Tag Archives: ozone forecasts

Understanding Ground-level Ozone Forecasts

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South Carolina has had two forecasted Code Orange Ozone Action Days since Ground-level Ozone forecasting season began on April 1st of this year. A Code Orange Ozone Action Day means that atmospheric conditions will likely produce concentrations of ground level ozone air pollution that may be unhealthy for sensitive groups, which includes people with lung disease, older adults, and children.   

Ozone typically forms with highest concentrations on warm, hot, sunny days with light wind speeds, which allows more of the pollutant to form and accumulate. Forecasting ground-level ozone concentrations is an educated prediction based on certain weather conditions and emissions. DHEC has a team of experienced meteorologists on staff that review weather and air quality information daily to produce a next-day ozone forecast, which is posted on DHEC’s own ozone website and U.S. EPA’s AIRNow website. 

Knowing the Ground-level Ozone Forecast ahead of time allows you to make plans and adjust your schedule and activities for the next day. Sensitive groups should reduce prolonged or heavy outdoor exertion, take more breaks, and do less intense activities, especially during afternoon and early evening hours when ozone concentrations are typically highest. 

Knowing the Ground-level Ozone Forecastahead of time also allows you to make informed decisions that can help reduce air pollution and decrease ground-level ozone by:    

  1. Refueling your car after 6:00 PM and don’t top off your tank  
  2. Using electric powered lawn equipment  
  3. Avoiding driving during peak traffic hours  
  4. Combining trips when you drive  
  5. Telecommuting (work from home) if possible
  6. Taking your lunch to work  

Sign up to receive forecasts via emails, texts or tweets (customized to fit your style) using EPA’s free EnviroFlash service at www.enviroflash.info.  
For additional information about ozone and air quality, click here.   

When Yellow means “Go”

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By: Renee Madden, Bureau of Air Quality

Last summer, I received a call from my daughter who was concerned because she had heard that the Air Quality Index (also known as the AQI) expected a Yellow flag day. Since I work with air quality data, she wanted to know if it was safe to take my 3-year-old granddaughter outside to play or was it dangerous?

I understand her concern. We live in a State that enjoys clean air. In fact, as the graph below shows, the average ozone design value has fallen over the last 18 years and has been below the National Ambient Air Quality Standard since 2010.

BAQ-table-1

So, what’s the deal with all of the colors? As you all know, the AQI is a color-coded air quality guide that lets people know how healthy the air is expected to be – kind of like an air quality shortcut. Each color is associated with a certain level of ozone in the air that lets people know the level of pollution. The Green flag and the Yellow flag are the first two colors that occur in the AQI when the ozone is below the Standard and the air is healthy for normal activities. The Green flag means it’s a Great day and the Yellow flag means it’s a Good day. I know-the color Yellow usually means caution. But, the Yellow flag in air quality means that the air is acceptable except for a small number of people that are unusually sensitive to air pollutants and may need to take some precautions. For those people, it is important to know if there are any pollutants in the air. But, for most of the general population, the Yellow flag means it is safe to go outside and play. So, don’t be scared away by seeing the Yellow flag. This is one time that “Yellow” means, “Go, play and have fun!”

Another statement that I often hear is there seems to be more Yellow flag days now than before-and that’s right! But how can that be if the air quality is better than it was 10 years ago? Good question! The answer is-(drum-roll please)-when the air standards were lowered in 2015, they also change the AQI numbers. To be a Green day in 2008, the ozone level could be up to 0.059 parts per million (ppm). Now, it can only be up to 0.054 ppm. Also, in 2008, the Yellow flag started when the ozone level was 0.060 ppm and went up to 0.075 ppm. Now the Yellow flag starts when the ozone level is 0.055 ppm and goes up to 0.070 ppm (see Table and Graphs below).

AQI Category AQI Index 2008 ppm 2015 ppm
Good 0-50 0.000-0.059 0.000-0.054
Moderate 51-100 0.060-0.075 0.055-0.070
Unhealthy for Sensitive Groups 101-150 0.076-0.095 0.071-0.085
Unhealthy 151-200 0.096-0.115 0.086-0.105

BAQ-table-2

So, before 2015, we DID have more Green flag days.

BAQ-table-3

Now, we see more Yellow flag days. But remember, Yellow flag days are good days to be outside, too!

 

Cough…sneeze…and wheeze

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By Jim Beasley

ozone

Some of us suffer more than others this time of year; allergies, coughing, sneezing, and running nose. But once allergy season subsides, many of us still have breathing difficulties. You might feel irritation in your throat, coughing- even wheezing. Whether you realize it or not, it could be due to ground-level ozone.

Ground-level ozone is one of the biggest parts of smog, and it’s usually worse in the summer months. When ground-level ozone is high, you might experience some of those breathing problems.

To help keep you aware of the health dangers associated with ozone, we recently began issuing daily ozone forecasts. Ozone is most likely to affect children, those of us with asthma or other respiratory problems, and adults who work or exercise outside. To help you better understand ground-level ozone, we recently filmed the following video with DHEC Environmental Health Manager Jack Porter.


Paying close attention to DHEC’s daily ozone forecast can help you have a healthier spring and summer. To get the latest ground-level ozone forecast, go to:

Learn more about what you can do to help reduce ozone, at http://www.scdhec.gov/ozone/HowtoHelpReduceOzone/. ​