Air Quality Monitors
Overview
The I-25 North Express Lanes project | Mead to Berthoud is a Regionally Significant Transportation Capacity (RS/TC) project that requires air monitoring for particulate matter during construction as part of Colorado Revised Statute 43-1-128. Air quality sensors adjacent to the project measure particulate matter concentrations during construction.
This page serves as a dashboard to provide information on project air quality monitoring. PM10 and PM2.5 monitoring will occur throughout the lifespan of the construction project.
The U.S. AQI is the Environmental Protection Agency’s index for reporting air quality.
Think of the AQI as a yardstick that runs from 0 to 500. The higher the AQI value, the greater the level of air pollution and the greater the health concern. For example, an AQI value of 50 or below represents good air quality, while an AQI value over 300 represents hazardous air quality.
For each pollutant an AQI value of 100 generally corresponds to an ambient air concentration that equals the level of the short-term national ambient air quality standard for protection of public health. AQI values at or below 100 are generally thought of as satisfactory. When AQI values are above 100, air quality is unhealthy: at first for certain sensitive groups of people, then for everyone as AQI values get higher.
The AQI is divided into six categories. Each category corresponds to a different level of health concern. For more information, visit airnow.gov/aqi/aqi-basics.
| Levels of Concern | Values of Index | Description of Air Quality |
|---|---|---|
| Good | 0 to 50 | Air quality is satisfactory, and air pollution poses little or no risk. |
| Moderate | 51 to 100 | Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution. |
| Unhealthy for Sensitive Groups | 101 to 150 | Members of sensitive groups may experience health effects. The general public is less likely to be affected. |
| Unhealthy | 151 to 200 | Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects. |
| Very Unhealthy | 201 to 300 | Health alert: The risk of health effects is increased for everyone. |
| Hazardous | 301 and higher | Health warning of emergency conditions: everyone is more likely to be affected. |
Particulate Matter (PM) describes a mixture of solid particles and liquid droplets found in the air. These particles can be comprised of materials such as vehicle exhaust, soot, dust and pollen. PM comes in many sizes and shapes, including PM2.5 and PM10. Fine particulate matter, known as PM2.5, is less than 2.5 micrometers in diameter. PM10 is particulate matter less than 10 micrometers in diameter.
Air quality sensors are located adjacent to the project in order to monitor PM10 and PM2.5 per Colorado Revised Statutes. If PM10 or PM2.5 concentrations rise above predetermined action levels in the project area, the contractor is notified, which allows the team to identify and mitigate PM levels before they reach public alert thresholds.
A public air quality alert is issued when daily average PM levels exceed an AQI of 100.
Please visit subscription.cotrip.org and follow these steps:
- Select "Subscribe to Construction Updates"
- Navigate to the Air Quality Alerts section
- Select North I-25 and Save to start receiving I-25 North Express Lanes Project Mead to Berthoud public Air Quality alerts
The particulate matter sensors used on this project are considered non-regulatory supplemental and informational monitoring sensors and not EPA Federal Reference Method (FRM) or Federal Equivalent Method (FEM) monitors. Therefore, the sensor data may not be used to determine compliance with the National Ambient Air Quality Standards (NAAQS).
Particulate matter concentration measurements from the sensors are indicative of ambient conditions nearby the sensor location and may not be indicative of air quality conditions further away from the sensor. Sensor measurements are not able to be used to explicitly determine sources of emissions.
The sensor data measurements are published prior to data validation.
Air Quality Dashboards | Mead to Berthoud
Data from each sensor is depicted on the dashboards below. On each dashboard, there are three different report pages titled Current Conditions, Measurements Today and Trending Daily AQI. Use the arrows at the bottom of the dashboard to navigate to each page.
- The Current Conditions dashboard page is based on the NowCast AQI. The NowCast AQI shows you air quality for the most current hour available by using a calculation that involves multiple hours of past data. The NowCast AQI uses longer averages during periods of stable air quality and shorter averages when air quality is changing rapidly, such as during a wildfire.
- The Measurements Today dashboard page reports the hourly average pollutant concentration data. The data on this page is refreshed every hour on the half hour mark. When the data is refreshed the previous hour's pollutant concentration value will be visible on the graph.
- The Trending Daily AQI dashboard page is based on the standard AQI in the U.S., which is EPA’s tool for communicating daily air quality. The AQI is generally based on the health-based national ambient air quality standard for each pollutant and the scientific information that supports that standard. The Trending Daily AQI calculation is run once daily. An AQI value over 100 may cause a public alert to be sent out via text or email.
Air Quality Dashboard Legend
General Acronyms
- μg/m3: Micrograms per meter cubed
- F: Fahrenheit
- MPH: Miles per hour
Wind Direction Acronyms
- N: North
- NNE: North Northeast
- NE: Northeast
- ENE: East Northeast
- E: East
- ESE: East Southeast
- SE: Southeast
- SSE: South Southeast
- S: South
- SSW: South Southwest
- SW: Southwest
- WSW: West Southwest
- W: West
- WNW: West Northwest
- NW: Northwest
- NNW: North Northwest
Note: This data is the hourly averaged concentration of PM10 and PM2.5 directly from air quality monitors. This data is not reviewed for quality control prior to being posted to this webpage. For assistance navigating the Power BI dashboard, please email [email protected] or [email protected].
