I have not formed an opinion, but what they are saying is that:

1. The WHO has recently said that the negative health effects of air pollution are worse than previously believed.

2. People are exposed to more air pollution during warm weather.

3. Global warming causes more warm weather.

Therefore the harm air pollution causes to human health--including congenital susceptibility to heart disease--is increased by global warming.

Here's one relevant bit from the article translated by Google Translate:

“My colleague at Hasselt University, professor of environmental epidemiology Tim Nawrot, is working on a very exciting multi-year study. He tests blood samples from newborn babies, their mothers and the placenta to investigate whether there is a link with air pollution, which is greater in warm weather. The first results are clear: children exposed to more air pollution in the womb are genetically different. They will be more prone to cardiovascular disease. Climate change therefore affects the programming of babies in the womb. That problem will only get worse.”