Table 32.1 - Relative natural and anthropogenic contribution (per cent) to tropospheric ozone precursor emissions in 1990

Source: RAS, 1993

Sources  COCH4 VOCsNOx
GlobalAnthropogenic 62631076
Natural 383790*24
Northern hemisphere Anthropogenic 72731684
Natural 282785* 16

Note: * Including isoprene and terpenes.