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)
27
Good
San Marcos, Texas
Last updated: ... (Local time)

Good
Fine
Moderate
Poor
Very poor
Hazardous
4.76 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
21.02 μg/m³
0
55
155
255
425
605+
17.97 ppb
0
55
71
86
201
201+
0.62 ppb
0
36
76
186
605
1005+
6.30 ppb
0
54
101
361
1250
2050+
0.36 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
San Marcos, Texas
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AQI 24
Good
3.45μg/m³
PM2.5
26.16μg/m³
PM10
17.85ppb
O3
0.62ppb
SO2
7.20ppb
NO2
0.36ppm
CO
AQI 22
Good
4.41μg/m³
PM2.5
15.43μg/m³
PM10
16.57ppb
O3
0.62ppb
SO2
7.30ppb
NO2
0.36ppm
CO
AQI 16
Good
3.04μg/m³
PM2.5
12.31μg/m³
PM10
13.16ppb
O3
0.62ppb
SO2
6.14ppb
NO2
0.36ppm
CO
AQI 22
Good
3.72μg/m³
PM2.5
19.75μg/m³
PM10
14.65ppb
O3
0.62ppb
SO2
7.45ppb
NO2
0.36ppm
CO
AQI 16
Good
3.33μg/m³
PM2.5
14.27μg/m³
PM10
16.26ppb
O3
0.63ppb
SO2
7.52ppb
NO2
0.36ppm
CO
AQI 26
Good
3.64μg/m³
PM2.5
28.30μg/m³
PM10
15.75ppb
O3
0.62ppb
SO2
6.28ppb
NO2
0.36ppm
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 2026-03-07.
In the last 24 hours, the best air quality in San Marcos, Texas was observed at 08:00:00 on 2026-03-08.
As of now, the AQI in San Marcos, Texas is 27, indicating Good 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 4.762 μg/m3.
The PM10 concentration in San Marcos, Texas is 21.025 μg/m3 at the moment.
The current carbon monoxide (CO) concentration in San Marcos, Texas is 0.359 ppm.
Currently, San Marcos, Texas has a sulfur dioxide (SO2) concentration of 0.623 ppb.
The current ozone (O3) level in San Marcos, Texas at the moment is 17.974 ppm.
Nitrogen dioxide (NO2) level in San Marcos, Texas at the moment is 6.301 ppb.
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