# Heatwave 1987: the Piraeus versus Athens case

## TL;DR

The 1987 heatwave had much higher mortality in Athens than Piraeus, with different air pollutants (ozone and nitric oxide) playing key roles in each city.

## Contribution

The study identifies distinct ambient parameters (ozone in Piraeus, nitric oxide in Athens) as key factors in heatwave mortality differences.

## Key findings

- The 1987 heatwave was seven times more lethal in Athens compared to Piraeus.
- Nitric oxide (NO) concentration was the dominant factor in Athens' heatwave mortality.
- Ozone was the dominant factor in Piraeus' heatwave mortality in 1987.

## Abstract

Background: Heatwaves represent the main indices of climate change, while mortality is one of the established markers of their human effects. Populations adapt to temperature variations/challenges differently for unknown reasons. Thus, heatwave evaluations should be enriched by historical context and local data, to allow better precision and prediction.

Methods: The mortality data for 1987 were collected from the Piraeus municipality registry, whereas data for Athens were obtained from literature retrieved from PUBMED. Ambient characteristics were derived from Geronikolou’s 1991 thesis and the reports of national organizations. From the death events, the odds ratio and relative risk in Athens compared to the Piraeus 1987 event were calculated. Finally, a simple neural network proposed the dominant ambient parameter of the heatwave phenomenon in each place.

Results: The 1987 heatwave was more lethal (seven-fold) in Athens than in Piraeus and was found to be dependent on nitric oxide (NO) concentration (with probability 0.999). In the case of Piraeus in 1987, ozone characterized the phenomenon.

Conclusions: The odds of dying due to a heatwave are highly dependent on lifestyle, population sensitivity to preventive measures and public health policy, while the phenomenon was mainly moderated by ozone in Piraeus in 1987, and NO in Athens irrespective of year.