Ozone and fine exhaust particles make asthma worse

The industrial world has been so successful at dealign with smoke pollution that the avalanche of recent work showing that fine particles in the atmosphere are damaging health has come as an unwelcome surprise. Dockery and Pope published a summary of this evidence in 19941; since then more confirmatory evidence has appeared, and the conclusions have been independently validated.2 Further material appeared from Britain's Department of Health in a comprehensive review of non-biological particles and health,3 and the Department of the Environment has recommended a new standard of 50 µg/m³ for a 24 hour period for particles less than 10 microns in size (generally known as PM10).4 Achieving this new standard will set a considerable challenge for transport authorities in Europe and North America. The solutions may need radical new policies for urban transportation. Other regulatory and advisory agencies are engaged in a frenzy of activity as they consider the impact of the epidemiological evidence.

The medical evidence is …