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
10.67 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
47.87 μg/m³
0
55
155
255
425
605+
22.88 ppb
0
55
71
86
201
201+
0.64 ppb
0
36
76
186
605
1005+
6.63 ppb
0
54
101
361
1250
2050+
0.34 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
San Marcos, Texas
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AQI 52
Moderate
10.15μg/m³
PM2.5
40.78μg/m³
PM10
23.07ppb
O3
0.68ppb
SO2
5.11ppb
NO2
0.31ppm
CO
AQI 52
Moderate
10.14μg/m³
PM2.5
40.54μg/m³
PM10
23.82ppb
O3
0.68ppb
SO2
5.10ppb
NO2
0.31ppm
CO
AQI 49
Good
9.05μg/m³
PM2.5
40.93μg/m³
PM10
18.17ppb
O3
0.68ppb
SO2
5.14ppb
NO2
0.31ppm
CO
AQI 56
Moderate
11.55μg/m³
PM2.5
34.57μg/m³
PM10
21.53ppb
O3
0.68ppb
SO2
5.10ppb
NO2
0.31ppm
CO
AQI 52
Moderate
10.32μg/m³
PM2.5
40.29μg/m³
PM10
24.73ppb
O3
0.68ppb
SO2
4.84ppb
NO2
0.32ppm
CO
AQI 54
Moderate
11.34μg/m³
PM2.5
38.27μg/m³
PM10
21.77ppb
O3
0.68ppb
SO2
4.70ppb
NO2
0.31ppm
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 03:00:00 on 2026-03-09.
In the last 24 hours, the best air quality in San Marcos, Texas was observed at 07:00:00 on 2026-03-09.
As of now, the AQI in San Marcos, Texas is 52, 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 10.295 μg/m3.
The PM10 concentration in San Marcos, Texas is 45.877 μg/m3 at the moment.
The current carbon monoxide (CO) concentration in San Marcos, Texas is 0.314 ppm.
Currently, San Marcos, Texas has a sulfur dioxide (SO2) concentration of 0.677 ppb.
The current ozone (O3) level in San Marcos, Texas at the moment is 24.936 ppm.
Nitrogen dioxide (NO2) level in San Marcos, Texas at the moment is 5.11 ppb.
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