What do the air quality sensors measure and what don’t they measure?
The Los Angeles Unified Know Your Air Network consists of 200 Clarity Node-S devices that measure fine particulate matter, known as PM2.5 (i.e., the concentration of particles in the air with diameters of 2.5 microns or less). There are several types of air pollution, including greenhouse gases, smog (also known as ground-level ozone), smog precursors, and toxic air contaminants (also referred to as hazardous air pollutants). PM2.5 is one of many so-called “criteria air pollutants,” which mainly consist of smog precursors. The Los Angeles Unified sensors do not measure greenhouse gases, such as carbon dioxide (CO2), toxic air contaminants, or non-PM2.5 criteria air pollutants, such as oxides of nitrogen (NOx) or sulfur dioxide (SO2).
What are the health problems associated with PM2.5 exposure?
Researchers have found that prolonged exposure to PM2.5 air pollution to be associated with a variety of adverse health impacts including aggravated asthma, decreased lung function, irritation of the airways, coughing, difficulty breathing, irregular heartbeat, heart attacks, and premature death for people with heart or lung disease.
Will a short-term spike in PM2.5 cause health problems?
Monitoring data can show short-term spikes of PM2.5 of a few minutes. Health-based PM2.5 air quality exposure standards consider exposure rates averaged over one hour to one year. Regulators have not established health-based standards for exposure periods of less than one hour. Those with pre-existing health conditions, the very young, and the elderly tend to be most vulnerable to the adverse health impacts of exposure to PM2.5. Air quality can change slowly or rapidly depending upon the weather, wind direction, time of day, inversion layer conditions, and other factors. Given the variability in air quality conditions, it is important to be aware but also prudent in how to respond in different situations. In general, it is important to minimize exposure to PM2.5 air pollution at all times, however, it is most important to take precautionary measures when PM2.5 levels are especially high and air quality regulators, such as the South Coast Air Quality Management District, have issued alerts.
What should I do if I see high readings?
If you notice high readings of fine particulate matter (PM2.5) or the Air Quality Index (AQI), please refer to the AQI guide above. Also refer to OEHS' Air Quality, Weather and Wildfire Advisory Procedures Reference Guide (REF-886.4). Note that, in response to high levels of air pollution, principals have the authority to restrict outdoor activities, but only the Superintendent has the authority to close a school.
