This paper discussed the urban heat island (UHI) intensity and local air quality by using observational data of project of the System of Air Quality Forecasting and Research (SAFAR) over Delhi during the month of May and December 2013. It is found that UHI magnitudes ~2.2˚C and ~1.5˚C are formed at the evening traffic hours during May and December respectively. Also, intensity of UHI < 0˚C over daytime is referred as Urban Cool Island (UCI) during May and December. The diurnal PM 2.5 concentration shows a bimodal pattern with peaks at morning and evening traffic hours during May and December. The planetary boundary layer height (PBLH) values show higher in magnitude during the daytime and lower in magnitude during the night-time. Whereas, the Ground Heat Flux values are lower during the daytime and higher during the night-time. The wind speed shows lower values during the UHI and higher magnitudes during the UCI formation hours. Concentration of PM 2.5 and wind speed shows a strong negative correlation during May (r = −0.56, p = 0.002) and December (r = −0.57, p = 0.001) at C V Raman (CVR) site, however, high values in the concentration of PM 2.5 during the low wind speed favour the condition for the formation of UCI. The regression analysis indicated that PM 2.5 plays a significant role in the daytime cooling and nighttime warming over the urban areas during the low wind speed condition.

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With rising anthropogenic activities, surface ozone levels have increased across different parts of the world including India. Studies have shown that surface ozone shows distinct characteristics across India, however these studies are mostly based on isolated locations. Any comprehensive and spatiotemporally consistent study on surface ozone is lacking thus far. Keeping these facts in mind, we utilize ground-based observations and reanalysis datasets to investigate the surface ozone variability, seasonality, and linkages with meteorology over India. A validation exercise shows that the Copernicus Atmosphere Monitoring Service Reanalysis (CAMSRA) reasonably compares against the ground-based observations. Results show that the CAMSRA ozone is in good agreement with the observations across India, where it shows better correlations (r>0.7) over southern regions and relatively lesser (> 0.5) over northern and eastern regions indicating larger variability and spread over these regions. We further quantify this agreement in terms of range, mean absolute error (MAE), and root mean square error (RMSE). Time series analysis shows that the CAMSRA captures seasonal variations irrespective of location. Spatial distribution of surface ozone shows higher (lower) concentrations of about 40-60 ppb (15-20 ppb) during pre-monsoon (monsoon) months over a broad region covering northern and western parts, and peninsular India. A prominent increase during May is noted over the northern region especially over Indo-Gangetic Plains (IGP). These seasonal variations are linked to solar radiation (SR), temperature, low-level circulation, and boundary layer height (BLH). Furthermore, Principal Component Analysis (PCA) is performed to understand the dominant patterns of spatiotemporal variability for different seasons. It is seen that the first (second) mode shows a high percentage variance explained ranging between 30-50% (10-20%). The time series of PCA-1 mode indicates an overall increasing trend across India with a notable increase over south and central India. The second mode indicates prominent variability over the IGP (southern India) in the pre-monsoon (post-monsoon) season, which shows significant interannual variability. During the monsoon season, an interesting dipole pattern is seen which closely resembles the active and break spell patterns of the Indian summer monsoon. Overall, the spatiotemporal variations in surface ozone are closely tied to meteorology while the rising trends indicate the potential role of increasing precursors across India.

Background: The era of flexible antennas started long ago because they are cost-effective while offering several advantages, such as good flexibility, stretchability, and compactness. Although several synthetic and natural polymers with good flexibility are available, the first flexible antenna is designed with polyimide materials (polymers), often known as engineering plastics. Objective: To fabricate a compact antenna with a higher gain than other existing ones and the bending loss of the proposed antenna is lower than other existing ones, this study proposes an ideal antenna. Methods: A polyimide (PI)-based flexible antenna with a defected ground structure is proposed for telemedicine and wireless applications, and we implement this antenna using microstrip feeding. The proposed antenna consists of a polyimide substrate with a thickness of 0.1 mm, a relative permittivity of 3.15, a loss factor of 0.0013, and a compact overall size of 25 x 32 x 0.1 mm3. Results: The proposed antenna operates on three frequencies, including 2.4 GHz (ISM or telemedicine application), 5.5 GHz (WiMAX band), and 7.5 GHz (wireless radio band). The proposed antenna produces impedance bandwidths of 10.16%, 14.54%, and 5.33% at frequencies of 2.4 GHz, 5.5 GHz, and 7.5 GHz, with gains of 4.9 dB, 5.1 dB, and 5 dB. Conclusion: The proposed antenna is simulated using Ansys High-Frequency Structure Simulator (HFSS) software. A good agreement is found between the measured and simulated results.

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