Stay updated with real-time air quality in Castle Rock, 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)
35
Good
Castle Rock, Colorado
Last updated: ... (Local time)

Good
Fine
Moderate
Poor
Very poor
Hazardous
1.76 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
8.97 μg/m³
0
55
155
255
425
605+
38.35 ppb
0
55
71
86
201
201+
0.45 ppb
0
36
76
186
605
1005+
10.07 ppb
0
54
101
361
1250
2050+
0.18 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
Castle Rock, Colorado
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AQI 35
Good
1.67μg/m³
PM2.5
10.73μg/m³
PM10
37.65ppb
O3
0.47ppb
SO2
10.19ppb
NO2
0.20ppm
CO
AQI 36
Good
1.97μg/m³
PM2.5
9.60μg/m³
PM10
39.34ppb
O3
0.47ppb
SO2
10.11ppb
NO2
0.18ppm
CO
AQI 37
Good
1.95μg/m³
PM2.5
9.57μg/m³
PM10
40.10ppb
O3
0.47ppb
SO2
10.15ppb
NO2
0.18ppm
CO
AQI 34
Good
1.75μg/m³
PM2.5
11.08μg/m³
PM10
37.41ppb
O3
0.47ppb
SO2
10.23ppb
NO2
0.20ppm
CO
AQI 34
Good
1.73μg/m³
PM2.5
9.14μg/m³
PM10
37.41ppb
O3
0.47ppb
SO2
9.99ppb
NO2
0.20ppm
CO
AQI 34
Good
1.77μg/m³
PM2.5
10.96μg/m³
PM10
37.33ppb
O3
0.47ppb
SO2
10.21ppb
NO2
0.20ppm
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 Castle Rock, Colorado is updated on an hourly basis.
The worst air quality in Castle Rock, Colorado was recorded at 11:00:00 on 2026-03-08.
The best air quality in Castle Rock, Colorado was recorded at 04:00:00 on 2026-03-09.
The real-time air quality index in Castle Rock, Colorado is 35, currently categorized as Good.
The most common pollutant in Castle Rock, Colorado is O3.
If the air quality in Castle Rock, Colorado is poor, limit outdoor activities and use a mask to safeguard your health.
The measured PM2.5 levels in Castle Rock, Colorado at present are 1.761 μg/m3.
The current PM10 levels in Castle Rock, Colorado are 8.974 μg/m3.
The current carbon monoxide (CO) level in Castle Rock, Colorado is 0.181 ppm.
The current sulfur dioxide (SO2) levels in Castle Rock, Colorado are 0.446 ppb.
The current ozone (O3) levels at Castle Rock, Colorado is 38.355 ppm.
The current nitrogen dioxide (NO2) levels at Castle Rock, Colorado is 10.074 ppb.
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