7 6 



Air Pollution by Coal Smoke. 



[APRIL, 



which some thirty years ago was carrying two bullocks to the 

 acre will now carry less than one head of stock to three acres. 



In many cases the pollution of the air by coal smoke has 

 resulted in an economic loss of rent. An instance may be 

 quoted of land near one of the coal mines in the Barnsley 

 district, where the rent which in 1887 was 52s. 6d. per acre 

 was reduced in 1890 to 27s. per acre on condition that no claim 

 was made for damage from smoke pollution. In 1900 the rent 

 was again reduced to 20s. per acre, and in 1902 further reduced 

 to 10s. per acre. At the present time this land consists of little 

 more than derelict grass land, or barren arable land growing 

 practically nothing but stunted sorrel and spurrey. 



Electrification Experiments. 

 The results of experiments carried out at Garforth showed 

 that the electrification of the atmosphere brings about a 

 heavier deposition of soot particles, and that these soot 

 particles acted as nuclei of condensation for other smoke 

 products. 





Parts per 



Million. 





r~ 



Electrically 







treated. 



Untreated 



Suspended matter 



270-8 



8i-o 



Tar 



15-3 



3'8 



Acidity as H. 2 S0 4 



IQ'3 



io-6 



Sulphur as SO } 



33-2 



I5'6 



SO, 



7-2 



0-36 



Chlorine 



24-9 



103 



Nitrogen as KH S . . 



4-120 



1-481 



N,6 5 '•• .-. 



0-813 



0-493 



albuminoid ammonia 



°-434 



0-167 



Total nitrogen 



5-3^7 



2-041 



If these results generally hold good, they indicate that while 

 the electrification of plants may prove beneficial in the rural 

 districts, the process cannot be used to advantage in the 

 districts where its value might be greatest, such as the market 

 gardening districts in the neighbourhoods of the industrial 

 areas. In such areas the intensified smoke effects would more 

 than counterbalance the good effects which would otherwise 

 result from the electrical treatment. 



Summary of Conclusions. — The main detrimental effects of air 

 pollution by coal smoke upon vegetation may be summarised , 

 as follows : — 



1. The cloud of smoke blocks out the sunlight, and 

 thus reduces the available solar energy by, in some cases, 

 as much as 40 per cent. 



