Houses emit more pollution than factories

Private households are one of the biggest sources of pollution such as greenhouse gases and gases causing acid rain, according to the first environmental accounts for Britain published by the Office for National Statistics, writes Diane Coyle.

Domestic heating and the private car put households at the top of the league for emissions of greenhouse gases and particulates.

The figures allocating pollution to different sectors of the economy overturn the assumption that manufacturing industry is the main culprit.

Agriculture emerges as another big polluter because of ammonia emissions.

The environmental accounts also put the value of the depletion of North Sea oil and gas at pounds 2.3bn in 1993, suggesting that national income has been overstated by that amount. North Sea reserves will last for another 40 years at 1993 rates of extraction.

The new figures also include a measure of "defensive" expenditure by industry to combat pollution, estimated at pounds 2.3bn in 1993. Chemicals, paper and publishing and food manufacturing accounted for almost half of total spending by industry on pollution control.

But the ONS has not yet decided whether this means national income is understated, because this is spending that brings the benefit of cleaner air, or whether it is overstated, because the expenditure is a burden imposed by the creation of pollutants in the first place.

The new environmental accounts, the first of several "satellites" due to be published by the ONS, do not construct a measure of "green GDP". Official statisticians argue that this would require putting judgmental monetary values on benefits such as clean air or asthma-free children.

However, the green satellite is intended to make it possible to measure the likely environmental impact of policies such as higher petrol taxes. In future it will be extended to include measures of nuclear waste and water pollution.

The project follows standards for national accounts set by the United Nations three years ago to develop better measures of economic well-being.

The environmental satellite can put values on the depletion of resources and on pollution control spending because they involve market transactions. However, the breakdown of pollution by industry and sector uses physical measures.

Electricity generation is the biggest single producer of greenhouse gases and acid rain precursors such as sulphur dioxide. But allocating electricity demand to its end-users puts households at the top of the league for both of these categories as well as "blacksmoke", the particulates in exhaust emissions.

Households accounted for 210 metric tonnes of greenhouse gases and 1,434 metric tonnes of acid rain gases in 1993, about a third and a quarter of the total respectively. They also produced a big chunk of other emissions affecting air quality such as blacksmoke and lead.