Stay updated with real-time air quality in San Marcos, Texas featuring accurate data on AQI, PM2.5, PM10, O3, NO2, SO2, and CO levels. Use our interactive map and detailed forecasts to monitor pollution trends, manage health risks, and plan your daily activities with confidence.
Live AQI (Air Quality Index)
54
Moderate
San Marcos, Texas
Last updated: ... (Local time)

Good
Fine
Moderate
Poor
Very poor
Hazardous
10.65 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
47.16 μg/m³
0
55
155
255
425
605+
46.11 ppb
0
55
71
86
201
201+
0.52 ppb
0
36
76
186
605
1005+
1.51 ppb
0
54
101
361
1250
2050+
0.87 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
San Marcos, Texas
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AQI 58
Moderate
12.73μg/m³
PM2.5
52.88μg/m³
PM10
50.71ppb
O3
0.52ppb
SO2
1.52ppb
NO2
0.74ppm
CO
AQI 56
Moderate
12.20μg/m³
PM2.5
52.33μg/m³
PM10
50.15ppb
O3
0.51ppb
SO2
1.52ppb
NO2
0.73ppm
CO
AQI 56
Moderate
12.13μg/m³
PM2.5
53.88μg/m³
PM10
41.30ppb
O3
0.52ppb
SO2
1.52ppb
NO2
0.74ppm
CO
AQI 60
Moderate
14.30μg/m³
PM2.5
53.60μg/m³
PM10
49.92ppb
O3
0.52ppb
SO2
1.50ppb
NO2
0.89ppm
CO
AQI 60
Moderate
14.18μg/m³
PM2.5
52.81μg/m³
PM10
53.96ppb
O3
0.51ppb
SO2
1.50ppb
NO2
0.89ppm
CO
AQI 60
Moderate
13.59μg/m³
PM2.5
50.98μg/m³
PM10
50.61ppb
O3
0.52ppb
SO2
1.51ppb
NO2
0.88ppm
CO
Air quality and pollutant data for Texas, USA are sourced from ground-based monitors and satellites, adhering to US EPA standards. Machine learning and advanced algorithms enhance the data by incorporating local variables like traffic and population density, ensuring high accuracy and dependability.
Source: Ambee Data Sources
The air quality information for San Marcos, Texas is updated every hour for accuracy.
In the past 24 hours, the air quality in San Marcos, Texas was at its worst at 06:00:00 on 2026-07-23.
In the last 24 hours, the best air quality in San Marcos, Texas was observed at 08:00:00 on 2026-07-23.
As of now, the AQI in San Marcos, Texas is 54, indicating Moderate conditions.
San Marcos, Texas air has the highest levels of PM2.5.
Poor air quality in San Marcos, Texas means it's advisable to stay indoors and wear a mask for your protection.
PM2.5 levels in San Marcos, Texas are currently 10.653 μg/m3.
The PM10 concentration in San Marcos, Texas is 47.16 μg/m3 at the moment.
The current carbon monoxide (CO) concentration in San Marcos, Texas is 0.873 ppm.
Currently, San Marcos, Texas has a sulfur dioxide (SO2) concentration of 0.516 ppb.
The current ozone (O3) level in San Marcos, Texas at the moment is 46.109 ppm.
Nitrogen dioxide (NO2) level in San Marcos, Texas at the moment is 1.511 ppb.
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