Assimilative capacity of the atmosphere at Gorakhpur with respect to air pollution

The present study aims at seasonal and diurnal pollution potential at Gorakhpur in east Uttar Pradesh. To assess the pollution potential, meteorological data for five year period (1982-86) of Gorakhpur have been analyzed for four seasons viz; winter (December-February), summer (March-May), monsoon (June-September) and post monsoon (October-November). Season wise wind roses, stability, stability wind roses have been prepared and season wise diurnal variation of mixing height and ventilation coefficient have also been worked out. It is found that Gorakhpur has a better diffusion capacity in summer and poor in post monsoon followed by winter. Afternoon hours are better for vertical mixing. The winds are predominantly from southwest to west in all seasons except in monsoon when it blows from northeast to east. Based on this study, an appropriate location for industrialization has been suggested.

Studies of aerosols at Delhi

Aerosol size distrib ut ion and conce ntra tion have been measured us ing Ander sen par ticlecascade i-npactor and G.M .W. high vOI.ume sampler respectively. Sampling was done as per the sta bility conditionsof fum igation period. un stable convecuvc con dition s (free rmxmgj a nd the nocturna l sta ble per iod. In the pap er,concentr at ion , size distribu tio n and other relat ed studi es of pa rt iculate mat ter has been reported in the light ofsodar determ ined stability and mixing height of the A8L at Delhi.

Dispersion climatology for Patna and Gaya

The present study aims at seasonal and diurnal pollution potential around Patna, the capital region of Bihar and Gaya. To assess the pollution potential, meteorological data of two stations, VIZ., Patna and the neighbouring station Gaya for five year period (1984-88) have been analysed; The analysis has been done for four representative seasonal months, viz., winter (January), pre-monsoon (April), monsoon (August) and post-monsoon (October). The analysis shows no stable conditions in the day time and no unstable condition in the night time in each month. April shows higher frequency and January the lowest frequencies of unstable conditions. April has the highest mixing height and ventilation coefficient. From the results it has been concluded that day time is suitable for good dispersion in all the months. In the ca5e of existing industries, emission must be lessened during night time and particularly in the winter months. These results also suggest that pollutants are well dispersed in April and August. January and August may be regarded as the worst months for vertical diffusion of contaminants. As the predominant surface winds are easterly, any new Industrial set up should be in the west of the city in order to minimise the effects of pollutants.

Heat island study over Madras city and neighbourhood

Based on surface temperature, humidity and wind data collected from 77 points over a period of eight days in and around Madras using mobile surveys, the heat island characteristics at Madras have been assessed. The maximum heat island intensity is seen to be about 4°C. The humidity pattern apart from showing maritime influence also indicates a minimum over the heat pocket. The mixing height is found to be more over urban area than over rural area indicating lower pollution potential over the former due to the mixing over a larger depth than in the latter.

Air pollution climatology of Cochin for pollution management and abatement planning

The prevailing atmospheric condition is very important in determining the dispersion and dilution and thereby the resulting concentration of air pollutants, While high wind speed and stability conditions in general favour good inhaling of air pollutants conditions like inversion and calm winds cause for the build up of pollutants. In order to understand the different favourable and unfavourable conditions, some of the atmospheric aspects of air pollution are studied for the industrial city Cochin, situated on the west coast of India. Being a coastal city the frequency of occurrence of inversions and isothermal is not very high. Low values of mixing heights are observed in the southwest parts of the city during early morning hours, The study of spatial variation of mixing heights has revealed for the first time, that a single value of mixing height at the normal point of observation cannot be taken as a representative value for the whole city.

Using dispersion modeling for ground level concentration

A short range model calculating ground-level concentration from elevated sources is estimated, which realized a Fickian-type formula. Taking the source and mixing height are functions of the wind velocity and eddy diffusivity profiles. The model estimated with an exact solution of the advection diffusion equation is compared with experimental ground level concentrations using meteorological data collected near the ground.

Improved mixing height estimates from atmospheric LiDAR measurements

In this study, an improvement in the estimation of the mixing height is carried out by introducing a time-dependent maximum and minimum analysis altitude (TDMMAA) in the Haar wavelet covariance transform (WCT) technique applied to atmospheric light detection and ranging (LiDAR) measurements generally used in mixing height estimations. Results showed that the standard method usually overestimates the mixing height and that the proposed algorithm is more robust against clouds and residual layers in the boundary layer that generally occur in the nighttime and early morning. The TDMMAA method does have a bit of subjectivity especially in defining the analysis periods as well as the top and bottom of the analysis altitudes as it needs user experience and guidance. Moreover, the algorithm needs to be further objectively refined for automation and operational use, validated with in-situ profile measurements, and tested during different atmospheric conditions.

Assimilative capacity of the atmosphere at Lucknow with respect to air pollution

The present study aim at seasonal and diurnal pollution potential at Lucknow, the capital of Uttar Pradesh. To assess the pollution potential, meteorological data for five year period (1982-86) of Lucknow have been analyzed for four season, viz.; Winter (December-February), Summer (March-May), Southwest Monsoon (June-September) and Post Monsoon (October-November). Seasonwise wind roses, stability, stability wind roses have been prepared and season wise diurnal variation of mixing height and ventilation coefficient have also been worked out. It is found that Lucknow has a better diffusion capacity in summer and poor in winter. Afternoon hours are better for vertical mixing. The winds are predominant from west to north direction in all season except in monsoon where it blows from east direction.

Determination of airports’ atmospheric mixing height boundaries using operational data

Purpose This study aims to determine the distance and duration to reach airports mixing height of 3,000 feet limit. Airport operations significantly contribute to the aircraft landing and take-off (LTO) cycle. Eurocontrol’s SO6 data sets comprise several abutted segment data to analyse the duration and distance for specific flights. Design/methodology/approach Two consequential methods have been used to calculate the distance and destination from the SO6 databases. First, SQL filtering and pivot tables were formed for the required data. Second, over 583,000 data lines for a year of Boeing 747–400 aircraft routes were calculated and filtered for the monthly assessments. Findings LTO cycles’ durations have deviated −24% to 76% from the ICAO assumptions. Distance facts determined for specific airports as 2.57 to 3.66 nm for take-off and 5.02 to 23.25 nm for the landing. The average duration of the aircraft’s in mentioned airport take-off are 66 to 74 s and 40 to 50 s; averages have been calculated as 70 to 44 s. Landing durations have been calculated for four different airports as 173 to 476 s. Practical implications This study provides a re-evaluation chance for the current assumptions and helps for better assessments. Each airport and aircraft combinations have their duration and distance figures. Originality/value This study has calculated the first LTO distances in the literature for the aerodrome. This method applies to all airports, airline fleets and aircraft if the segmented SO6 data are available.