About the data
1. What kind of air quality data can I get here?
The main purpose of the website is to provide the current Community Air-Quality Level (CAL) at each monitor location within the community air monitoring network. The CAL is an estimate of the particulate matter air quality at that location and is linked to health recommendations. The CAL reported for each monitor is updated every 5 minutes to reflect current conditions.
Each monitor has a detailed data webpage that provides more information about what air quality is usually like at that location. For example, for each location, you can see the average air quality for the past 24 hours, past 30 days, and past 90 days. Air quality data are provided as CALs and as particulate matter (PM) concentrations. The data on this website are automatically reported from the monitors and have not been verified or validated, so should be considered preliminary and used with discretion.
2. Are these data validated?
The monitors have undergone validity checks under both lab and field conditions, and our network has quality control checks in place. Additionally, the monitors used by our network perform well in comparison to government monitors and in laboratory studies. However, the data on this website have not been additionally verified or validated. Therefore, the data should be considered preliminary and used with discretion.
3. What can I do with this information?
Data from IVAN Air Monitoring can be used in a variety of ways, including:
- Find out the current air quality at one of the many monitor locations
- Take action as needed to reduce air pollution exposure for yourself and your loved ones
- Examine how particulate matter (PM) air pollution varies within the county
Data from IVAN Air Monitoring cannot be used to determine if air quality standards are being met. Only data from government regulatory monitors can be used to determine if air quality standards are being met.
4. What does it mean if the data are different from government data?
The air monitors used for IVAN Air Monitoring are different from those used by the government for air quality regulation and measure particulate matter (PM) pollution differently. While our monitors have been shown to perform very similarly to government monitors when located next to each other, they will not produce the exact same measurements. Government regulatory monitors are considered to be the most reliable, yet their very high cost and large size make their use in a community air monitoring network unfeasible.
Aside from differences between the monitors themselves, there are a number of other reasons that data from IVAN Air Monitoring may differ from the government regulatory network, such as:
- Air quality can vary within short distances, so data from the larger number of community monitors may measure and show these differences better than the relatively few government monitors.
- Government monitors may measure other air pollutants besides PM, such as ozone, which may influence the overall air quality levels reported for these monitors. The community monitors used in Imperial only measure PM.
- While we do our best to ensure that the community monitors are functioning, from time to time a community monitor may require maintenance or stop reporting data.
- IVAN Air Monitoring reports data as Community Air-Quality Levels (CALs), which are slightly different from the Air Quality Index (AQI) reported by government monitors.
We recommend that users of IVAN Air Monitoring also look at the regional air quality reported by the government network.
5. Can I get the raw data from the monitors?
For data requests, please email the project team’s scientific staff describing what data you would like, how you plan to use it.
6. Where can I get other air quality data for Bayview Hunters Point and San Francisco?
Air quality data for Bayview Hunters Point and San Francisco is also available at the following websites:
Community Air-Quality Levels (CALs) are used to describe air quality in terms of how harmful the level of particulate matter (PM) pollution in the air is to human health. The CALs are calculated for each monitor based on current concentrations, with the number and category updated on this website every 5 minutes. There are 4 CAL categories, each with an associated color and health recommendation.
*Sensitive groups include children, teens, older adults, pregnant women, and people with heart, lung, or other chronic diseases
The Community Air-Quality Levels (CALs) on our website and the Air Quality Index (AQI) used by government agencies both provide information about the general air quality levels and their risk to populations.
However, there are some differences to be aware of. While our CALs are calculated using the same method as the AQI, the air monitoring data come from a different type of monitor that performs slightly differently.
Furthermore, CALs do not contain categories beyond the unhealthy/red category, since we recommend that everyone take precaution when air pollution reaches that level of risk.
We recommend that users also pay attention to government-reported air quality when examining community air monitoring data from this website, though there are important reasons why these data may differ. When in doubt, we recommend taking precaution and action based on the highest of the air quality readings that you are comparing.
9. How are the data produced?
The monitors send air quality data over the internet to our servers. After quality control, the data are converted into air quality measurements, which are then displayed on this website. Learn about the monitors themselves, validation studies, calculation methods, and more under technical information.
10. What does it mean if a monitor is offline?
That means that data from the monitor are not being reported to the website. This can happen
for several reasons. The monitor may have gotten disconnected from the internet and needs to
be reconnected. Or, the monitor may require routine maintenance or may need to be
replaced. www.bvhp-ivan.org/air staff and project scientists get automatic notifications if a
monitor stops reporting data or if the data look unusual. They then take steps to make sure
monitors are working correctly and reporting data to the website.