Salem — Pollution Health Impact
394 days of CPCB data (2022–2024), translated through WHO 2021, Berkeley Earth and EPIC AQLI methods. Based on CPCB station data, 2016–present.
Tamil Nadu · Live Salem AQI →
Living in Salem is the population-level health-equivalent of smoking 1.9 cigarettes a day — roughly 711 cigarettes a year. On average, that chronic exposure shortens life expectancy by about 3.7 years per resident.
Cigarette-equivalence (Berkeley Earth 2015) and life-years lost (EPIC AQLI) are peer-reviewed communication heuristics, not clinical diagnoses. Full sources linked on the methodology page.
Headline impact numbers
Cigarettes/day by year
Annual average cigarette-equivalent.
Clean-air days (NAQI ≤ 50) by year
Days when NAQI stayed in the “Good” band.
Which WHO tier did Salem meet?
24-hour PM2.5 compliance vs WHO 2021 targets.
- AQG6 days (1.5%)
- IT-471 days (18.0%)
- IT-372 days (18.3%)
- IT-2112 days (28.4%)
- IT-1128 days (32.5%)
- Above IT-15 days (1.3%)
WHO AQG (15) · IT-4 (25) · IT-3 (37.5) · IT-2 (50) · IT-1 (75) µg/m³ (24-hour PM2.5).
Life-years lost, by disease
Applying WHO's global attribution (68/14/14/4) to Salem's 3.7 year estimate.
- Heart + stroke: 2.5y
- COPD: 0.5y
- Child ALRI: 0.5y
- Lung cancer: 0.1y
Worst and best months
Drill into full monthly pattern on the seasonal Salem page →
High-risk days for vulnerable residents
- Days above WHO IT-3 (37.5 µg/m³) — pregnancy & infant risk elevated
- 245 (62.2%)
- Days above WHO IT-1 (75 µg/m³) — high risk for children under 5
- 5 (1.3%)
Source: WHO 2021 AQG interim-target risk framework; WHO 2024 ambient-air fact sheet identifies children under 5 and pregnant residents as the most vulnerable groups.
How Salem compares to nearby cities
- Similar exposureBhilai2.1 cigs/day · 4.1 y lost · +0.2 vs Salem
- Similar exposureHaldia2.1 cigs/day · 4.1 y lost · +0.2 vs Salem
- Cleaner peerKolār1.9 cigs/day · 3.7 y lost · -0.0 vs Salem
- Dirtier peerPerundurai2.0 cigs/day · 3.8 y lost · +0.0 vs Salem
What the numbers say
Overview
Living in Salem carries a daily PM2.5 dose that Berkeley Earth compares to 1.9 cigarettes a day. Over a year, residents absorb the equivalent of 711 cigarettes.
The data story
Using the Air Quality Life Index coefficient from EPIC at the University of Chicago, that long-run exposure reduces average life expectancy by roughly 3.7 years per resident. Of the 394 days on record, only 6 (1.5%) met the WHO 24-hour guideline of 15 µg/m³, while 5 days (1.3%) were above the loosest WHO Interim Target-1 (75 µg/m³).
Why this pattern
Seasonality matters: April is Salem's worst month (2.4 cigs/day equivalent) and September is the best (1.3 cigs/day). Per WHO's 2024 attribution, 68% of PM2.5-attributable deaths globally come from ischaemic heart disease and stroke, 14% from COPD, 14% from acute lower-respiratory infections in children under 5, and 4% from lung cancer.
What to do with this
These numbers are communication heuristics, not a clinical diagnosis — but they make the stakes legible. Low-cost actions stack: check 24-hour PM2.5 daily, wear an N95 in winter mornings, and run a HEPA purifier indoors during peak months. Pregnant residents and children under 5 are most at risk (WHO 2024) and benefit most from clean-air interventions on the 245 days (62.2%) when PM2.5 sits above WHO IT-3 (37.5 µg/m³).