PM10 — Coarse Particulate Matter
PM10 refers to airborne particles with a diameter of 10 micrometers or less — roughly the width of a human hair. While less penetrating than PM2.5, PM10 still causes significant respiratory harm and is a key component of dust storms, construction pollution, and road dust.
What is PM10?
PM10 particles include dust, pollen, mold spores, and coarse industrial particles. Unlike PM2.5 (which penetrates the deepest lung tissues), PM10 is mostly trapped in the nose, throat, and upper airways. However, at high concentrations it causes significant inflammation and respiratory symptoms.
PM10 is measured as a 24-hour average in μg/m³. The US EPA AQI system grades PM10 concentrations up to 604 μg/m³. In dusty regions (Rajasthan, Sahara, Arabian Peninsula), PM10 spikes during dust storms can exceed 2,000 μg/m³ — well above the AQI scale.
PM10 vs PM2.5
| Feature | PM2.5 | PM10 |
|---|---|---|
| Particle size | ≤2.5 μm | ≤10 μm |
| Penetration depth | Deep lung / bloodstream | Nose, throat, upper airways |
| Main sources | Combustion, vehicle exhaust | Dust, construction, roads |
| WHO annual limit | 5 μg/m³ | 15 μg/m³ |
| US EPA 24-hr standard | 35 μg/m³ | 150 μg/m³ |
| Health risk per μg/m³ | Higher | Lower |
| Seasonal pattern | Winter worst (combustion) | Summer/dry worst (dust) |
Sources of PM10
- Road dust — resuspension by vehicles (major urban source)
- Construction and demolition — cement, sand, demolition debris
- Desert and agricultural dust — wind erosion of bare soil
- Industrial facilities — quarries, cement plants, steel mills
- Biomass burning — crop residue, wildfires, wood burning
- Natural sources — pollen, sea spray, volcanic ash
- Mining activities — coal, stone, and mineral dust
Health Effects of PM10
Respiratory effects
- Coughing, sneezing, nasal congestion
- Worsening of asthma
- Bronchitis and upper respiratory infections
- Eye and throat irritation
Longer-term exposure
- Reduced lung function over time
- Increased risk of respiratory infections
- Aggravated cardiovascular disease
- Allergy and asthma sensitisation (pollen PM10)
PM10 AQI Breakpoints (US EPA)
Based on 24-hour average concentration in μg/m³.
India's PM10 Problem
India's NAAQS PM10 limit is 60 μg/m³ (annual) — 4× higher than WHO's 15 μg/m³. Road dust alone accounts for an estimated 30–40% of PM10 in Indian cities, per CPCB. Delhi's PM10 routinely exceeds 300 μg/m³ in winter and during dust storms.
Rajasthan and Gujarat face severe PM10 from Thar Desert dust storms (May–June), when 24-hour PM10 averages can exceed 800 μg/m³ in cities like Jodhpur and Bikaner.
Protection Tips for High PM10
- During dust storms, stay indoors and seal window gaps with wet cloth or tape
- Use surgical or N95 masks when PM10 is very high (dust storm conditions)
- Water roads and construction sites — reduces PM10 resuspension
- Check if your air purifier filters PM10 (HEPA filters capture particles down to 0.3 μm)
- After dust storm events, wipe surfaces indoors — settled PM10 can resuspend