Stay updated with real-time air quality in Longmont, Colorado 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)
49
Good
Longmont, Colorado
Last updated: ... (Local time)

Good
Fine
Moderate
Poor
Very poor
Hazardous
8.90 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
38.99 μg/m³
0
55
155
255
425
605+
35.51 ppb
0
55
71
86
201
201+
0.38 ppb
0
36
76
186
605
1005+
14.66 ppb
0
54
101
361
1250
2050+
0.28 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
Low
Longmont, Colorado
Longmont, Colorado
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AQI 33
Good
4.53μg/m³
PM2.5
20.51μg/m³
PM10
35.96ppb
O3
0.41ppb
SO2
22.73ppb
NO2
0.26ppm
CO
AQI 44
Good
8.08μg/m³
PM2.5
40.57μg/m³
PM10
33.95ppb
O3
0.41ppb
SO2
25.97ppb
NO2
0.26ppm
CO
AQI 31
Good
5.42μg/m³
PM2.5
32.86μg/m³
PM10
17.56ppb
O3
0.41ppb
SO2
26.59ppb
NO2
0.26ppm
CO
AQI 32
Good
4.62μg/m³
PM2.5
17.17μg/m³
PM10
35.14ppb
O3
0.41ppb
SO2
16.36ppb
NO2
0.26ppm
CO
AQI 31
Good
5.42μg/m³
PM2.5
32.86μg/m³
PM10
17.56ppb
O3
0.41ppb
SO2
26.59ppb
NO2
0.26ppm
CO
AQI 34
Good
4.57μg/m³
PM2.5
22.38μg/m³
PM10
37.49ppb
O3
0.41ppb
SO2
21.86ppb
NO2
0.27ppm
CO
Air quality measurements for Colorado, USA meet strict US EPA standards. These measurements are collected from reliable sources, including satellites and ground-based monitoring systems. Advanced algorithms and machine learning techniques are applied to the data, factoring in variables such as traffic and population density, to ensure precision and reliability.
Source: Ambee Data Sources
Air quality data for Longmont, Colorado is updated on an hourly basis.
The worst air quality in Longmont, Colorado was recorded at 05:00:00 on 2025-10-22.
The best air quality in Longmont, Colorado was recorded at 04:00:00 on 2025-10-21.
The real-time air quality index in Longmont, Colorado is 49, currently categorized as Good.
The most common pollutant in Longmont, Colorado is PM2.5.
If the air quality in Longmont, Colorado is poor, limit outdoor activities and use a mask to safeguard your health.
The measured PM2.5 levels in Longmont, Colorado at present are 8.897 μg/m3.
The current PM10 levels in Longmont, Colorado are 38.987 μg/m3.
The current carbon monoxide (CO) level in Longmont, Colorado is 0.281 ppm.
The current sulfur dioxide (SO2) levels in Longmont, Colorado are 0.378 ppb.
The current ozone (O3) levels at Longmont, Colorado is 35.51 ppm.
The current nitrogen dioxide (NO2) levels at Longmont, Colorado is 14.658 ppb.
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