Table 4.

Spearman correlation coefficients (%) between trace gaseous pollutants, particulate matter pollutants, and meteorological variables from Logan, Utah based on 1-hr summaries.^a

Pollutant/meteorological variable	NO2	NO	NOx	NOy	NOzb	O3	PM10	PM2.5	PM10-2.5	Wind speedc	Temperature	Humidity	Pressure	Mixing heightd	Total precipitatione
NO2	100	69	95	93	73	−92	75	75	66	−60	−53	34	26	−64	−14
NO		100	85	84	63	−60	69	69	65	−33	−38	7	22	−61	−14
NOx			100	98	74	−87	80	80	72	−54	−51	28	25	−70	−17
NOy				100	83	−84	88	88	79	−54	−55	24	25	−76	−22
NOzb					100	−61	94	95	82	−50	−60	12	21	−77	−31
O3						100	−64	−65	−56	59	47	−44	−21	58	4f
PM10							100	98	94	−44	−53	2f	22	−78	−28
PM2.5								100	87	−47	−57	11	20	−78	−28
PM10-2.5									100	−36	−42	−16	24	−67	−27
Wind speedc										100	49	−50	−6f	42	21
Temperature											100	−20	−57	59	36
Humidity												100	−24	−52	17
Pressure													100	−34	−17
Mixing heightd														100	4f
Total precipitatione															100

Notes. All correlations statistically significant at the 1% level, except as indicated.

^aSample size varied between 684 and 740, except for variable pairs involving wind speed or mixing height. Excluding mixing height, sample sizes involving wind speed ranged from 508 to 531. Excluding wind speed, sample sizes involving mixing height were between 273 and 286. The value of n for the wind speed/mixing height pair was 193.

^bNO_z = NO_y – NO_x

^cWind speed had lower data capture (542 of 740 possible hr or 73%).

^dMixing height suffered from poor data capture (286 of 740 possible hr or 39%).

^eMost of the hours had no precipitation (673 of 740 possible hr or 90%).

^fNot statistically significant (10% level).