New York

Microscopic particles from exhaust and wildfire smoke. They enter the bloodstream through the lungs, damage arterial walls, and cut nitric oxide production — the molecule your vessels use to dilate.

Nitrogen dioxide from diesel engines and industrial burning. Reacts with and depletes circulating nitric oxide directly.

UVA light releases stores of nitric oxide from skin tissue into circulation, measurably lowering blood pressure. Night and cloud cover eliminate this effect completely.

Cold causes vasoconstriction. Extreme heat raises cardiovascular demand. The circulation-friendly range is roughly 65–82°F.

Heavy air raises cardiovascular load. Your heart works harder to maintain output in humid conditions, leaving less reserve for vascular function.