C644 Data by Site by Date (all parameters)

Use this form to retrieve hourly data collected at Longview C19/A127/C644. Although this is the most current data, it is not considered official until it has been certified by the technical staff. This information is updated hourly.

This web page provides the most current hourly averaged data available. Our convention for time-tagging data is the beginning of each hour. For example, values shown for the noon hour are based on measurements taken from noon to 1:00 p.m. The noon average will not be calculated until after 1:00 p.m. The noon average will then be available on our external server from 1:15 p.m. to 1:30 p.m. This results in an apparent one-hour time lag in the data. We also present our data in Local Standard Time for each measuring site. For most of Texas this is Central Standard Time. During Daylight Savings, this introduces another apparent one-hour time lag in the data.

Use the controls below to select a different date or time format. Click on the Generate Report button once you have made your selections.

Click on the Plot Data button once the tabular report has been generated to open a separate window containing data plots.

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Month:	Day:	Year:	Time Format:

Green underline for validated data

The table below contains hourly averages for all the pollutants and meteorological conditions measured at Longview C19/A127/C644 for Sunday, April 28, 2024. All times shown are in CST.

Parameter Measured	Morning												Afternoon									Parameter Measured	POC
Parameter Measured	Mid	1:00	2:00	3:00	4:00	5:00	6:00	7:00	8:00	9:00	10:00	11:00	Noon	1:00	2:00	3:00	4:00	5:00	6:00	7:00	8:00	Parameter Measured	POC
Sulfur Dioxide	-0.2	-0.4	NEG	NEG	NEG	NEG	NEG	NEG	NEG	NEG	NEG	NEG	NEG	1.0	NEG	NEG	NEG	NEG	NEG	FEW	NA	Sulfur Dioxide	3 ^R ^MDL
Nitric Oxide	-0.2	CAL	CAL	CAL	CAL	-0.0	0.0	-0.0	0.2	0.1	0.0	0.0	0.0	0.4	0.0	0.0	-0.1	0.2	-0.0	FEW	NA	Nitric Oxide	1 ^MDL
Nitrogen Dioxide	-0.6	CAL	CAL	CAL	CAL	NEG	NEG	NEG	NEG	NEG	NEG	NEG	NEG	NEG	NEG	NEG	NEG	NEG	NEG	FEW	NA	Nitrogen Dioxide	1 ^R ^MDL
Oxides of Nitrogen	-0.8	CAL	CAL	CAL	CAL	NEG	NEG	NEG	NEG	NEG	NEG	NEG	NEG	-4.8	NEG	NEG	NEG	-4.7	NEG	FEW	NA	Oxides of Nitrogen	1 ^MDL
Ozone	42	40	43	42	40	39	31	26	31	33	37	37	36	38	39	36	33	51	50	FEW	NA	Ozone	2 ^R ^MDL
Wind Speed	8.7	7.1	5.5	5.2	4.2	1.8	1.3	1.9	3.3	3.5	4.2	4.2	4.6	7.2	7.4	4.9	7.3	5.4	5.6	FEW	NA	Wind Speed	1
Wind Direction	169	167	164	152	159	198	171	143	119	163	165	171	147	145	170	159	213	181	136	FEW	NA	Wind Direction	1
Resultant Wind Speed	8.2	6.6	5.1	4.8	3.8	0.9	0.3	1.6	3.1	3.0	3.7	3.9	3.9	6.4	6.8	4.6	4.2	1.4	4.5	FEW	NA	Resultant Wind Speed	1
Resultant Wind Direction	170	166	165	153	157	160	130	130	115	164	165	172	138	144	171	158	267	201	136	FEW	NA	Resultant Wind Direction	1
Maximum Wind Gust	26.3	22.3	17.7	16.3	15.4	9.6	3.6	5.9	7.3	12.3	11.7	16.3	17.1	23.3	27.2	16.5	22.8	16.1	19.0	FEW	NA	Maximum Wind Gust	1
Std. Dev. Wind Direction	21	21	21	22	25	59	71	31	21	30	28	23	32	27	22	21	52	70	36	FEW	NA	Std. Dev. Wind Direction	1
Outdoor Temperature	74.9	74.1	73.3	72.7	71.9	72.0	71.7	71.7	73.4	75.1	76.3	77.3	77.6	78.7	80.4	78.4	74.3	63.3	62.8	FEW	NA	Outdoor Temperature	1
Solar Radiation	0.000	0.000	0.000	0.000	0.000	0.002	0.021	0.119	0.319	0.424	0.548	0.449	0.507	0.695	0.567	0.088	0.007	0.002	0.000	FEW	NA	Solar Radiation	1
Precipitation	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.29	0.78	0.07	FEW	NA	Precipitation	1
Parameter Measured	Mid	1:00	2:00	3:00	4:00	5:00	6:00	7:00	8:00	9:00	10:00	11:00	Noon	1:00	2:00	3:00	4:00	5:00	6:00	7:00	8:00	Parameter Measured	POC
Parameter Measured	Morning												Afternoon									Parameter Measured	POC
	Maximum values for each parameter are bold within the table. Minimum values are *bold italic*.
	^R - Data from this instrument meets EPA quality assurance criteria for regulatory purposes.

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

Following EPA reporting guidelines, negative values may be displayed in our hourly criteria air quality data, down to the negative of the EPA listed Method Detection Limit (MDL) for the particular instrument that made the measurements. The reported concentrations can be negative due to zero drift in the electronic instrument output, data logger channel, or calibration adjustments to the data. Prior to 1/1/2013, slightly negative values were automatically set to zero.

Texas Commission on Environmental Quality

Longview C19/A127/C644 Data by Site by Date (all parameters)