August 10, 2022

Air Pollution Monitoring in Santa Ana, California: Pilot Study

Public Research: Case Studies

Study: Community-Engaged Use of Air Quality Sensors to Assess PM2.5 Concentrations across Disadvantaged Communities: Pilot Study in Santa Ana, CA

Research organizations:

- Department of Environmental and Occupational Health, University of California, Irvine, CA

- Madison Park Neighborhood Association, GREEN-MPNA Programs, Santa Ana, CA

- Department of Anthropology, School of Social Sciences, University of California, Irvine, CA

The study was a community–academic partnership between the University of California, Irvine, and a local GREEN-MPNA community group led by residents of Southeast Santa Ana. The community residents have been studying environmental justice and related health risks associated with air pollution.

Problem overview:

Low-income communities and communities of color, both in California and across the US, experience problems related to higher exposure to air pollution and other environmental hazards. People living in areas characterized by higher PM2.5 concentrations are more vulnerable to numerous health problems such as asthma and COVID-19.

The academic study took place in Santa Ana, California. The potential local air pollution sources are roadway traffic, aviation, and industrial activity, i.e. metal industries. Santa Ana’s 3 kmindustrial corridor is of particular concern to the local community. As a relatively high proportion (45.2%) of residents are immigrants with more than 70% of Latinx descent, the research group aimed to identify how air quality in these areas differs from others.  

Study objectives:

  1. Characterize air pollution near the industrial corridor in Santa Ana;
  2. Identify potential air pollution hotspots and emissions sources using both mapping techniques and local community knowledge;
  3. Characterize and compare air pollution within socially vulnerable areas versus those measured in less vulnerable communities within and outside of Santa Ana, so as to evaluate potential environmental inequities.

Duration and process:

During February-May 2021, a total of four air-monitoring field sampling days (one per month) were carried out during three separate times of the day: morning (7–10 a.m.), midday (12–3 p.m.), and evening (4–7 p.m.).

82 community volunteers participated in this pilot study: 70 adults and 12 youth of high school age (14 to 17 years old).

Atmotube PRO as a measurement tool:

The research supervisors chose the Atmotube PRO portable air quality monitor as they found it best suited for PM1 and PM2.5 concentration measurement, as well as temperature and humidity, compared to other tools.

They ran additional quality assurance tests by placing six pairs of Atmotube PRO monitors (12 devices total) next to one another for at least six hours each throughout the study period. Their 10-minute average PM2.5 measurements were compared.


When considering individual walking routes, those encompassing the industrial corridor were most frequently ranked the highest in terms of average PM2.5 concentrations. The routes encompassing the freeways were ranked relatively low when compared with industrial corridor  routes within a given day. This suggests that the industrial corridor is likely to be a more important source of PM2.5 than freeway traffic.

Nonetheless, PM2.5 concentrations of samples collected near freeways were on average higher than those collected in non-freeway zones (outside the industrial corridor area). This indicates  that freeway proximity may influence air pollution concentrations.

While PM2.5 concentrations exhibited regional variability, concentrations were on average below the EPA’s annual PM2.5 standard of 12 μg/m3.

The Atmotube portable air quality sensors used in this community-engaged study provided high-density environmental monitoring and helped foster greater health-related awareness and education among communities.

To see the full study, please click here.

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