What the study found
The study found that the Air Quality Health Index (AQHI), which combines daily levels of fine particulate matter (PM2.5), ozone (O3), and nitrogen dioxide (NO2), was more sensitive than the Air Quality Index (AQI) for short-term health-relevant risk during pandemic-altered activity patterns. It also found that high-risk AQHI levels were associated with increased respiratory and cardiovascular morbidity.
Why the authors say this matters
The authors conclude that their findings provide empirical evidence supporting Taiwan's adoption of AQHI for risk communication and for protecting vulnerable populations. They say AQHI better reflects multi-pollutant health impacts than conventional AQI systems.
What the researchers tested
The researchers analyzed PM2.5 chemical characteristics in Taichung, Taiwan, from 2020 to 2022, with a focus on polycyclic aromatic hydrocarbons (PAHs) and water-soluble ions (WSIs) in industrial and traffic areas. They also examined outpatient records from 2016 to 2022, comparing pre-pandemic, pandemic, and post-pandemic stages, and used source apportionment and lag-effect analyses.
What worked and what didn't
During pandemic restrictions, total water-soluble ion concentrations increased, largely because of non-sea-salt sulfate (nss-SO4 2−), especially in the industrial area. PAH concentrations declined during lockdowns, then rose during the warm season in the post-pandemic period to about two to three times the pandemic-stage levels; traffic-related emissions, especially diesel exhaust, were the dominant PAH source. High-risk AQHI levels (≥7) were associated with respiratory and cardiovascular morbidity, PM2.5 and NO2 showed acute and persistent risks, and O3 showed delayed inverse statistical associations.
What to keep in mind
The abstract does not describe detailed limitations beyond the study's focus on Taichung, Taiwan, and the specific pandemic period examined. The health-risk findings are based on outpatient records and statistical associations, so the summary does not state direct causation.
Key points
- AQHI, which combines PM2.5, O3, and NO2, was described as more sensitive than AQI for short-term health risk.
- High-risk AQHI levels (≥7) were associated with increased respiratory and cardiovascular morbidity.
- Pandemic restrictions coincided with higher water-soluble ions, driven mainly by non-sea-salt sulfate in the industrial area.
- PAH concentrations fell during lockdowns and later rebounded to about two to three times pandemic-stage levels in the warm season.
- Traffic-related emissions, especially diesel exhaust, were the dominant contributors to ambient PAHs.
Disclosure
- Research title:
- AQHI tracked multi-pollutant health risks better than AQI in Taiwan
- Authors:
- Po Jui Chen, Tuan Hung Ngo, Shahzada Amani Room, Yuan Cheng Hsu, Yan Cing Li, Shih Yu Pan, Ta Chih Hsiao, Yu‐Cheng Chen, Kai Hsien
- Institutions:
- China Medical University, Epigenomics (Germany), National Health Research Institutes, National Taiwan Sport University, National Taiwan University, National Yang Ming Chiao Tung University, National Yang Ming Chiao Tung University, National Yang Ming Chiao Tung University, National Yang Ming Chiao Tung University, National Yang Ming Chiao Tung University
- Publication date:
- 2026-02-23
- OpenAlex record:
- View
Get the weekly research newsletter
Stay current with scholarly research without reading academic papers — one filtered digest, every Friday.