The extraordinary industrial activity of the 19th century gave the coal industry further impetus and by 1819 the smoke nuisance had become so conspicuous that Parliament appointed a Com mittee to enquire how far persons using steam engines and fur naces could erect them in a manner less prejudicial to public health and comfort ; but although it was reported that evidence bore out the practicability of smoke prevention, no active steps were taken. Further Select Committees in 1843 and 1845 achieved some practical result; for sections were inserted in the Railway Clauses Act of 1845 requiring locomotives, and in the Town Improvement Clause Act of 1847 requiring factory furnaces, to consume their own smoke.
Between 1875 and 1926 English law relating to the excessive emission of smoke from industrial chimneys, with the exception of London, was administered under clauses in the Public Health Act 1875, which enacted that "any fireplace or furnace which does not, as far as practicable, consume the smoke from the combustible consumed therein . . . shall be deemed to be a nuisance," provided "that where a person is summoned before any Court in respect of a nuisance from a fireplace or furnace, the Court shall hold that no nuisance is created within the mean ing of the Act if it is satisfied that such fireplace or furnace is constructed in such a manner as to consume as far as practicable (having regard to the nature of the manufacture or trade) all smoke arising therefrom; and that such fireplace or furnace has been carefully attended to by the person having the charge thereof." It has not been customary to attempt to convict under this clause, owing to the difficulty of defining the term "prac ticable," advantage usually being taken of a further and more workable clause that "any chimney (not being the chimney of a private dwelling-house) sending forth black smoke in such quan tity as to be a nuisance, shall be deemed to be a nuisance liable to be dealt with summarily in the manner provided by the Act."
Neither of these clauses was applicable to mines or to certain specially exempted metallurgical processes such as smelting and the conversion of pig iron into wrought iron. London was covered by very similar but somewhat more severe provisions in its own Public Health (London) Act 1891, while certain modifications of the general clauses of the 1875 Act were introduced in various local Acts. Scotland also had separate legislation.
The Public Health (Smoke Abatement) Act 1926 was largely the outcome of the work of a Departmental Committee on Smoke Abatement charged to examine the existing state of the law and its administration, and to make proposals to Parliament prior to its amendment. This Act modifies previous clauses by the im portant phrase "notwithstanding that the smoke is not black smoke," although a conviction cannot be secured if the offender is able to prove that he "has used the most practical means for preventing the nuisance." Local authorities are empowered to "make by-laws regulating the emission of smoke of such colour, density or content as may be prescribed by the by-laws," and, further, to combine in carrying out their duties. Advantage of this latter provision was immediately taken in several districts. There should result a greater degree of uniformity in the definition of smoke nuisances. Concessions to metallurgical industries are retained and the Minister of Health is empowered to extend these by Provisional Order to other trades or processes. Domestic grates are also exempted, but power is given to make by-laws requiring the provision in new buildings other than private dwelling-houses of such arrangements for heating and cooking as are calculated to prevent or reduce smoke emission.
Owing to the wider use of central heating, the more recent devel opment of industry, and the greater regard for technical training, the smoke nuisance is less apparent on the Continent of Europe than in Great Britain, and other European countries have not parallel smoke legislation. Certain measures, however, both national and local, are in force. In Germany, for instance, par ticulars of projected boiler or furnace installations must be sub jected to the police authorities for examination by technical experts and advertised in order that complaints of possible damage may be submitted. In Paris the Pref et de Police has in stituted a committee to enquire into remedial measures against smoke.