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Understanding PM levels: What is considered unhealthy and why?

In our daily lives, we often encounter terms like PM, PM2.5, or PM10, especially when discussing air pollution and its impact on health. But what exactly is PM, and why should we be concerned about its levels? In this blog, we will explore the world of particulate matter (PM) and delve into the harmful effects of high PM levels on human health.

What is PM? (Particulate Matter) 

Particulate Matter, commonly known as PM, refers to a mixture of solid particles and liquid droplets suspended in the air. These particles vary in size, composition, and origin. Sources of PM include natural processes such as dust storms, forest fires, and volcanic eruptions, as well as human activities like industrial emissions, vehicle exhaust, and construction sites.

PM is categorized based on its size, measured in micrometers (µm). The two most commonly discussed categories are PM2.5 and PM10. PM2.5 refers to particles with a diameter of 2.5 micrometers or smaller, while PM10 includes particles with a diameter of 10 micrometers or smaller. To put it into perspective, a human hair is roughly 70 micrometers in diameter, making PM particles invisible to the naked eye.

Size comparison chart of PM 

What PM level is considered unhealthy and why? 

The impact of PM on human health is directly related to its size and composition. Smaller particles, such as PM2.5, pose a greater risk as they can penetrate deep into the respiratory system and even enter the bloodstream, causing a range of adverse health effects. 

PM levels are typically measured in micrograms per cubic meter (µg/m3) of air. Various organizations, including the World Health Organization (WHO) and local environmental agencies, have established guidelines to identify healthy and unhealthy PM levels. The following are commonly recognized thresholds:

  • Moderate PM Levels (0-35 µg/m3): PM levels within this range are considered relatively safe for most individuals. However, sensitive groups, such as the elderly, children, and people with respiratory or cardiovascular diseases, may experience minor health effects if exposed for a prolonged period.

  • Unhealthy for Sensitive Groups (35-55 µg/m3): At these levels, sensitive individuals may experience increased respiratory symptoms, such as coughing, wheezing, and shortness of breath. It is advised for vulnerable individuals to reduce outdoor activities and take precautions to limit exposure.

  • Unhealthy (55-150 µg/m3): When PM levels reach this range, even healthy individuals may experience adverse health effects. Symptoms can include aggravated respiratory conditions, reduced lung function, and increased risk of respiratory infections. It is recommended to minimize outdoor exposure, especially during strenuous activities.

  • Very Unhealthy (150-250 µg/m3): PM levels in this range pose a significant risk to everyone. Even short-term exposure can lead to severe respiratory problems, exacerbation of existing conditions, and increased hospital admissions. It is crucial to stay indoors and keep windows closed, using air purifiers if available.

  • Hazardous (>250 µg/m3): PM levels exceeding this threshold are extremely dangerous and can cause immediate and severe health effects. People of all ages and health conditions are at risk, with symptoms ranging from respiratory distress to cardiovascular complications. It is crucial to stay indoors, ideally in buildings with efficient air filtration systems.

How to monitor PM levels in your home? 

In the quest for healthier indoor environments, advanced technology has emerged to aid in monitoring air quality levels. The WYND Sentry device, renowned as the most comprehensive solution for smoking and loud noise detection, goes a step further by offering constant monitoring of average PM levels in a given space. With its cutting-edge sensors, the WYND Sentry device provides real-time data on particulate matter concentrations, including PM2.5 and PM10. This allows individuals to stay informed about the air quality in their home. This innovative feature empowers individuals to take proactive measures to protect their health by minimizing exposure to high PM levels. Whether in vacation rental homes, hotel rooms, schools, or public spaces, the WYND Sentry device is a valuable tool that combines convenience, advanced technology, and health consciousness to promote a cleaner and safer indoor environment.

Image of WYND Sentry reporting smoking in a space


Particulate Matter (PM) is a major concern when it comes to air pollution and its impact on human health. PM2.5 and PM10, consisting of various particles suspended in the air, can cause respiratory and cardiovascular problems when present at high levels. Understanding the different categories of PM and the associated health risks is crucial for individuals and communities to take appropriate measures to protect themselves.

By monitoring PM levels and following guidelines set by organizations like the WHO and local environmental agencies, we can minimize exposure to unhealthy air and advocate for cleaner and safer environments. Everyone has a role to play in reducing PM emissions, whether through sustainable transportation, proper waste management, or supporting policies that promote clean energy sources. Together, we can create a healthier future by tackling the challenge of particulate matter pollution.


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