Air Monitoring Q&A

Learn more about the IVAN Air Monitoring network and data below.

About IVAN Air Monitoring


1. What is IVAN Air Monitoring?

IVAN Air Monitoring is a network of 40 air monitors located throughout Imperial County. As of September 2016, all but 7 of these monitors have been installed. These monitors measure current levels of particulate matter air pollution (PM2.5 and PM10). The air quality measurements are displayed on this website.

This network was developed in response to the community residents’ concerns about air quality and their desire for more neighborhood-level data. The network was designed with significant input and decision-making from community residents, while incorporating technical priorities to ensure scientific integrity. To our knowledge, it is the first community-designed network of its size in the world.

2. How is IVAN Air Monitoring different from government networks?

Air monitors operated by regulatory government agencies are used to measure air quality to see if pollution levels meet federal and state air quality standards. There are currently 5 government monitors in Imperial County used for regulation.

Our network measures air quality at additional locations throughout the county. Our monitors are different from government monitors and cannot be used to assess if air pollution levels are within legal limits. But they provide other important information. For example, community members can find out current air quality at a specific location and see recommended actions to protect health. Air quality data from our monitors can also be used for research and to inform activities aimed at improving health and the environment for Imperial County communities. Learn more about how data from our monitors differ from government monitoring data.

3. How were community members engaged in setting up this network?

Our network has had strong community engagement throughout its development. Comite Civico del Valle (CCV), a community-based organization with over 30 years of service in Imperial County, is a leading partner in developing and maintaining the network.

To ensure that the network was responsive to community needs, all activities are guided by a Community Steering Committee of community leaders and concerned residents from Imperial County. Additionally, community residents from over 11 cities and towns throughout the county participated in a two-day process to identify and prioritize where to place the air monitors. Finally, CCV staff received technical training to install, operate, and conduct maintenance on the monitors.

4. Who is responsible for this network?

The network was developed through a partnership between Comite Civico del Valle (CCV), the California Environmental Health Tracking Program (CEHTP), and University of Washington School of Public Health (UW). After the original funding ends in early 2018, the network will be continue to operate under the stewardship of CCV, with CEHTP and UW participating in associated research activities.

5. Who funded this network?

The network was developed through a 4-year project (from 2013-2017) funded by the National Institute of Environmental Health Sciences, grant number 5R01ES022722-03. Learn more about the project. Find out how you can support the continuation of this effort.

6. How is IVAN Air Monitoring related to IVAN?

IVAN (Identifying Violations Affecting Neighborhoods) is an environmental justice monitoring and reporting network that currently operates in seven California communities. The IVAN Air Monitoring is an initiative of IVAN, meaning that any community in the IVAN network can leverage infrastructure developed for the IVAN Air Monitoring to display air monitoring data, should they wish to initiate their own community air monitoring network.

7. How do I find air quality information on this website?

This website provides different ways to quickly view current air quality at each monitor, as well as ways to view more detailed data.

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, and how this will benefit the residents of Imperial County.

6. Where can I get other air quality data for Imperial County?

Air quality data for Imperial County is also available at the following websites:

7. What are Community Air-Quality Levels (CALs)?

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. The CALs uses the same 4-color scheme as school flag programs within Imperial County.

*Sensitive groups include children, teens, older adults, pregnant women, and people with heart, lung, or other chronic diseases

8. Can I compare Community Air-Quality Levels (CALs) to the Air Quality Index (AQI)?

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. This also aligns with the categories used by school flag programs in Imperial County.

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. Comite Civico del Valle 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.

Air quality and health


1. What is particulate matter?

Particulate matter (PM) pollution consists of solid and liquid particles in the air. Particles can consist of materials such as dust, dirt, soot, smoke, salt, acids, and metals. Particles can vary in size, and the smallest particles are of greatest health concern.


Image from EPA Particulate Matter Basics webpage

IVAN Air Monitoring reports on two categories of particles called PM10 and PM2.5. PM10 are particles that are less than 10 micrometers (µm) across (about seven times thinner than a human hair). PM2.5 are particles that are 2.5 micrometers or smaller, and these are also included in PM10.

We are concerned about PM10 and PM2.5 because they can be inhaled deep into the lungs and have been shown to harm health. Particles bigger than 10 micrometers can irritate your eyes, nose and throat, but do not usually reach your lungs.

2. How does short-term exposure to particulate matter affect health?

Short-term exposure to particulate matter (PM) pollution can most strongly affect people with heart or lung diseases, people with other serious health issues, and pregnant women.

If you have a lung disease, such as asthma: Being exposed to PM pollution for short periods of time like hours or a few days can make lung disease worse, cause asthma attacks, cause bronchitis, and make it easier to get respiratory infections. If PM levels are high:

  • You may not be able to breathe as deeply or strongly as normal
  • You may cough more, have chest pain, wheeze, feel like you can’t catch your breath, and be tired more than usual
  • Follow your asthma management plan if you have asthma

If you have a heart disease: Being exposed to PM pollution for short periods of time like hours or a few days can cause irregular heartbeat or heart attacks. If PM levels are high:

  • Serious problems-such as a heart attack- can happen in a short period of time without any warning signs. If you think you are having a heart attack, call 9-1-1 immediately.
  • Symptoms like chest pain or tightness, fast heartbeat, feeling out of breath, and feeling tired more than usual may be signs of a serious problem. If you have any of these symptoms, follow your doctor’s advice and contact your doctor if they last longer than usual or get worse.

If you are pregnant: Short-term exposure to PM among pregnant women has been associated with giving birth too early and having babies that are too small. Pregnant women should try to reduce exposure to high levels of PM as much as possible.

Short-term exposure to PM has also been linked with premature death, usually in people who already have a serious health problem like lung or heart disease. Healthy children and adults usually do not have serious problems from short-term exposure to PM. They may have minor problems, like a scratchy throat or scratchy eyes when PM levels are elevated.

3. How does long-term exposure to particulate matter affect health?

Long-term particulate matter (PM) exposure has been associated with heart and lung problems. Being exposed to PM pollution for more than a year is linked to problems like:

  • Breathing problems
  • Reduced lung function
  • Chronic bronchitis
  • Heart disease
  • Lung cancer

These problems may lead to more hospital stays, more emergency department visits, and even premature death. Sensitive people such as older adults, people with diseases like asthma or congestive heart disease, and children are more likely to be affected by contact with PM.

4. How can I reduce my exposure to particulate matter?

Be aware of the air quality around you and take appropriate action when levels of pollution are unhealthy. Check this website to see the Community Air-Quality Level (CAL) for the community air monitors closest to you and follow the suggested heath recommendations. Sign up to receive alerts when air quality is unhealthy at monitors located nearby to where you and your family live, work, learn, and play. We also recommend that you check the regional air quality and sign up for alerts from the government regulatory air monitoring network, as this will provide different information.

When particulate matter (PM) levels in the air are very high, everyone can reduce their exposure by spending less time outdoors and reducing physical activity levels (e.g. walking instead of running). You can also plan your daily activities to reduce exposure to PM. For example, exercise away from roads, highways, or other sources of PM, especially if you are in a group at high risk of having health problems from PM pollution.

5. Where does particulate matter come from?

Particulate matter (PM) comes from a variety of sources. According to the California Air Resources Board, the major sources of PM10 in urban and rural areas include:

  • Motor vehicles
  • Dust from construction, landfills, and agriculture
  • Wildfires and brush/waste burning
  • Industrial sources
  • Windblown dust from open lands
  • Wood burning stoves and fireplaces

In Imperial County, PM sources of concern include dust from the Salton Sea, agricultural production including feed lots, vehicle traffic near the border crossing and on unpaved roads, and the burning of trash and agricultural biomass.

PM also forms when gases emitted from motor vehicles and industry undergo chemical reactions in the atmosphere. This is called secondary particulate matter.

Technical information


1. What kind of monitors do you use?

We use a light-scattering particle counter manufactured by Dylos (Dylos 1700), which has been modified by Dylos to include four size bins (>0.5 µm, >1 µm, >2.5 µm and >10 µm). We further customized the monitor to enable wireless Internet connectivity and measurement of temperature and humidity. The monitor is enclosed in a protective shelter that does not inhibit measurements. The monitors are light weight (around 1 kg) and much less costly than federal reference monitors.

Dylos 1700 air quality monitor

2. How do the monitors work?

In contrast to government regulatory monitors that measure particle mass, the Dylos is a light-scattering particle counter. The number of particles in the air is measured by the amount of light that is redirected by each particle when passing through the detection area of the particle counter. This information, along with the temperature and humidity, is transmitted to the study servers in real-time through a wireless connection and then converted into a CAL.

3. How well do the monitors work?

We have evaluated the performance of the Dylos monitor by installing it next to a Beta Attenuation Monitor (BAM) in Calexico, operated by the California Air Resources Board (CARB). This allows us to directly compare data from the Dylos with data collected for state regulatory and air quality planning purposes. We found good correlation (~0.9) between our monitor’s 24-hour PM2.5 particle counts and CARB’s 24-hour BAM PM2.5 particle mass concentrations.

We have found similar correlations comparing Dylos data against data from a co-located Tapered Element Oscillating Microbalance (TEOM) PM instrument operated by the Imperial Irrigation District (IID) in the northern part of Imperial County.

Finally, the South Coast Air Quality Management District has done an independent evaluation of the Dylos and found very good agreement (R2=0.8) between the Dylos and a Federal Equivalent Monitor.

4. How are the PM concentrations and Community Air-Quality Levels calculated?

Step 1: Convert from counts to mass: The particle counts from the Dylos are converted to particle mass using an algorithm developed from data obtained from the comparison of the Dylos to federal equivalent monitors when co-located. This conversion takes into account relative humidity.

Step 2: Calculate concentrations: The particle mass results (in µg/m3) are averaged using the U.S. EPA NowCast method. The NowCast method produces a value for PM10 and PM2.5, which is an average of the previous 12 hours. If the air quality that day is stable, then the hours are weighted more evenly (approaching a 12‐hour average). If the air quality that day is changing, then recent hours are weighted more heavily (approaching an average of the most recent 3‐hours).

Step 3: Convert to Community Air-Quality Level: The resulting NowCast value (in µg/m3) is then converted to the Community Air-Quality Level (CAL) using the U.S. EPA Air Quality Index calculation method. CALs are categorized into 4 categories: green/low risk (0-50), yellow/moderate risk (51-100), orange/unhealthy for sensitive groups (101-150), and red/unhealthy (above 150). The 30-day and 90-day summary statistics for CALs are calculated using 24-hour AQIs.

5. How did you decide where to put the monitors?

The Community Steering Committee (CSC) identified 11 priority communities in Imperial County in which to place monitors. Over 45 residents from those communities participated in a two-day process to identify potential monitoring sites, collect data on these locations, and select their top choices. Except for a few sites that declined participation or did not meet technical criteria, we were able to place a monitor in at least one priority site per community.

After analyzing the data from these initial 20 monitors, we identified locations where additional air quality data was needed in order to fill in gaps in the monitoring network. Working with the CSC, we identified sites within these areas and are installing more monitors to complete the network.

Monitors at Torres-Martinez Reservation, State Park Road near Parkside Drive (in North Shore) and Oaxaca and Calle Villahermosa (in Mexicali) were added to the network with separate funding from the California Department of Public Health.

6. Where can I get more information about the technical/research aspects of this project?

To learn more about the technical/research aspects of this project, please contact the California Environmental Health Tracking Program.

Getting involved


1. How can I become involved in IVAN Air Monitoring?

An important and unique aspect of this network is that it is designed and operated by community members. There are many ways to become involved in the operation of the monitoring network and the use of its data, and we welcome your participation. Please contact Comite Civico del Valle for more information.

2. How can I get a monitor set up near me?

IVAN Air Monitoring was designed to be flexible and can easily be expanded to include additional air monitors within Imperial County. The only requirements are that (1) funds are provided to purchase, install, and maintain the monitor and (2) there is a suitable place to install the monitor at the desired location Please contact Comite Civico del Valle for more information.

3. How can I sponsor a monitor?

Sponsoring an air monitor is a great way to support community health in Imperial County while increasing the visibility of your business or organization. Please contact Comite Civico del Valle for more information.

Other information and resources


1. Who is responsible for regulating air quality?

At the federal level, the U.S. Environmental Protection Agency (EPA) is responsible for regulating air quality. Under the Clean Air Act, EPA limits how much of a pollutant, including particulate matter (PM), can be in the air. These limits or standards are called the National Ambient Air Quality Standards and are intended to protect public health and the environment. The Clean Air Act allows states to adopt more stringent air quality standards than the federal outdoor air standards. California has set PM standards that are more protective of public health than the national standards.

The California Air Resources Board (ARB) is responsible for regulating air quality in California and monitors the regulatory activities of California’s local air districts. To monitor PM and other air pollutants, ARB uses a network of more than 250 air monitors in California. ARB operates some air quality monitors directly, while others are operated by local authorities, private contractors, and the National Park Service. The data collected by these government monitors are used to determine which areas meet state and national air quality standards.

The Imperial County Air Pollution Control District is one of 35 local air districts in California. Local air districts have primary responsibility for controlling air pollution from stationary sources.

2. Who can I contact if there is an air pollution problem near me?

Contact the Imperial County Air Pollution Control District (APCD) at (442) 265-1800 as soon as you notice a problem. Their website lists what information to provide in order to support their investigations. It also describes what to expect when you submit a complaint.

After contacting the APCD, we recommend that you also submit a record of the problem here on IVAN Imperial, including a note that APCD has been contacted. This ensures that the Environmental Justice Task Force- a group of community and government representatives that meet monthly to review and take action on reports submitted through IVAN Imperial- is aware of the complaint and that the complaint is documented on the IVAN Imperial website.

3. Where can I get more information about air pollution?

The California Air Resources Board and the Environmental Protection Agency websites have extensive information about air pollution.

4. How can I set up a monitoring network in my own community?

Setting up a community monitoring network requires resources, expertise, community participation, and a number of other considerations. Because of their existing infrastructure, IVAN communities are particularly well-suited to leverage the web platform, community engagement protocols, and best practices developed through our project. The team behind the IVAN Air Monitoring may be able to provide guidance or assistance to other communities who are interested in setting up their own community air monitoring network. Please contact Comite Civico del Valle for more information.

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