Smog Master is Clovis's air quality monitoring and public alert system

Smog Master is a real-time air quality information system run by the San Joaquin Valley Air Pollution Control District. In Clovis and surrounding areas, it tracks pollution levels throughout the day and sends alerts when air quality drops to unhealthy ranges. The system measures five main pollutants: ground-level ozone, particulate matter (PM2.5 and PM10), nitrogen dioxide, sulfur dioxide, and carbon monoxide.

Clovis sits in the San Joaquin Valley, which regularly experiences some of the worst air quality in the United States, especially during summer and fall. Smog Master exists because residents need to know when breathing outdoors becomes a health risk — particularly for children, older adults, and people with asthma or heart disease. The alerts tell you what's happening right now and what to expect in the hours ahead.

Key Takeaways

  • Smog Master provides real-time air quality data for Clovis and the San Joaquin Valley, updated hourly throughout the day.
  • The system uses the Air Quality Index (AQI) scale, where higher numbers mean worse air and greater health risk.
  • You can check current conditions on the San Joaquin Valley Air Pollution Control District website or through the AirNow app.
  • Alerts are issued when air quality reaches unhealthy levels, and different groups (children, older adults, people with lung disease) face risk at different thresholds.

How the Air Quality Index scale works

Smog Master reports air quality using the Air Quality Index, or AQI. This is a standardized number from 0 to 500+ that tells you how polluted the air is and what health effects to expect. The higher the number, the worse the air and the greater the risk.

The AQI is divided into six color-coded ranges. "Good" (green, 0–50) means air quality is satisfactory and outdoor activity is safe for everyone. "Moderate" (yellow, 51–100) means air quality is acceptable, but unusually sensitive people — very young children, older adults, or people with asthma — may experience minor symptoms. "Unhealthy for Sensitive Groups" (orange, 101–150) means members of sensitive groups should limit prolonged outdoor exertion. "Unhealthy" (red, 151–200) means the general public may begin to experience health effects, and sensitive groups face serious effects. "Very Unhealthy" (purple, 201–300) means health effects are widespread. "Hazardous" (maroon, 301+) means the entire population faces serious health effects and should avoid outdoor activity.

Where to find current Clovis air quality readings

The San Joaquin Valley Air Pollution Control District publishes Smog Master data on its official website at valleyair.org. You can enter your city or zip code and see the current AQI, the dominant pollutant, and a forecast for the next few hours. The data updates hourly during daylight hours.

You can also check air quality through the AirNow app, available on iOS and Android, which pulls data from the same monitoring network. Many weather apps and services like Weather.com also display AQI data for Clovis. If you want alerts sent directly to your phone, the AirNow app lets you set notifications for when air quality reaches a level you choose — for example, you might ask to be notified whenever the AQI hits "Unhealthy for Sensitive Groups" or worse.

What to do when air quality is unhealthy

When Smog Master shows unhealthy air, the action you take depends on your age, health, and the AQI level. If you are in a sensitive group — under 18, over 65, pregnant, or have asthma, heart disease, or lung disease — you should limit outdoor activity whenever the AQI reaches orange (101–150) or higher. This means reducing strenuous exercise like running or sports, and keeping outdoor time shorter.

At red (151–200) or higher, sensitive groups should avoid outdoor exertion altogether and stay indoors with windows closed if possible. The general population should also reduce outdoor activity at these levels. At purple (201–300) or maroon (301+), everyone should stay indoors, keep windows and doors closed, and run air conditioning or air filters if available. If you do not have air conditioning, seek shelter in a public building like a library, mall, or community center.

Keep in mind that air quality can change quickly. A morning reading of "Moderate" does not mean the afternoon will stay that way — check the forecast included with the reading to see if conditions are expected to worsen.

Why Clovis air quality is often poor

The San Joaquin Valley, where Clovis is located, faces persistent air quality challenges because of geography and pollution sources. The valley is surrounded by mountains that trap air and pollutants, preventing them from dispersing. During summer and fall, heat and sunlight cause chemical reactions between vehicle emissions and industrial pollution, creating ground-level ozone — the main pollutant in the region.

Agricultural activity, diesel trucks, refineries, and vehicle traffic all contribute to the pollution. Even on days when local conditions are calm, pollution can drift into the valley from the coast or other regions. This is why Clovis sometimes experiences unhealthy air even when the city itself is not the primary source of the pollution.

Understanding the difference between ozone and particulate matter

Smog Master tracks multiple pollutants, and understanding which one is high helps you protect yourself. Ground-level ozone is created when sunlight reacts with emissions from cars and industry. It peaks in the afternoon and early evening on hot days. Ozone irritates the lungs and airways, making breathing harder, especially during exercise. If the dominant pollutant is ozone, avoid strenuous outdoor activity during peak hours (typically 2 p.m. to 7 p.m.).

Particulate matter — tiny solid particles and liquid droplets suspended in air — comes from dust, smoke, vehicle exhaust, and industrial sources. PM2.5 (particles smaller than 2.5 micrometers) is especially harmful because it can lodge deep in the lungs and enter the bloodstream. Unlike ozone, particulate matter does not have a peak time; it can be high any time of day. When particulate matter is the dominant pollutant, staying indoors with windows closed and using air filters becomes more important than timing outdoor activity.

Frequently Asked Questions

Can I trust the AQI number if it seems different from what I feel?

Yes. The AQI is based on scientific measurements from monitoring stations, not on how the air looks or feels. On hazy days, you might see visible smog but the AQI could still be in the moderate range. Conversely, you might not see obvious haze but the AQI could be unhealthy, especially for particulate matter. Trust the number and the health guidance that comes with it.

Does Smog Master predict air quality days in advance?

Smog Master provides hourly updates and a forecast for the next few hours, but not days in advance. The San Joaquin Valley Air Pollution Control District does issue longer-term forecasts (typically 24 to 48 hours out) on its website, but these are less precise than hourly readings. Check the forecast section on valleyair.org for extended outlooks.

What should I do if I have asthma and the air is unhealthy?

Stay indoors with windows closed when the AQI is orange or higher. Keep your rescue inhaler with you if you do go outside. Talk to your doctor about creating an asthma action plan that includes specific steps for poor air quality days. Some people benefit from using air purifiers indoors or wearing N95 masks if they must go outside.

Is the air quality the same everywhere in Clovis?

Air quality varies slightly across the city depending on proximity to highways, industrial areas, and local wind patterns. Smog Master reports readings from specific monitoring stations, so conditions near a busy freeway might be slightly worse than in a residential neighborhood. The AQI reported for Clovis is representative of the broader area, but hyperlocal variation exists.