Washington Post – no paywall: “Fireworks for this year’s July Fourth celebration are expected to cause hazardous levels of pollution around the National Mall and “very unhealthy” conditions in central D.C., according to internal National Park Service documents reviewed by The Washington Post. The show, billed by the Trump administration as the largest pyrotechnic display in history, will include some 850,000 fireworks in a roughly 40-minute show expected to start at 10:30 p.m. or 11 p.m. The combustion from large fireworks displays typically causes significant pollution because it generates fine particulate matter, also known as PM2.5. These small particles can penetrate deep into the heart and lungs, causing irritation and in some cases asthma attacks and other illnesses. A draft air-quality analysis, based on the National Park Service’s modeling, states that people should “avoid prolonged exposure” to the pollution around the Mall…”