentration of the Federal Standard for that pollutant. Additional information about the AQI and how it can be used is available from the EPA.

Place your mouse pointer over the scale displayed above to view information about the Air Quality Index, and each of the rating levels.

The actual index calculation is different for each parameter measured and is specified by the EPA. The following table shows the various breakpoints used in calculating the AQI.

AQI Breakpoint Definitions
AQI Range	1hr Ozone in ppm	8hr Ozone in ppm
0 - 50	Not Defined	0 - 0.059
51 - 100	Not Defined	0.06 - 0.075
101 - 150	0.125 - 0.164	0.076 - 0.095
151 - 200	0.165 - 0.204	0.096 - 0.115
201 - 300	0.205 - 0.404	0.116 - 0.374
301 - 400	0.405 - 0.504	Not Defined
401 - 500	0.505 - 0.604	Not Defined
500+	Not Defined	Not Defined

The AQI for ozone is based on either the peak eight-hour running average since midnight OR the peak one-hour measurement since midnight. When calculating air quality for the current day, the Virginia DEQ uses a surrogate 8-hour average based on the current hourly average.

PLEASE NOTE: This data has not been verified by the Virginia DEQ and may change. This is the most current data, but it is not official until it has been certified by our technical staff. Data is collected from Virginia DEQ ambient monitoring sites and may include data collected by other outside agencies. This data is updated hourly. All times shown are in local standard time unless otherwise indicated.