Particulate Matter (PM2.5/PM10) Health Calculator

Enter your PM2.5 or PM10 concentration (µg/m³), your daily exposure hours, and sensitivity level to get your Air Quality Index (AQI), health category, estimated cigarette equivalent, and personalized health guidance. The Particulate Matter Health Calculator converts raw pollutant concentrations into meaningful health impact estimates for both general and sensitive populations.

µg/m³

Enter the 24-hour average concentration in micrograms per cubic meter.

hrs/day

How many hours per day are you exposed to this air quality?

Sensitive groups experience health effects at lower AQI levels.

m³

Enter room volume to estimate indoor particulate load (optional).

m³/hr

Airflow or ventilation rate of the space (optional). Used to estimate air changes per hour.

Results

Air Quality Index (AQI)

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AQI Health Category

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Cigarette Equivalent (per day)

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Adjusted Exposure Risk Score

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Air Changes per Hour (ACH)

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Who is at Risk

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Health Effects

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Cautionary Statement

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AQI vs. Health Threshold Levels

Results Table

Frequently Asked Questions

What is the difference between PM2.5 and PM10?

PM2.5 refers to fine particulate matter with a diameter of 2.5 micrometers or less, which can penetrate deep into the lungs and even enter the bloodstream. PM10 includes coarser particles up to 10 micrometers in diameter. PM2.5 is generally considered more dangerous because of its ability to reach deeper into the respiratory system.

How is the Air Quality Index (AQI) calculated from a concentration?

The AQI is calculated using EPA breakpoint tables that map pollutant concentrations to an index value from 0 to 500. A linear interpolation formula is applied within each breakpoint range: AQI = ((AQI_high - AQI_low) / (Conc_high - Conc_low)) × (Concentration - Conc_low) + AQI_low. This tool uses the official US EPA AQI breakpoints for PM2.5 and PM10.

What does the cigarette equivalent mean in air quality terms?

The cigarette equivalent is an intuitive way to understand PM2.5 exposure. Research suggests that breathing air with a PM2.5 AQI of 22 for one full day is roughly equivalent to smoking one cigarette. This calculator adjusts that estimate based on your actual hours of exposure to give a relatable health impact figure.

Who are considered sensitive groups for particulate matter exposure?

Sensitive groups include people with heart or lung disease, older adults, children, and people with diabetes. These individuals can experience health effects at lower AQI levels than the general population. Very sensitive individuals — such as those with asthma, COPD, or cardiovascular conditions — face elevated risk even at 'Moderate' AQI levels.

What AQI level is considered safe for outdoor activity?

An AQI of 0–50 is 'Good' and poses little to no risk for outdoor activity. An AQI of 51–100 is 'Moderate' and is acceptable for most people, though unusually sensitive individuals should consider limiting prolonged exertion. Above 100, sensitive groups should begin reducing outdoor exposure, and above 150 everyone should limit strenuous outdoor activity.

What is Air Changes per Hour (ACH) and why does it matter?

ACH (Air Changes per Hour) measures how many times the total air volume of a room is replaced in one hour. It is calculated as airflow rate divided by room volume. Higher ACH values mean more ventilation, which helps dilute indoor pollutant concentrations faster. A minimum of 4–6 ACH is recommended for spaces with occupants.

How does daily exposure time affect my health risk?

The standard AQI is based on 24-hour average exposure. If you are only exposed for part of the day, your actual inhaled dose is proportionally lower. This calculator adjusts the risk score based on your entered exposure hours to give you a more personalized estimate of health impact compared to a full 24-hour exposure scenario.

Why does the EPA use 24-hour averages for PM2.5 and PM10?

The 24-hour averaging period is used because short-term peak concentrations can be misleading, while sustained exposure over a full day better reflects real-world health risk. The EPA's National Ambient Air Quality Standards (NAAQS) set the 24-hour PM2.5 standard at 35 µg/m³ and the annual standard at 12 µg/m³ to protect public health.

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