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A longitudinal stove intervention study was conducted in Northwest Bangladesh between August 2005 and June 2009 to quantify the reduction of indoor air pollution from a Bangladeshi manufactured and commercialized cookstove (the BCSIR improved stove). In the post-intervention phase of the study, the indoor particulate matter (PM) size distribution and chemical composition, as well as carbon monoxide (CO) concentration, were characterized in 40 kitchens, 50% with the BCSIR improved stoves and 50% with traditional stoves. The TSI DustTrak, P-TRAK and Q-TRAK Plus, along with the UCB Particle Monitor and the Onset HOBO, were simultaneously deployed to continuously characterize Carbon Monoxide (CO) and Particulate Matter (PM). Detailed chemical composition was quantified from X-Ray Flouroscence and Carbon Analyzer. Median 24-hr concentrations for CO and PM 2.5 were 2.5 mg/m 3 and 1.8 mg/m 3 , respectively, for the unimproved mud stove kitchens and were 2.0 mg/m 3 and 0.73 mg/m 3 , respectively, for the BCSIR improved stove kitchens. These differences were equivalent to 23% and 59% reduction of CO and PM 2.5 concentrations, respectively. The cook's daily exposure was estimated from these measurements to assess health impacts. Ultrafine particle number concentrations were 15,000 ± 7,200 pt/cm 3 during non-cooking periods and 75,000 ± 31,000 pt/cm 3 during cooking periods. Of the chemical composition of the PM 2.5 emitted from cooking, 59-60% was organic matter and 29-30% was elemental carbon. The predominant chemical species were elemental carbon (EC), organic carbon (OC), chlorine, and potassium. These results demonstrate possible reduction of PM and CO from cooking with improved stoves in rural areas in Bangladesh where solid fuels are used for cooking.

Azadirachta indica A. Juss, Dalbergia sissoo Roxb., and Melia azedarach L. are little studied species in nutrient return capabilities from leaf litter decomposition to maintenance of the soil fertility despite their importance in agroforestry practices of Bangladesh. A leaf litter decomposition experiment was conducted using a litterbag technique to assess the nutrient return efficiency of these species. The decomposition rate of leaf litter was highest for M. azedarach and lowest for D. sissoo. Rainfall and temperature of study sites showed a significant (p<0.05) positive relationship with the rate of leaf litter decomposition. The highest decay constant was observed for M. azedarach (6.67).Nitrogen and Phosphorus concentration in leaf litter showed a decreased trend sharply at the end of the first month, whereas rapid decrease of Potassium concentration was reported within 10 days. Conversely, higher concentration of nutrient was observed at the later stages of decomposition. All three species showed a similar pattern of nutrient release (K > N > P) during the decomposition process of leaf litter. Among the studied species, D. sissoo was best in terms of N and P return and A. indica was best in terms of K return.

The use of organic wastes in agriculture plays a great role in recycling essential plant nutrients, sustaining soil security as well as protecting the environment from unwanted hazards. This review article deals with the effect of different kinds of organic wastes on soil properties and plant growth and yield. Municipal solid waste is mainly used as a source of nitrogen and organic matter, improving soil properties and microbial activity that are closely related to soil fertility. Biowaste and food waste increase pH, nitrogen content, cation exchange capacity, water holding capacity, and microbial biomass in soil. Sewage sludge contains various amounts of organic matter and huge amounts of plant nutrients. Manure is a common waste which improves soil properties by adding nutrients and increases microbial and enzyme activity in soil. It also reduces toxicity of some heavy metals. These organic wastes have a great positive impact on soil physical, chemical, and biological properties as well as stimulate plant growth and thus increase the yield of crops.

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