Air Quality (AQI) & Weather in San Marcos, TX (78666)

Q: What is the primary air pollutant in San Marcos, TX?

The primary air pollutants monitored in San Marcos include Fine Particulate Matter (PM2.5), Coarse Particulate Matter (PM10), Ground-level Ozone (O3), Carbon Monoxide (CO), Nitrogen Dioxide (NO2), and Sulfur Dioxide (SO2).

Air Quality Index

Temperature

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Real-time Temp

Humidity

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Relative humidity

Wind

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Wind Speed

Pollutants

Good

Moderate

USG

Unhealthy

Very Unhealthy

Hazard

Location Map

29.88260, -97.97974

7-Day Forecast

Full Weather for San Marcos

Past 30 Days — AQI History

Health Advice

Loading recommendations...

Recommendations are indicative. Consult local advisories if you have underlying health concerns.

About Air Quality in San Marcos, TX

Get real-time updates on air quality in San Marcos (78666), including detailed metrics for key pollutants like PM2.5, PM10, Ozone (O₃), Carbon Monoxide (CO), Nitrogen Dioxide (NO₂), and Sulfur Dioxide (SO₂).

This dashboard presents live Air Quality Index (AQI) calculations alongside a 7-day weather forecast for San Marcos, TX. Monitor changing pollution levels, relative humidity, wind speeds, and temperature trends to plan safer outdoor activities for your family.

Understanding AQI Ratings

The standard US Air Quality Index (AQI) runs from 0 to 500. Higher values indicate higher levels of air pollution:

0–50 (Good): Air quality is satisfactory; minimal risk.
51–100 (Moderate): Acceptable; slight concern for sensitive people.
101–150 (USG): Sensitive groups may experience health effects.
151–200 (Unhealthy): General public may begin to feel effects.
201–300 (Very Unhealthy): Health alert; increased risk for everyone.

Air Pollution Prevention & Health Tips for San Marcos

Air quality in San Marcos, TX fluctuates based on weather patterns, traffic volume, seasonal industrial output, and atmospheric conditions.

Outdoor Mask Protection

During high PM2.5 pollution spikes (AQI > 150), standard surgical masks are insufficient. N95 or KN95 respirators are recommended for effective filtering.

Indoor Air Purifiers

Using True HEPA air purifiers inside homes and offices in San Marcos helps filter airborne dust, allergens, pollen, and dangerous fine particles.

Environmental & Demographic Profile — San Marcos, TX (78666)

The ZIP code 78666 is situated in San Marcos, located within Hays County, TX. According to US Census estimates, the 78666 postal code serves an estimated population of 87,775 residents across an area with a population density of 176.2 people per square mile. Operating under the America/Chicago timezone, local atmospheric telemetry in this area is monitored continuously via nearby regional monitoring stations.

San Marcos is categorized as a low-density or regional geographic area. Lower industrial activity generally reduces localized vehicular pollution, though ambient air quality can still be impacted by agricultural particulate matter, regional wind currents, or seasonal meteorological activity.

Geographic & Administrative Details

County: Hays County
Coordinates: 29.8826, -97.9797
Timezone: America/Chicago
Associated Regions: Hays, Guadalupe, Comal, Caldwell

Frequently Asked Questions About San Marcos Air Quality

What is the primary air pollutant in San Marcos, TX?

The primary pollutants continuously monitored in San Marcos include Fine Particulate Matter (PM2.5), Coarse Particulate Matter (PM10), Ground-level Ozone (O₃), Carbon Monoxide (CO), Nitrogen Dioxide (NO₂), and Sulfur Dioxide (SO₂).

Is it safe to exercise outdoors today in San Marcos (78666)?

Outdoor exercise safety in San Marcos depends on the real-time Air Quality Index (AQI). An AQI between 0 and 50 is ideal for all outdoor activities. If the index rises above 100, sensitive individuals should reduce prolonged outdoor exertion.

How often is the air quality data updated for ZIP code 78666?

Air quality observations and weather metrics on this page are updated in real-time using continuous telemetry from local satellite feeds and ground station monitors.