Observations of atmospheric pollution throughout Britain are considered in relation to the amounts of pollution emitted through the combustion of coal. The estimated weight of ash emitted into the air and the estimate, from deposit gauges, of the ash deposited, are considered likely to agree fairly well at a figure of rather over one million tons per annum (one million tonnes/yr).On the assumption that about 1.5 million tons of smoke are blown to sea each year, it is shown that about 1.1 million tons of sulphur dioxide are blown to sea each year; the remaining 0.8 million tons of smoke and 3.9 million tons of sulphur dioxide must be deposited in Britain, irrespective of the quantities measured in deposit gauges.The average life of a smoke particle before deposition on land is probably of the order of 1–2 days; that of a molecule of sulphur dioxide is estimated with rather more certainty to be less than 12 hours.Of the chlorides collected in deposit gauges more than half, as a rule, come from the sea, and less than half from the utilization of coal; but the ratio must vary with the position of the deposit gauge relative to the sea and to industries.