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)
71
Moderate
San Marcos, Texas
Last updated: ... (Local time)

Good
Fine
Moderate
Poor
Very poor
Hazardous
8.58 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
25.84 μg/m³
0
55
155
255
425
605+
60.76 ppb
0
55
71
86
201
201+
0.81 ppb
0
36
76
186
605
1005+
6.64 ppb
0
54
101
361
1250
2050+
0.39 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
San Marcos, Texas
Scroll To Air Quality MapLoading...
AQI 56
Moderate
12.07μg/m³
PM2.5
39.37μg/m³
PM10
55.86ppb
O3
0.83ppb
SO2
10.51ppb
NO2
0.40ppm
CO
AQI 56
Moderate
12.45μg/m³
PM2.5
50.28μg/m³
PM10
55.36ppb
O3
0.83ppb
SO2
10.54ppb
NO2
0.40ppm
CO
AQI 74
Moderate
12.53μg/m³
PM2.5
39.96μg/m³
PM10
62.35ppb
O3
0.82ppb
SO2
8.07ppb
NO2
0.39ppm
CO
AQI 58
Moderate
12.96μg/m³
PM2.5
52.72μg/m³
PM10
56.74ppb
O3
0.83ppb
SO2
7.48ppb
NO2
0.40ppm
CO
AQI 77
Moderate
13.45μg/m³
PM2.5
51.85μg/m³
PM10
62.54ppb
O3
0.88ppb
SO2
7.47ppb
NO2
0.40ppm
CO
AQI 58
Moderate
12.85μg/m³
PM2.5
56.15μg/m³
PM10
56.87ppb
O3
0.83ppb
SO2
7.99ppb
NO2
0.39ppm
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 11:00:00 on 2026-10-21.
In the last 24 hours, the best air quality in San Marcos, Texas was observed at 03:00:00 on 2026-10-22.
As of now, the AQI in San Marcos, Texas is 71, indicating Moderate conditions.
San Marcos, Texas air has the highest levels of O3.
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 8.584 μg/m3.
The PM10 concentration in San Marcos, Texas is 25.844 μg/m3 at the moment.
The current carbon monoxide (CO) concentration in San Marcos, Texas is 0.394 ppm.
Currently, San Marcos, Texas has a sulfur dioxide (SO2) concentration of 0.807 ppb.
The current ozone (O3) level in San Marcos, Texas at the moment is 60.759 ppm.
Nitrogen dioxide (NO2) level in San Marcos, Texas at the moment is 6.642 ppb.
All Rights Reserved © Ambee Inc. 2025