Peak Daily One-Hour Ozone Averages for April 2018

The table below lists the peak daily one-hour ozone concentrations measured in April 2018 in each community where the TREX measures ozone. Concentrations are color-highlighted based on the EPA-defined Air Quality Index colors. (See Interpreting the AQI.) All ozone measurements are in parts per billion, and are truncated to an integer number.

The values that go into this table are calculated at 3:30 am each morning. Therefore, the current day will almost always have very low hourly averages that are not truly representative of local conditions for the day. Because of this, the report does not display the current day's data.

Use the selection boxes below to customize this report. You may select a different month, a different year, a different report format, and whether or not to include time on the report. Click on the Generate Report button once you have made your selections.

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

Area	Monitoring Site	POC	April 2018																					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
CT-ME-MA-NH-RI-VT
	Sipayik TAQP-ME	1	51	46	49	45	47	52	52	47	42	43	47	58	61	51	44	48	43	36	38	44	53	1	Sipayik TAQP-ME


Area	Monitoring Site	POC	April 2018																					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
CA-NV-AZ-HI-AS-GU
	Cortina Rancheria-CA	1 ^N	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	1	Cortina Rancheria-CA
	Bishop Paiute Tribe Air-CA	1 ^N	NA	25	37	40	34	34	38	41	36	36	33	33	27	36	33	25	23	37	33	31	42	1	Bishop Paiute Tribe Air-CA
	Fort McDowell Yuma Frank-AZ	1 ^N	54	59	65	62	69	66	53	56	62	64	67	60	53	59	62	54	69	71	59	59	65	1	Fort McDowell Yuma Frank-AZ
NA - Data not available.
^N - Data from this instrument does not meet EPA quality assurance criteria and cannot be used for regulatory purposes.

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's AirNow web site.

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, TREX uses a surrogate 8-hour average based on the current hourly average.

PLEASE NOTE: This data has not been verified by the TREX 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 TREX 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.