Highlights• Appraisal of the previous work in the use of tropical soils in low cost, energy efficient housing development.• It established CEBs as sustainable building materials for a sustainable environment.• Identification of lateritic soils as suitable material in the production of CEBs.• Established the importance of parent rock material (its type and mineralogy) in strength and durability of CEBs.• Discouraging the common practice of firing clay bricks for the sake of sustainable environment. AbstractLateritic soils have been described as highly weathered tropical or sub-tropical residual soils with varying proportions of particle sizes ranging from clay size to gravel, usually coated with sesquioxide rich concretions. It is sometimes referred to as brick earth based on its use. The use of laterite and lateritic soils have been found to promote the realization of decent housing and bridging the housing deficit, especially in Africa.The author has attempted to review available information on the recent trends in building bricks and housing development with the aim of identifying a suitable soil material that will meet the present challenge of sustaining the environment without costing too much and maintaining a high standard of strength, durability and aesthetics. A critical review of laterite and lateritic soils from a geological point of view indicated these soils to be one of the best natural materials used in the production of compressed earth bricks. Lateritic soils are mostly well graded, comprising both cohesive (silt and clay) and cohesionless (sands and gravels) soil fraction, it contains sesquioxides and clay minerals which are very useful in the natural binding process as well as in the presence of most chemical binders.Compressed earth bricks are mainly composed of raw earth materials (soil) with their cohesion due principally to the clay fraction present in both humid and dry states. CEB's promote building in a 'sustainable' way and offers a good prospect to using our resources in an efficient manner while creating dwellings that improve human health, well-being and preserving a better environment, with an affordable and natural alternative.

Lateritic soils which have been described as highly weathered tropical or sub-tropical residual soils, were studied with an attempt to establish its suitability or otherwise as sustainable material in building bricks and housing development that will meet the present challenge of sustaining the environment without costing too much and maintaining a high standard of strength, durability and aesthetics. Index properties of the tested lateritic soils revealed them as mostly well-graded, comprising both cohesive (silt and clay) and cohesionless (sand and gravel) soil fraction. The geotechnical analyses on the studied lateritic soil revealed a strong compressive strength with a relatively sound dry density which could guarantee a good durability in resulting bricks made from these soil materials.Further test on the strength and durability of the compressed earth bricks (CEBs) made from these lateritic soils revealed a brick with compressive strength ranging between 6.33 and 15.57 MPa which are considered to be good strength coupled with its sound durability strength established over a period more than one year under a complete cycle of weather and seasonal conditions.In conclusion, lateritic soils from the study area were found to be suitable as materials for bricks (CEB) with good compressive and durability strength which qualifies them sustainable and cost effective materials for lowcost housing development.

Background. Rare earth element (REE) composition of atmospheric dust has recently been used to trace potential sources of dust pollution. Objective. The present study aimed to determine the sources of atmospheric pollution in the study area using REE patterns and determine their level of pollution. Methods. Twenty-five (25) atmospheric dust samples were collected in the study area, with five samples each from an industrial area, traffic area, dumpsite area, residential area and remote area in Ibadan, southwestern Nigeria. In addition, five (5) topsoil and two (2) rock samples (granite gneiss) were collected for comparison. Concentrations of REE were determined by inductively coupled plasma mass spectrometry (ICP-MS). Results. The ratio of lanthanum/cerium (La/Ce), especially in some locations in industrial area (1.5), traffic area (1.5) and to some extent dumpsite area (1.1) was higher than in soil (0.2), upper continental crust (0.5) and the minimum value of fluid catalytic crackers (1.0). Generally, the respective average values of the ratios of La/praseodymium (Pr), La/neodymium (Nd) and La/samarium (Sm) in industrial area (32.1, 7.8 and 52.6) and traffic area (14.9, 4.4 and 26.8) were higher than their respective averages in soil (4.4, 1.1 and 6.2), rock (5.7, 1.9 and 14.1), upper continental crust (4.4, 1.1 and 6.6) and the minimum value in fluid catalytic crackers (5.8, 3.7 and 37.0). Meanwhile, their corresponding value in the dumpsite area, residential area and remote area were lower or similar to the geological background levels. Discussion. The contamination factors of REEs in the atmospheric dust of the industrial area and traffic area were classified as heavily contaminated, especially with light lanthanoid elements in REE. The degree of contamination of REEs in the atmospheric dust of industrial area (30.9) and traffic area (18.8) fell within the considerable contamination category. The high values of the light lanthanoid ratio and the contamination indices were attributed to their emission from the fired-power plant and vehicular exhaust. Conclusions. Most of the composition of the atmospheric dust was sourced from the local geology of the study area as observed in the residential area and remote area, while the contamination in the industrial area and traffic area was attributed to human activities. Competing Interests. The authors declare no competing financial interests.