How to check smog and air quality near you right now

The fastest way to see current smog and air quality in your area is to visit AirNow.gov, run by the U.S. Environmental Protection Agency. Enter your zip code and you get a color-coded map showing the Air Quality Index (AQI) for your location and nearby areas. Green means good air; yellow means moderate; orange, red, and purple mean increasingly unhealthy conditions. The site updates hourly.

Your phone's weather app often includes an air quality reading too — check the details section. If you want alerts sent to you automatically, read the official AirNow app or turn on notifications in your phone's built-in weather service. Both will notify you when air quality drops below a level you choose.

Local news stations also report air quality during weather forecasts, and your state's environmental agency maintains its own air quality website with regional breakdowns. Search "[your state] air quality" to find it.

Key Takeaways

  • AirNow.gov shows real-time air quality by zip code and updates every hour, with color codes that tell you whether the air is safe to breathe.
  • The Air Quality Index (AQI) ranges from green (good) to purple (hazardous), and each level comes with health guidance for sensitive groups and the general public.
  • You can set up automatic alerts on your phone through the AirNow app or your weather app so you know when smog reaches unhealthy levels.
  • State environmental agencies and local news also report air quality, and some cities send text or email alerts to residents during poor air days.

Understanding the Air Quality Index and what the colors mean

The Air Quality Index is a number from 0 to 500 that measures how clean or polluted the air is. Each number range gets a color and a health message. Green (0–50) means air quality is good and outdoor activity is safe for everyone. Yellow (51–100) means air quality is acceptable, but sensitive groups — children, older adults, and people with heart or lung disease — should limit prolonged outdoor exertion.

Orange (101–150) means members of sensitive groups should avoid outdoor activity, and the general public may start to experience symptoms. Red (151–200) means everyone should reduce outdoor activity. Purple (201–300) and maroon (301+) mean air quality is very unhealthy or hazardous; most people should stay indoors, and sensitive groups face serious health risk.

The index measures five main pollutants: ground-level ozone, particle pollution (PM2.5 and PM10), nitrogen dioxide, sulfur dioxide, and carbon monoxide. Smog is usually ground-level ozone or particle pollution, both of which irritate airways and worsen asthma and heart disease.

Where smog comes from and why it happens near you

Smog forms when sunlight reacts with emissions from cars, factories, power plants, and other sources. This process takes time, so smog often builds up during the afternoon and early evening on hot, still days. If your area is surrounded by mountains or has stagnant air patterns, pollution gets trapped and concentrations rise.

Some regions have chronic smog problems because of geography, climate, or industrial activity. Southern California, the Central Valley in California, and areas around major cities often see regular smog alerts. Other regions experience smog only during heat waves or wildfire season. Checking your local air quality regularly helps you know what to expect in your specific area.

Wildfire smoke also shows up as poor air quality on the AQI, even if it is not smog in the traditional sense. During fire season, smoke can travel hundreds of miles and affect air quality far from the fire itself.

Setting up alerts so you know when air quality drops

The AirNow app lets you set a threshold — for example, "notify me when AQI reaches orange" — and sends you a push notification when that level is reached in your zip code. You can monitor multiple locations if you work or spend time in different areas. The app is free and works on iPhone and Android.

Many state environmental agencies also offer email or text alerts. Search "[your state] air quality alerts" to find the sign-up page. Some cities, especially those with frequent smog, automatically text residents when air quality becomes unhealthy. Check your city or county health department website to see if this service is available where you live.

Weather apps like Weather.com, AccuWeather, and the built-in Apple Weather app all show AQI data. Turn on notifications in the app settings so you get alerted when conditions change. This is useful if you already check weather regularly and do not want to read another app.

What to do on high smog days

On orange, red, or purple air quality days, sensitive groups should stay indoors or limit time outside. If you must go out, wear an N95 or P100 mask — regular surgical masks do not filter smog effectively. Keep windows closed and run your air conditioner on recirculate mode so outside air does not enter your home.

If you have asthma or heart disease, have your rescue inhaler or medications with you and avoid strenuous outdoor activity. Children and older adults should also reduce exertion. Even healthy people may experience coughing, throat irritation, or shortness of breath on very poor air days.

Check the AirNow forecast to see if air quality is expected to improve the next day. Sometimes waiting a few hours or until the next morning makes outdoor activity safer. Smog often clears overnight or early in the morning before the sun heats the air again.

Finding detailed air quality information for your specific location

AirNow.gov shows not just your zip code but a map of the surrounding region, so you can see which pollutants are highest and which areas nearby have better or worse air. Click on individual monitoring stations to see hour-by-hour readings and forecasts for the next few days.

Your state's environmental agency website usually has more technical detail — historical data, which industries or sources are contributing to pollution, and long-term trends. This information is useful if you are deciding whether to move to an area or want to understand why smog is worse some seasons than others.

If you live near a major highway, airport, or industrial facility, local air quality can be worse than the regional average. Some neighborhoods have their own air monitors, and community groups sometimes run independent monitors and post results online. Search "[your neighborhood] air quality" to see if local data is available.

Frequently Asked Questions

Is the air quality reading on my phone accurate?

Phone weather apps pull data from the same EPA monitors that power AirNow.gov, so the numbers are accurate. However, the reading reflects the nearest monitoring station, which may be several miles away. Local conditions near your home can differ, especially if you live near a highway or industrial area. For the most precise picture, check AirNow.gov and look at the map to see which monitor is closest to you.

Can I wear a regular mask to protect myself from smog?

No. Surgical masks and cloth masks do not filter smog particles effectively. You need an N95 or P100 respirator mask, which you can buy at hardware stores or pharmacies. Make sure it fits snugly around your nose and mouth. Masks work best for short trips outside; staying indoors is more protective on very poor air days.

Why is air quality worse on some days than others?

Smog builds up when the sun is strong, temperatures are high, and air is still or stagnant. Windy days or cooler weather usually clear smog. Wildfire smoke, traffic patterns, and industrial activity also affect daily air quality. Checking the forecast on AirNow.gov shows you when conditions are expected to improve.

Does air purifier help with smog?

Yes, if it has a HEPA filter. HEPA filters remove fine particles that make up smog. Run the purifier in the room where you spend the most time, keep windows and doors closed, and make sure the filter is new or recently replaced. A purifier is most useful indoors; it does not protect you when you are outside.

How far away can wildfire smoke travel?

Wildfire smoke can travel hundreds of miles and affect air quality for days or weeks. Smoke from fires in California has reached the East Coast. If you see an unusual spike in AQI and no local source, check news reports — a distant fire may be the cause. The smoke usually clears once the fire is contained or wind patterns shift.