Stay updated with real-time air quality in Portsmouth, New Hampshire featuring accurate data on AQI, PM2.5, PM10, O3, NO2, SO2, and CO levels. Use our interactive map and detailed forecasts to monitor pollution trends, manage health risks, and plan your daily activities with confidence.
Live AQI (Air Quality Index)
21
Good
Portsmouth, New Hampshire
Last updated: ... (Local time)

Good
Fine
Moderate
Poor
Very poor
Hazardous
0.80 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
2.04 μg/m³
0
55
155
255
425
605+
23.06 ppb
0
55
71
86
201
201+
1.09 ppb
0
36
76
186
605
1005+
1.80 ppb
0
54
101
361
1250
2050+
0.20 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
Portsmouth, New Hampshire
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AQI 21
Good
0.80μg/m³
PM2.5
2.06μg/m³
PM10
23.08ppb
O3
1.09ppb
SO2
1.80ppb
NO2
0.20ppm
CO
AQI 21
Good
0.79μg/m³
PM2.5
2.35μg/m³
PM10
22.83ppb
O3
0.99ppb
SO2
1.83ppb
NO2
0.20ppm
CO
AQI 20
Good
0.64μg/m³
PM2.5
1.87μg/m³
PM10
21.84ppb
O3
0.90ppb
SO2
1.78ppb
NO2
0.19ppm
CO
AQI 21
Good
0.57μg/m³
PM2.5
2.21μg/m³
PM10
22.54ppb
O3
0.94ppb
SO2
3.06ppb
NO2
0.20ppm
CO
AQI 20
Good
0.60μg/m³
PM2.5
2.49μg/m³
PM10
22.36ppb
O3
0.88ppb
SO2
1.80ppb
NO2
0.19ppm
CO
AQI 21
Good
0.48μg/m³
PM2.5
2.20μg/m³
PM10
22.88ppb
O3
0.90ppb
SO2
2.98ppb
NO2
0.19ppm
CO
Air quality and pollutant data for New Hampshire, USA are sourced from ground-based monitors and satellites, adhering to US EPA standards. Machine learning and advanced algorithms enhance the data by incorporating local variables like traffic and population density, ensuring high accuracy and dependability.
Source: Ambee Data Sources
The air quality information for Portsmouth, New Hampshire is updated every hour for accuracy.
In the past 24 hours, the air quality in Portsmouth, New Hampshire was at its worst at 11:00:00 on 2026-09-27.
In the last 24 hours, the best air quality in Portsmouth, New Hampshire was observed at 09:00:00 on 2026-09-28.
As of now, the AQI in Portsmouth, New Hampshire is 21, indicating Good conditions.
Portsmouth, New Hampshire air has the highest levels of O3.
Poor air quality in Portsmouth, New Hampshire means it's advisable to stay indoors and wear a mask for your protection.
PM2.5 levels in Portsmouth, New Hampshire are currently 0.799 μg/m3.
The PM10 concentration in Portsmouth, New Hampshire is 2.045 μg/m3 at the moment.
The current carbon monoxide (CO) concentration in Portsmouth, New Hampshire is 0.196 ppm.
Currently, Portsmouth, New Hampshire has a sulfur dioxide (SO2) concentration of 1.092 ppb.
The current ozone (O3) level in Portsmouth, New Hampshire at the moment is 23.06 ppm.
Nitrogen dioxide (NO2) level in Portsmouth, New Hampshire at the moment is 1.797 ppb.
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