Using a distributed lag non-linear model, the study linked ambient PM2.5 with respiratory and cardiovascular mortality and morbidity in Ratchaburi during 2015–2019, from the exposure day through seven subsequent days. Across all ages and genders, each 10 µg/m³ increase was associated with 5.42% higher respiratory mortality at lag 0 and 2.69% higher respiratory morbidity over lag 0–6.
Key findings
- A 10 µg/m³ increase in PM2.5 was associated with 5.42% higher respiratory mortality at lag 0 (95% CI 1.85–9.12%).
- Respiratory morbidity increased by 2.69% over lag 0–6 (95% CI 1.45–3.95%).
- Cardiovascular mortality increased by 3.55% over lag 0–5 (95% CI 0.23–6.99%); the 1.85% morbidity estimate over lag 0–6 had a CI crossing zero (-0.24–3.98%).
Why this matters globally
Local evidence from outside a megacity supports warnings that account for immediate and multi-day health effects, particularly among older people. Policy should combine such evidence with multi-site studies and source attribution.
Thai researcher contribution
Sitthipong Pengjan, Sébastien Bonnet and Savitri Garivait from the Joint Graduate School of Energy and Environment at KMUTT and the Center of Excellence on Energy Technology and Environment under MHESI analysed Ratchaburi-specific health data.
Limitations to consider
This area-level observational study may misclassify personal exposure and retain seasonal, meteorological or epidemic confounding. It estimates short-term population associations, not individual risk; the cardiovascular-morbidity CI crossed zero.