Johnston, North Carolina Air Quality
Johnston County, North Carolina (NC)
→ Stableover 10 years
10-Year AQI Trend
The solid line shows the median AQI each year. The dashed line shows the 90th percentile (worst 10% of days).
Air Quality Day Breakdown
Number of days per year in each EPA AQI category. Green = Good (AQI 0-50), Yellow = Moderate (51-100), Orange = Unhealthy for Sensitive Groups (101-150), Red = Unhealthy or worse (151+).
Year-by-Year Data
| Year | Median AQI | 90th Pct | Max AQI | Good Days | Moderate | Unhealthy+ | Pollutant |
|---|---|---|---|---|---|---|---|
| 2023 | 44 | 60 | 115 | 240 | 124 | 1 | PM2.5 |
| 2022 | 42 | 55 | 140 | 271 | 93 | 1 | PM2.5 |
| 2021 | 44 | 60 | 97 | 240 | 125 | 0 | PM2.5 |
| 2020 | 39 | 55 | 75 | 266 | 73 | 0 | PM2.5 |
| 2019 | 46 | 60 | 87 | 224 | 139 | 0 | PM2.5 |
| 2018 | 44 | 59 | 90 | 228 | 126 | 0 | PM2.5 |
| 2017 | 46 | 61 | 93 | 216 | 149 | 0 | PM2.5 |
| 2016 | 44 | 61 | 107 | 201 | 102 | 1 | PM2.5 |
| 2015 | 41 | 57 | 93 | 211 | 51 | 0 | Ozone |
| 2014 | 42 | 57 | 84 | 212 | 51 | 0 | Ozone |
What This Means for Johnston County Residents
Johnston, North Carolina has received an Air Quality Grade of C (63/100) based on a decade of monitoring data from the EPA's air quality monitoring program. The current median AQI of 44 falls in the "Good" range.
The primary pollutant affecting this area is Fine Particulate Matter (PM2.5). Over the past 5 years, this area has averaged 0 unhealthy air quality days per year — days when sensitive groups (children, elderly, those with respiratory conditions) should limit outdoor activity. The American Lung Association's State of the Air report provides additional context on long-term health risks from air pollution exposure.
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Frequently Asked Questions
Johnston, North Carolina has a current median AQI of 44, which falls in the "Good" range. The area has received an Air Quality Grade of C (63/100) based on 10 years of EPA monitoring data.
Air quality in Johnston, North Carolina is stable over the past decade. The median AQI has changed by +2 points from 2014 to 2023.
Johnston, North Carolina averages 0 unhealthy air quality days per year over the past 5 years. On these days, sensitive groups including children, the elderly, and those with respiratory conditions should limit outdoor activity.
The primary pollutant affecting Johnston, North Carolina is Fine Particulate Matter (PM2.5). This is the dominant contributor to elevated AQI readings in the Johnston County area.
Johnston, North Carolina averages 0 unhealthy air days per year. This is relatively low, making it a reasonable choice for asthma sufferers. The primary pollutant is Fine Particulate Matter (PM2.5), which is a known asthma trigger.
With a median AQI of 44 (Good), outdoor exercise in Johnston, North Carolina is generally safe year-round. Johnston, North Carolina averages 0 days per year when athletes should move workouts indoors.