Assessment and management of air quality for an opencast coal mining area

A study for the assessment and management of the air quality was carried out at Lakhanpur area of Ib Valley Coalfield in Orissa state in India. The 24-h average concentrations of total suspended particulate (TSP) matter, respirable particulate matter (PM10), sulphur dioxide (SO2) and oxides of nitrogen (NOx) were monitored during 1 year period. Samplings were done at a regular interval through out the year at 13 monitoring stations in the residential areas and four monitoring stations in the mining/industrial areas. The 24-hr average TSP and PM10 concentrations ranged from 338.8 to 799.8 microg m(-3) and 102.5-425.6 microg m(-3) for industrial area, and 72.3-497.1 microg m(-3) and 40.8-171.9 microg m(-3) for residential area, respectively. During the study period 24-hr and annual average TSP and PM10 concentrations exceeded the respective standards set in the national ambient air quality standard (NAAQS) protocol at most residential and industrial areas. However, 24-hr and annual average concentrations of SO2 and NOx were well within the prescribed limit of NAAQS both in the residential and industrial areas. The annual and 24-hr average concentrations varied from 23.3 to 36.8 microg m(-3) and 16.0-55.2 microg m(-3) for SO2 and 23.9-41.9 microg m(-3) and 19.0-58.1 microg m(-3) for NOx, respectively. The temporal variations of TSP and PM10 fitted polynomial trend with an average correlation coefficient (R2) of 0.77 (+/-0.17) for TSP and 0.85 (+/-0.10) for PM10. On average the PM10 in the ambient air of the mining area constituted 31.94 (+/-1.76)% of the TSP. The linear regression correlation coefficient (R2) between TSP with PM10 and NOx with SO2 was 0.86 (+/-0.12) and 0.57 (+/-0.20), respectively. Maximal concentrations of TSP and PM10 occurred within the mining site based on the kriging technique. A management strategy is formulated for effective control of air pollution at source and other mitigative measures recommended including implementation of green belts around the sensitive areas where the concentration of air pollutants exceeded the standard limit.     

Low intervention soil remediation approaches

Traditional bioremediation approaches have been used to treat petroleum source contamination in readily accessible soils and sludges. Contamination under existing structures is a greater challenge. Options to deal with this problem have usually been in the extreme (i.e., to dismantle the facility and excavate to an acceptable regulated residual, or to pump and treat for an inordinately long period of time). The excavated material must be further remediated and cleanfill must be added to close the excavation. If site assessments were too conservative or incomplete, new contamination adulterating fill soils may result in additional excavation at some later date. Innovative, cost-efficient technologies must be developed to remove preexisting wastes under structures and to reduce future remediation episodes. An innovative soil bioremediation treatment method was developed and evaluated in petroleum hydrocarbon contaminated (PHC) soils at compressor stations of a natural gas pipeline running through Louisiana. The in-situ protocol was developed for remediating significant acreage subjected to contamination by petroleum-based lubricants and other PHC products resulting from a chronic leakage of lubricating oil used to maintain the pipeline itself. Initial total petroleum hydrocarbon (TPH) measurements revealed values of up to 12,000 mg/kg soil dry weight. The aim of the remediation project was to reduce TPH concentration in the contaminated soils to a level of <200 mg/kg soil dry weight, a level negotiated to be acceptable to state and federal regulators. After monitoring the system for 122 days, all sites showed greater than 99-percent reduction in TPH concentration.     

Controlling urban air pollution caused by households: uncertainty, prices, and income

We examine the control of air pollution caused by households burning wood for heating and cooking in the developing world. Since the problem is one of controlling emissions from nonpoint sources, regulations are likely to be directed at household choices of wood consumption and combustion technologies. Moreover, these choices are subtractions from, or contributions to, the pure public good of air quality. Consequently, the efficient policy design is not independent of the distribution of household income. Since it is unrealistic to assume that environmental authorities can make lump sum income transfers part of control policies, efficient control of air pollution caused by wood consumption entails a higher tax on wood consumption and a higher subsidy for more efficient combustion technologies for higher income households. Among other difficulties, implementing a policy to promote the adoption of cleaner combustion technologies must overcome the seemingly paradoxical result that efficient control calls for higher technology subsidies for higher income households.     

Assessment of ambient ozone effects on vegetation using snap bean as a bioindicator species

Tropospheric ozone is an air pollutant that is toxic to plants, causing visible injury to foliage and a reduction in growth and yield. The use of plant bioindicators is one approach to assess the ozone impacts in diverse geographical areas. The objective of this study was to evaluate snap bean (Phaseolus vulgaris L.) as a potential bioindicator species. Three snap bean genotypes known to exhibit a range of ozone sensitivity were grown in pots under charcoal-filtered (CF) or nonfiltered (NF) treatments in open-top chambers, or under ambient air (AA) conditions. Treatment effects on biomass were not significant at 56 days after planting (DAP), but midseason foliar injury increased in the NF and AA treatments relative to CF controls. An increase in ozone from 25 to 30 nL L(-1) in CF controls to approximately 50 nL L(-1) in the NF and AA treatments was found to suppress final pod dry weight per plant by 40 to 60% in the most sensitive genotype S156. The same treatments suppressed final pod dry weight by 20 to 30% in a moderately sensitive genotype Oregon-91, and by 10% or less in a tolerant genotype R123. An S156 to R123 yield ratio of approximately one was observed under CF conditions. The S156 to R123 yield ratio declined to 0.6 to 0.7 in the NF treatment and declined further to 0.4 to 0.5 in the AA treatment, suggesting that ozone impact was underestimated in the open-top chambers. The results suggest that a snap bean bioindicator system has the potential to detect ambient ozone effects at present-day ozone concentrations.