How is Particulate Matter 2.5 Measured?

Particulate Matter (PM) is a serious environmental pollutant that has been linked with a variety of adverse health effects. It is important to measure PM2.5 levels in order to assess the air quality in an area and take the necessary steps to improve it.

What is PM2.5?

PM2.5 refers to tiny particles in the air that are less than 2.5 micrometers in diameter. While PM10 is a more visible, or coarse, type of PM air pollution that comes in the form of construction dust and road debris, PM2.5 is much finer, and therefore, much more insidious. It can come from a variety of sources, including power plants, vehicle exhaust, and wildfires.

PM2.5 must be monitored because it can penetrate deep into the lungs and cause serious health problems.

Read more about what particulate matter is.

How is PM2.5 Measured?

PM2.5 is typically measured with an instrument called a PM2.5 monitor or an aerosol sampler. These monitors work by drawing in air and then measuring the concentration of PM2.5 particles on a filter.

The results are typically expressed as micrograms per cubic meter of air (μg/m3). For reference, these particles are so small that they are just a fraction of the width of a human hair.

Particles can also be collected via impaction, in which air is passed through a small hole at high velocity onto a substrate. Both of these methods require laboratory analysis to determine the PM2.5 concentration.

Choosing the Right Tool for Measuring PM2.5

There are a number of different PM2.5 monitors on the market, and they vary in terms of their accuracy and cost. It is important to choose a PM2.5 monitor that is fit for the purpose it will be used for.

For example, some PM2.5 monitors are designed for use in specific locations such as schools or office buildings, while others are designed for use in larger areas such as cities. Outdoor measurement tools are typically referred to as ambient air quality monitoring stations (AQMS), while indoor tools are more widely referred to as sensors.

PM2.5 monitors can be used to measure air quality in both indoor and outdoor environments. In general, PM2.5 levels are higher outdoors than indoors. However, there are a number of factors that can affect PM2.5 levels in both environments, including weather, traffic, and industrial activity.

When choosing a PM2.5 monitor, it is important to consider the specific needs of the area that will be monitored. For example, if PM2.5 levels in an area are known to fluctuate rapidly, a PM2.5 monitor with a high refresh rate may be necessary in order to get accurate measurements8.

Why is PM2.5 Measurement Important?

High PM2.5 concentrations are associated with a higher risk of respiratory disease, and pose a greater threat to children, pregnant women, and immunocompromised people. The greater our awareness of real-time PM2.5 measurements, the more informed decisions we can make regarding the air quality around us.

Ambient Measurements

PM2.5 measurement is important because it allows us to quantify the level of air pollution in a specific area. This information can be used to take steps to improve air quality, such as implementing emissions controls or promoting the use of public transport.

PM2.5 measurement is also important for tracking trends over time and assessing the effectiveness of air quality improvement efforts. On a personal note, being aware of PM2.5 concentrations in your neighborhood can help you take precautions to avoid exposure to potentially harmful areas.

Indoor Measurements

Another large contributor to PM2.5 levels is indoor smoke from cooking or heating with the use of kerosene, fuels, biomass, and coal. These can greatly increase the risks associated with short and long-term PM2.5 exposure.

Comparing Local PM2.5 Measurements to Safety Standards

The EPA has a suggested threshold for PM2.5 concentration, which is currently at 15 micrograms per cubic meter10. After reviewing numerous health studies and environmental reports, they have concluded that this is the acceptable standard of PM2.5 measurement, ensuring that air quality does not negatively impact the overall quality of life.

Worried about your air quality?

Monitor the Particulate Matter levels around the world with our free, real-time PurpleAir Map or join PurpleAir's mission to make air quality data accessible to everyone by investing in an air quality monitor for your home. 

Together, we can be informed and make changes in our daily habits and the community to improve air quality.