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Building an effective clean air action plan for a city's air pollution problem requires an extensive network of monitoring stations to represent spatial and temporal patterns and an understanding of the sources contributing to the problem. In India, the National Clean Air Programme (NCAP) was launched in 2019 to develop clean air action plans for 131 non-attainment cities, which includes conducting source apportionment studies and establishing emission baselines. As of February 2023, only 39 cities have completed the apportionment studies. In this paper, we present the essential resources needed to strengthen the ambient air monitoring networks, for designing a representative airshed size, sampling size, and sampling frequency, to effectively track the progress made in the cities for better air quality. The NCAP cities were grouped into 104 airsheds (5.3% of the national area), collectively representing a total of 164 cities and a total population of 295 million (21% of the national total). Of these airsheds, 73 contain only one city; 18 contain two cities, and nine contain three cities. Four airsheds – Delhi, Mumbai, Indore, and Chandigarh contain 10, 8, 5, and 5 cities respectively. To measure and analyse particulate matter pollution, a total of 2118 sampling sites are recommended for the 104 airsheds. Cities could consider hybrid monitoring networks by complementing existing regulatory monitoring network with a high-density network of low-cost/sensor-grade monitors. An airshed level air quality management plan, an enhanced monitoring network, and consolidation of information on emission sources, are crucial for optimizing the clean air efforts under NCAP. [Display omitted] • Defined 104 airsheds to represent 131 non-attainment cities under NCAP. • Defined the minimum number of monitors required in the airsheds. • Conducted high-resolution meteorological modelling to determine minimum filter sampling frequency per airshed. • Examples of hybrid networks to reduce monitoring costs. [ABSTRACT FROM AUTHOR]

This paper presents the long – term observational studies on aerosol optical properties measured at Sri Krishnadevaraya University (SKU) campus (14° 62′ N, 77° 65′ E, 331m asl), Anantapur, in southern India during 2007–2013 using a ground based Multi – Wavelength solar Radiometer (MWR). Seasonal mean values of Aerosol Optical Depth (AOD) for the whole study period were observed to be 0.34 ± 0.03, 0.45 ± 0.04, 0.24 ± 0.04, and 0.31 ± 0.03 during the winter, summer, monsoon and post – monsoon, respectively. Annual mean values of Ångström exponent (α) (turbidity coefficient (β)) varied from 0.68 ± 0.25 (0.18 ± 0.03) to 1.1 ± 0.12 (0.32 ± 0.12) during 2007–2013. However, high values of α in the range of 0.8–1.1 were observed during the winter, while low values in the range 0.3–0.7 were noticed during the monsoon. The frequency distribution of AODs during winter in the range of 0.2–0.4 is about 78%, while summer these were shifted from 0.3 to 0.6 around ∼70%, which indicated the dust strongly affects this region. The accumulated frequencies of Ångström exponent (α) less than 1.0 and greater than 1.0 were about 69% and 31%, respectively, occurred in the summer months indicates the dominance of coarse particles. Columnar size distributions, retrieved from the spectral optical depths, in general, show a bimodal log normal distribution in the optically active size range. The seasonal mean effective radius (R eff ) was found to be high in monsoon (∼0.61 μm) and low in winter (∼0.38 μm). The highest mean mass loading values are lies between 475 ± 36 to 769 ± 49 mg m −2 during the summer, whereas the lowest value in the range 204 ± 19 to 278 ± 23 mg m −2 during the monsoon. The difference between α and curvature effect have been studied as a function of AOD on seasonal basis. Finally, to understand the contribution of long range transported aerosols, we have investigated this analysis making use of back trajectories obtained from the HYSPLIT model for different seasons. [ABSTRACT FROM AUTHOR]

Abstract: Every year during the winter and pre-monsoon periods most of the Indian peninsula, Bay of Bengal and the adjoining Indian Ocean are affected by a polluted regional haze, known as the South Asian Winter Haze (SAWH). This article is the first of a series of three papers collectively anticipated at the central idea of retrieving aerosol component type and effective radius of the SAWH by incorporating experimental data of ground-based solar radiometer into Mie theory, and validation by collocated in-situ measurements. The work presented in this paper provides an approach to retrieve optical depths and their spectral curvature for SAWH at a tropical coastal station, Visakhapatnam (17.7°N, 83.3°E). A dataset comprised of 92 wintertime atmospheric optical depths are obtained from spectral extinction measurements of direct solar flux by means of a Multi-Wavelength Solar Radiometer during the period of October 2002 to February 2004. The inter-channel correlations established a linear relation and the airmass conditions specific to this dataset suggested a two-component linear model; the stable and variable components of which are analysed to obtain the mentioned optical parameters. Results indicate that the spectral curvature is best represented by a Lorentz model with a central wavelength of 0.40425±0.02945μm, a width of 0.40382±0.10253μm, a constant of 0.92623±0.33793, and a wavelength independent component of 0.95778±0.15678. Resonance-like structure of the obtained spectral curvature resembles wavelength dependent extinction characteristic of absorbing soot particles; thereby supports the key findings from INDOEX campaign. [Copyright &y& Elsevier]

Abstract: In this paper, we present the experimentally determined emission factors and emission estimates of particulate matter (PM), SO2, NO and NO2 emitted from biomass fuels used as energy in rural area of Indo-Gangetic Plain (IGP), India. Biomass fuel samples were collected at district level from this region. The burning of the collected biomass fuels is performed by using the modified dilution sampler based on studies done by . In this study, the emission factor represents the total period of burning including pyrolysis, flaming and smoldering. The average emission factor of PM from dung cake, fuel-wood and crop residue over Delhi, Uttar Pradesh, Punjab, Haryana, Uttarakhand and Bihar are estimated as 16.26 ± 2.29 g kg−1, 4.34 ± 1.06 g kg−1 and 7.54 ± 4.17 g kg−1 respectively. Similarly, the average emission factor of SO2, NO and NO2 from dung cake, fuel-wood and crop residue over this region are also determined (SO2: 0.28 ± 0.09 g kg−1, 0.26 ± 0.10 g kg−1 and 0.27 ± 0.11 g kg−1, NO: 0.27 ± 0.21 g kg−1, 0.41 ± 0.25 g kg−1 and 0.54 ± 0.50 g kg−1 and NO2: 0.31 ± 0.23 g kg−1, 0.35 ± 0.28 g kg−1 and 0.54 ± 0.47 g kg−1 respectively). The emission of PM, SO2, NO and NO2 from biomass fuels used as energy in rural household over, IGP are also estimated in this paper. The result shows the regional emission inventory from Indian scenario with spatial variability. [Copyright &y& Elsevier]

Abstract: This paper uses the 2006 IPCC Guidelines and latest country specific emission factors to estimate Indian methane emissions at sectoral and district level for the years 1990, 1995, 2005 and 2008. The estimates show that while methane emissions have increased steadily over past two decades, their share in India’s aggregate GHG emissions has declined from 31% in 1985 to 27% in 2008 mainly due to relatively higher growth CO2 emissions from the fossil fuels. The estimates for the year 2008 show that: i) agriculture sector, which employed two-thirds of India’s population and contributed 17% of GDP, accounted for 23% of India’s GHG emissions ii) 83% of country’s methane emissions are contributed by enteric fermentation, manure use and rice production, and iii) methane emissions from urban solid waste are steadily rising over the past two decades; their share in aggregate methane emissions has reached 8%. Resting on the disaggregated emissions estimates, the paper argues for using geographical and sectoral flexibilities to develop a roadmap for mitigation of methane emissions for India. [Copyright &y& Elsevier]

Abstract: Carbon footprint has become a term often used by the media in recent days. The human carbon footprint is professed to be a very serious global threat and every nation is looking at the possible options to reduce it since its consequences are alarming. A carbon footprint is a measure of the impact of human activities on earth and in particular on the environment; more specifically it relates to climate change and to the total amount of greenhouse gases produced, measured in units of carbon dioxide emitted. Effort of individuals in minimizing the carbon footprint is vital to save our planet. This article reports a study of the carbon footprint of various types of shopping bags (plastic, paper, non-woven and woven) using life cycle impact assessment (LCIA) technique in two stages. The first stage (baseline study), comprised the study of the impact of different types of shopping bags in the manufacturing phase, without considering their usage and disposal phases (cradle to gate stage). The LCIA was accomplished by the IPCC 2007 method, developed by the Inter Panel on Climate Change in SIMAPRO 7.2. The GWP (Global Warming Potential) values calculated by the IPCC 2007 method for 100 years were considered as a directive to compare the carbon footprint made by the different types of shopping bags under consideration. The next stage was the study of the carbon footprint of these bags including their usage and disposal phases (cradle to grave stage) and the results derived were compared with the results derived from the baseline study, which is the major focus of this research work. The values for usage and end-of-life phases were obtained from the survey questionnaire performed amongst different user groups of shopping bags in China, Hong Kong and India. The results show that the impact of different types of shopping bags in terms of their carbon footprint potential is very high if no usage and disposal options were provided. When the carbon footprint values from different disposal options were compared, the carbon footprint values were lower in the case where a higher percentage of reuse is preferred to recycling and disposing to landfill. The results indicate that a higher percentage of reuse could significantly scale down the carbon footprint. Once the shopping bags reached the point where they can no longer be reused, they must be forwarded to recycling options, rather than being disposed to landfill. At this juncture, consumer’s perceptions and behaviours in connection with the respective government’s policies in promoting & facilitating recycling systems could be critical in reducing the carbon footprint of various shopping bags. [Copyright &y& Elsevier]

This paper presents a new inventory of NMVOC emissions from anthropogenic sources in India for the year 2010. The main new element of this inventory, compared to previous work for India, is the use of new and more detailed data on solvent use sectors and oil production and distribution system. The results are presented at the national and state level for major sectors and VOC species. Finally, the annual emissions were spatially distributed at a fine resolution of 36 × 36 km 2 using detailed spatial information. The total anthropogenic NMVOC emissions in India in 2010 were estimated at 9.81 Tg which is in the range of the estimates made in most other studies. The majority of emissions (60%) originated from residential combustion of biomass for cooking. Solvent use sectors and oil production and distribution contributed about 20% followed by transport (12%) and open burning of agricultural residues (7%). Specie-wise distribution shows highest contribution from alkenes and alkynes (38%), followed by alkanes (22%), and aromatics (16%). [ABSTRACT FROM AUTHOR]

India has more than 100,000 brick kilns producing around 250 billion bricks annually. Indian brick industry is often a small scale industry and third largest consumer of coal in the country. With the growing demand for building materials and characterised by lack of pollution control measures the brick industry has a potential to cause adverse effects on the environment. This paper presents assessment of five brick making technologies based on the measurements carried out at seventeen individual brick kilns. Emissions of PM, SO 2 , CO and CO 2 were measured and these emissions were used to estimate the emission factors for comparing the emissions across different fuel or operating conditions. Estimated emission from brick kilns in South Asia are about 0.94 million tonnes of PM; 3.9 million tonnes of CO and 127 million tonnes of CO 2 per year. Among various technologies that are widely used in India, Zig zag and vertical shaft brick kilns showed better performance in terms of emissions over the traditional fixed chimney Bull's trench kilns. This suggests that the replacement of traditional technologies with Zig zag, vertical shaft brick kilns or other cleaner kiln technologies will contribute towards improvements in the environmental performance of brick kiln industry in the country. Zig zag kilns appear to be the logical replacement because of low capital investment, easy integration with the existing production process, and the possibility of retrofitting fixed chimney Bull's trench kilns into Zig zag firing. [ABSTRACT FROM AUTHOR]

The global burden of disease study estimated 695,000 premature deaths in 2010 due to continued exposure to outdoor particulate matter and ozone pollution for India. By 2030, the expected growth in many of the sectors (industries, residential, transportation, power generation, and construction) will result in an increase in pollution related health impacts for most cities. The available information on urban air pollution, their sources, and the potential of various interventions to control pollution, should help us propose a cleaner path to 2030. In this paper, we present an overview of the emission sources and control options for better air quality in Indian cities, with a particular focus on interventions like urban public transportation facilities; travel demand management; emission regulations for power plants; clean technology for brick kilns; management of road dust; and waste management to control open waste burning. Also included is a broader discussion on key institutional measures, like public awareness and scientific studies, necessary for building an effective air quality management plan in Indian cities. [ABSTRACT FROM AUTHOR]

Abstract: In the present paper, we have determined emission factor of chemical composition of the emission from the burning of biomass (e.g. Dung cake, Acacia, Neem, Mulberry, Indian Rosewood, Pigeon pea etc.) commonly used as a residential fuel in the rural sector of Indo-Gangetic Plain (IGP) (Delhi, Punjab, Haryana, Uttar Pradesh, Bihar and West Bengal), India. For comparison, we have selected only those biomass fuels, which are used in at least three of the above mentioned states. Dung cake from all the states reports highest emission of particulate matter (PM) (15.68 g kg−1), Organic Carbon (OC) (4.32 g kg−1) and Elemental Carbon (EC) (0.51 g kg−1). Among all biomass fuels studied, agricultural residue reports substantial amount of emission of Na+ (104 mg kg−1), K+ (331 mg kg−1) and Cl− (447 mg kg−1) particularly in Pigeon pea and Mustard stem. Eucalyptus (fuel wood) emits large amounts of Ca2+ (21.47 mg kg−1) and NO3 − (614 mg kg−1). The emission of PM from dung cake is higher in Delhi (19.31 g kg−1) and followed by Uttar Pradesh (17.58 g kg−1) > Haryana (15.46 g kg−1) > Bihar (14.99 g kg−1) > Punjab (12.06 g kg−1) > West Bengal (5.90 g kg−1). Carbonaceous aerosols (OC and EC) and dominant Ionic species (Cl−, K+, SO4 2−, NO3 − and PO4 3−) are altogether contributing 40–70% of total emissions. Characteristics and ratios of chemical species of emissions may help to develop a methodology of discriminating the sources of ambient particulate matter. Using a laboratory determined emission factor of chemical species, we have determined the emission budget over IGP, India. [Copyright &y& Elsevier]

Abstract: In this paper we have studied variability and growth rate of surface observed atmospheric Carbon Dioxide (CO2) concentrations over Cape Rama, west coast of India and its association with rainfall and vegetation over this region. Cape Rama is a maritime site which experiences a seasonal reversal wind pattern receiving air masses having marine (continental) signatures during summer (winter) monsoon season. This study reveals that summer monsoon (JJAS) precipitation and monthly values of atmospheric CO2 concentration during the season are well correlated. Negative correlations are seen with CO2 concentrations of concurrent months of the season as well as subsequent months. However the magnitudes of correlation coefficients are decreased till hot pre-monsoon season (MAM). Annual cycle and interannual variability show negative relationship between CO2 concentration and vegetation over the region. CO2 concentration shows increasing trend and NDVI shows decreasing trend. However, the magnitude of increasing trend of CO2 concentration is higher. Amplitude of decreasing phase of vegetation is higher than the amplitude of increasing phase. Though the results show certain link between CO2 and climate variability, further examination with dense and longer data may be needed to confirm the result. [Copyright &y& Elsevier]

Abstract: In Delhi, between 2008 and 2011, at seven monitoring stations, the daily average of particulates with diameter <2.5 μm (PM2.5) was 123 ± 87 μg m− 3 and particulates with diameter <10 μm (PM10) was 208 ± 137 μg m− 3. The bulk of the pollution is due to motorization, power generation, and construction activities. In this paper, we present a multi-pollutant emissions inventory for the National Capital Territory of Delhi, covering the main district and its satellite cities – Gurgaon, Noida, Faridabad, and Ghaziabad. For the base year 2010, we estimate emissions (to the nearest 000''s) of 63,000 tons of PM2.5, 114,000 tons of PM10, 37,000 tons of sulfur dioxide, 376,000 tons of nitrogen oxides, 1.42 million tons of carbon monoxide, and 261,000 tons of volatile organic compounds. The inventory is further spatially disaggregated into 80 × 80 grids at 0.01° resolution for each of the contributing sectors, which include vehicle exhaust, road dust re-suspension, domestic cooking and heating, power plants, industries (including brick kilns), diesel generator sets and waste burning. The GIS based spatial inventory coupled with temporal resolution of 1 h, was utilized for chemical transport modeling using the ATMoS dispersion model. The modeled annual average PM2.5 concentrations were 122 ± 10 μg m− 3 for South Delhi; 90 ± 20 μg m− 3 for Gurgaon and Dwarka; 93 ± 26 μg m− 3 for North-West Delhi; 93 ± 23 μg m− 3 for North-East Delhi; 42 ± 10 μg m− 3 for Greater Noida; 77 ± 11 μg m− 3 for Faridabad industrial area. The results have been compared to measured ambient PM pollution to validate the emissions inventory. [Copyright &y& Elsevier]

Abstract: A prerequisite to an air quality management plan for a city is some idea of the main sources of pollution and their contributions for a city. This paper presents the results of an application of the SIM-air modeling tool in six Indian cities – Pune, Chennai, Indore, Ahmedabad, Surat, and Rajkot. Using existing and publicly available data, we put together a baseline of multi-pollutant emissions for each of the cities and then calculate concentrations, health impacts, and model alternative scenarios for 2020. The measured annual PM10 (particulate matter with aerodynamic diameter less than 10 micron meter) concentrations in μg m−3 averaged 94.7 ± 45.4 in Pune, 73.1 ± 33.7 in Chennai, 118.8 ± 44.3 in Indore, 94.0 ± 20.4 in Ahmedabad, 89.4 ± 12.1 in Surat, and 105.0 ± 25.6 in Rajkot, all exceeding the annual standard of 60 μg m−3. The PM10 inventory in tons/year for the year 2010 of 38,400 in Pune, 50,200 in Chennai, 18,600 in Indore, 31,900 in Ahmedabad, 20,000 in Surat, and 14,000 in Rajkot, is further spatially segregated into 1 km grids and includes all known sources such as transport, road dust, residential, power plants, industries (including the brick kilns), waste burning, and diesel generator sets. We use the ATMoS chemical transport model to validate the emissions inventory and estimate an annual premature mortality due to particulate pollution of 15,200 for the year 2010 for the six cities. Of the estimated 21,400 premature deaths in the six cities in 2020, we estimate that implementation of the six interventions in the transport and brick kiln sectors, can potentially save 5870 lives (27%) annually and result in an annual reduction of 16.8 million tons of carbon dioxide emissions in the six cities. [Copyright &y& Elsevier]

Abstract: The significant role of aerosol–cloud interaction during the large-scale drought producing breaks of 2009 Indian Summer Monsoon is investigated in the present paper. This mega drought had already been attributed to two long breaks, one in June and the other in July-August. While Central India (CI) and northern parts of the country experienced deficient rainfall, the rainfall over the southern Peninsular India (PI) remained close to normal. During the first break in June, which was associated with mid-latitude intrusion of dry air, the Twomey effect (positive aerosol indirect effect – AIE) was a dominant factor inhibiting efficient precipitation over CI region, as compared to that over PI. Moreover, the number of days that experienced significant (at 5% level of significance) positive AIE during the first break was more over CI compared to the same during the second break. The AIE on ice clouds was not as significant as that of the low-clouds. The resulting cloud properties during both break and active phases over CI differ significantly from that over PI for the corresponding periods. The positive AIE mentioned here is attributed to the large-scale deficit of moisture supply to the CI region due to dynamical reasons. However, it is shown that under ample availability of moisture, more aerosols could invigorate deep clouds over specific regions even during the break spells. [Copyright &y& Elsevier]

Abstract: Aerosol Robotic Network (AERONET) aerosol optical depth (AOD) and almucantar retrievals (single scattering albedo (SSA) and aerosol size distribution) from 2005–2009 in Beijing and Kanpur are used to analyze differences and similarities in aerosol optical properties over these two regions. The examination of monthly mean AOD (440 nm) shows that maximum and minimum values occurred in summer and winter, respectively, for Beijing, while the range in AOD in Kanpur was lower. Precipitation in both Beijing and Kanpur peaked in summer; however, the columnar water vapor (CWV) exhibited a high correlation with AOD in Beijing (R 2 = 0.79) but had a weak relationship with AOD in Kanpur (R 2 = 0.13). The Angstrom exponent (α, 440–870 nm) generally increased linearly as the fine mode fraction (FMF) of AOD (500 nm) increased for FMF < 90% in both regions, with a high correlation of R 2 > 0.96. However a clear decrease in α for FMF > 90% found in Beijing is not shown distinctly in Kanpur, and is mainly due to the higher aerosol loading in this FMF bin at Beijing (AOD at 440 nm > 2.2) which results in a stronger coagulation of fine mode particles. Bimodal seasonally-averaged size distributions reveals similar aerosol mixtures composed of fine pollution particles and coarse dust particles in both regions. The analysis of spectral SSA as a function of α is emphasized in this paper. The average SSA at 440 nm in both regions shows a similar low dynamic range of ∼0.03 for α < 1.4. The obvious increase in SSA at 440 nm for α > 1.4 in both regions can be attributed to a higher FMF leading to fine mode coagulation. However, the distinctly smaller increase in Kanpur suggests that fine mode aerosols at Beijing are less absorbing than those at Kanpur. The visibly lower SSA at 675 nm at Kanpur compared to that at Beijing for α > 0.4 is due to a larger find-coarse mode separation radius of ∼0.76 μm in Beijing versus a value lower than ∼0.58 μm in Kanpur. Another reason lies in the weaker absorption by fine mode aerosols in Beijing. The distinctly lower near-infrared SSA in Kanpur when α < 1.4, compared to Beijing, may be attributed to lower aerosol concentrations in all α bins, resulting in less aggregation of absorbing black carbon particles on coarse particles in Kanpur. The classification of aerosol properties shows that the AOD accumulation mode in all seasons, even including spring, in Beijing and in post-monsoon and winter seasons in Kanpur can be attributed to fine particle coagulation or hygroscopic growth; during pre-monsoon and monsoon seasons in Kanpur, it is due to coarse mode particle accumulation or cloud contamination. [Copyright &y& Elsevier]

Abstract: Landfills are important anthropogenic sources of methane (CH4) emission especially in fast urbanizing countries. This paper presents the CH4 emission estimations carried out using the in-situ CH4 measurements, IPCC 1996 Default methodology (DM), Modified Triangular Method (MTM) and First Order Decay (FOD) method for the three landfills currently operational in the capital city Delhi of India. The in-situ methodology has yielded the landfills specific methane emission factors (EFs). The annual average methane emission rates from three landfills namely, Ghazipur (GL), Bhalswa (BL) and Okhla (OL) are 14.6, 23.6 & 7.5 Gg y−1 by DM; 13.3, 10.6 & 7.2 Gg y−1 by the FOD; 17.0, 13.7 and 10.7 Gg y−1 by the MTM; and 4.6, 4.2 and 1.4 Gg y−1 by the in-situ measurement method respectively. The CH4 EFs have been found to be 9.7 ± 2.6, 5.5 ± 1.6 and 5.5 ± 1.7 g kg−1 of waste respectively for the GL, BL and OL landfills in Delhi. The study reveals that in-situ methodology seems to provide better representative emission estimation compared to other methods. The FOD method also yields comparable results with that of in-situ methodology in cases where good waste composition data is available. [Copyright &y& Elsevier]

Abstract: In India the emissions rate and fuel consumption of intra-city buses are estimated using the European driving cycles, which don’t represent Indian driving conditions and in-use operation of vehicles. This leads to underestimation or overestimation of emissions and fuel consumption. In this context, this paper offers some insight into the driving characteristics of intra-city buses using a Global Positioning System. The study has revealed that irrespective of road type and time of travel, a higher percentage of time is spent in idle mode. This is primarily due to alighting and boarding of passengers at regular intervals and fixed delays caused by traffic lights. More than 90 percent of trips have an average speed of less than 30 km h−1. This study has also developed an intra-city bus driving cycle for Chennai and compared it with some well-known international driving cycles. It has revealed that Chennai has unique driving characteristics and, therefore, it may not be appropriate to adopt a driving cycle of another country or city. [Copyright &y& Elsevier]

Abstract: This paper presents the characteristics of particulate matter (PM) mass concentrations (PM10, PM2.5 and PM1) emitted from heterogeneous traffic in Chennai city during monsoon, winter and summer seasons of the year 2007–2009. The heterogeneous traffic characteristics at the study region indicated dominance of 2-wheelers (58%) followed by the 4-wheelers (29%), 3-wheelers (7%), light commercial vehicle (LCV = 2%) and heavy commercial vehicle (HCV = 4%). The vintage analysis of vehicles showed that 11, 24, 35 and 30% of the total vehicles were 15, 10, 5 and <5 years old vehicles, respectively (75% of LCV and 70% of HCV were older than 10 years and 82% of 2W, 85% of 3W, 79% of 4W were less than 10 years old). The travel demand on weekdays at the study site revealed that 60% of the traffic in the morning peak hours was due to school and office trips and 40% was due to the business trips. During the weekends the peak rush hours traffic was dominated by travel demand (90%) due to tourists and pleasure trips. At study region, the PM10 comprised a large fraction of PM2.5 (56% of PM2.5 and 44% of PM1), while PM2.5 comprised a large proportion of PM1 (81%). The estimated PM2.5/PM10 ratios for monsoon, winter and summer seasons were ranged between 0.44–0.62, 0.66–0.76 and 0.62–0.73, respectively. The high PM2.5/PM10 ratios (R 2 = 0.92–0.98) during peak hour indicated significant contribution from the vehicular emissions. Further, it was found that the PM10, PM2.5 and PM1 concentrations at the study site followed similar trend of 2W, 3W, 4W and HCV during morning peak hour traffic. The analysis of 24-hr average PM10, PM2.5 and PM1 concentrations showed maximum during monsoon (188.75 ± 71.75, 83.91 ± 33.18, 65.81 ± 28.47 μg/m3) and winter (134.58 ± 64.55, 72.95 ± 39.27, 59.00 ± 31.15 μg/m3) and minimum during summer (75.96 ± 43.15, 42.16 ± 19.76, 31.40 ± 16.05 μg/m3) seasons. The 24-hr average PM10 and PM2.5 indicated maximum violations of Indian national ambient air quality standards (NAAQS for PM10 = 100 μg/m3 and PM2.5 = 60 μg/m3) during winter and monsoon seasons and minimum during summer season. Further, PM10 and PM2.5 concentrations were well above the prescribed 24-hr average world health organization (WHO) standards (PM10 = 50 μg/m3; PM2.5 = 25 μg/m3). The PM chemical characterization indicated the dominance of soil based crustal elements (74%) – Al, Ca, Fe and Mg, salt based components (16%)-Na and K, and the other trace elements (10%) such as B, Ba, Cd, Co, Cr, Cu, Ga, Mn, Mo, Ni, Pb, Rb, Se, Sr, Te, V and Zn. The percentage composition of different group of elements indicates traffic as the main source of PM emission at the study site. The ion analysis showed presence of more anions (36–82%) than the cations (18–64%). SO4 2− and Mg2+ were major constituents. [Copyright &y& Elsevier]

Abstract: Aerosol measurements over a tropical semi-arid site in Anantapur (14.62°N, 77.65°E, 331 m asl), India, provide the variabilities of aerosol characteristics for the period of January 2007–December 2008. The mean values of aerosol optical depth at 500 nm (AOD500 nm) over 2-year period are found to be 0.37 ± 0.11, 0.39 ± 0.13 and 0.30 ± 0.10 during winter, summer and monsoon seasons, respectively. A rather systematic variation is seen with AOD peaking in the month of March, falling off gradually to the lowest value in June and increasing slowly superposed with some modulations, which show a weak secondary peak in October. The mean and standard values of the Ångström exponent, α (turbidity coefficient, β), are found to be 1.06 ± 0.33 (0.17 ± 0.05) during winter, 0.97 ± 0.35 (0.22 ± 0.04) during summer and 0.85 ± 0.26 (0.16 ± 0.06) during monsoon. The frequency distribution of α is relatively broad with two modes for dusty (α < 1) and non-dusty (α > 1) situations. This frequency distribution of α reveals a great dispersion of a values in all seasons thus denoting variability in the aerosol-size distribution. In this study, spectral AOD and Ångström exponent data are analyzed to obtain information about the adequacy of the simple use of the Ångström exponent and its variation for characterizing optical properties of aerosols, and exploring possibilities for a more efficient characterization of them. Using the least-squares fit method, the Ångström parameter, α, is calculated in the spectral interval 380–850 nm, along with coefficients a1 and a2 of the second-order polynomial fit to the plotted logarithm of AOD versus the logarithm of wavelength. The correlations between the coefficients a1 and a2 with months and α are discussed in the paper. [Copyright &y& Elsevier]

Abstract: This paper discusses the extent of Black Carbon (BC) radiative forcing in the total aerosol atmospheric radiative forcing over Pune, an urban site in India. Collocated measurements of aerosol optical properties, chemical composition and BC were carried out for a period of six months (during October 2004 to May 2005) over the site. Observed aerosol chemical composition in terms of water soluble, insoluble and BC components were used in Optical Properties of Aerosols and Clouds (OPAC) to derive aerosol optical properties of composite aerosols. The BC fraction alone was used in OPAC to derive optical properties of BC aerosols. The aerosol optical properties for composite and BC aerosols were separately used in SBDART model to derive direct aerosol radiative forcing due to composite and BC aerosols. The atmospheric radiative forcing for composite aerosols were found to be +35.5, +32.9 and +47.6Wm−2 during post-monsoon, winter and pre-monsoon seasons, respectively. The average BC mass fraction found to be 4.83, 6.33 and 4μgm−3 during the above seasons contributing around 2.2 to 5.8% to the total aerosol load. The atmospheric radiative forcing estimated due to BC aerosols was +18.8, +23.4 and +17.2Wm−2, respectively during the above seasons. The study suggests that even though BC contributes only 2.2–6% to the total aerosol load; it is contributing an average of around 55% to the total lower atmospheric aerosol forcing due to strong radiative absorption, and thus enhancing greenhouse warming. [Copyright &y& Elsevier]

Abstract: A decentralized emission inventories are prepared for road transport sector of India in order to design and implement suitable technologies and policies for appropriate mitigation measures. Globalization and liberalization policies of the government in 90''s have increased the number of road vehicles nearly 92.6% from 1980–1981 to 2003–2004. These vehicles mainly consume non-renewable fossil fuels, and are a major contributor of green house gases, particularly CO2 emission. This paper focuses on the statewise road transport emissions (CO2, CH4, CO, NOx, N2O, SO2, PM and HC), using region specific mass emission factors for each type of vehicles. The country level emissions (CO2, CH4, CO, NOx, N2O, SO2 and NMVOC) are calculated for railways, shipping and airway, based on fuel types. In India, transport sector emits an estimated 258.10 Tg of CO2, of which 94.5% was contributed by road transport (2003–2004). Among all the states and Union Territories, Maharashtra''s contribution is the largest, 28.85 Tg (11.8%) of CO2, followed by Tamil Nadu 26.41 Tg (10.8%), Gujarat 23.31 Tg (9.6%), Uttar Pradesh 17.42 Tg (7.1%), Rajasthan 15.17 Tg (6.22%) and, Karnataka 15.09 Tg (6.19%). These six states account for 51.8% of the CO2 emissions from road transport. [Copyright &y& Elsevier]

Abstract: In this second of two companion papers, we quantify for the first time the global impact on premature mortality of the inter-continental transport of fine aerosols (including sulfate, black carbon, organic carbon, and mineral dust) using the global modeling results of (Liu et al., 2009). Our objective is to estimate the number of premature mortalities in each of ten selected continental regions resulting from fine aerosols transported from foreign regions in approximately year 2000. Our simulated annual mean population-weighted (P-W) concentrations of total PM2.5 (aerosols with diameter less than 2.5 μm) are highest in East Asia (EA, 30 μg m−3) and lowest in Australia (3.6 μg m−3). Dust is the dominant component of PM2.5 transported between continents. We estimate global annual premature mortalities (for adults age 30 and up) due to inter-continental transport of PM2.5 to be nearly 380 thousand (K) in 2000. Approximately half of these deaths occur in the Indian subcontinent (IN), mostly due to aerosols transported from Africa and the Middle East (ME). Approximately 90K deaths globally are associated with exposure to foreign (i.e., originating outside a receptor region) non-dust PM2.5. More than half of the premature mortalities associated with foreign non-dust aerosols are due to aerosols originating from Europe (20K), ME (18K) and EA (15K); and nearly 60% of the 90K deaths occur in EA (21K), IN (19K) and Southeast Asia (16K). The lower and higher bounds of our estimated 95% confidence interval (considering uncertainties from the concentration–response relationship and simulated aerosol concentrations) are 18% and 240% of the estimated deaths, respectively, and could be larger if additional uncertainties were quantified. We find that in 2000 nearly 6.6K premature deaths in North America (NA) were associated with foreign PM2.5 exposure (5.5K from dust PM2.5). NA is least impacted by foreign PM2.5 compared to receptors on the Eurasian continent. However, the number of premature mortalities associated with foreign aerosols in NA (mostly occurring in the U.S.) is comparable to the reduction in premature mortalities expected to result from tightening the U.S. 8-h O3 standard from 0.08 ppmv to 0.075 ppmv. International efforts to reduce inter-continental transport of fine aerosol pollution would substantially benefit public health on the Eurasian continent and would also benefit public health in the United States. [Copyright &y& Elsevier]

As the world gets ready to begin the second decade of the twenty-first century, global climate change has been recognized as a real threat to civilization as we know it. The rapid and successful economic growth of developing nations, particularly China and India, is contributing to climate change. The route to initial economic success in China followed that of the developed nations through the development of industries. Unfortunately, China''s environmental protection efforts have not been the same as in developed countries because China is vastly different culturally, socially, economically and, especially, politically from developed nations. When China started to deal with environmental concerns in the late 1970s, it took advantage of the experiences of other countries in establishing environmental standards and regulations, but it did not have a model to follow when it came to implementing these standards and regulations because of the abovementioned differences. Economically, China is transitioning from an agricultural base into an industrial base; however, even now, 60% of the population remains farmers. China has been and still is heavily dependent upon coal for energy, resulting in serious atmospheric particulate pollution. While growing efforts have been expended on the environment, at this juncture of its economic development, China would be well served to revisit the traditional “develop first and clean up later” approach and to find a balance between development and protecting the environment. Against this backdrop, a reflective look of the effort to manage air quality from 1949–2008 (with an emphasis on the past 30years) in China is presented in this paper. The environmental component of the 2008 Olympic Games is examined as a special example to illustrate the current measures being used to improve air quality in China. [Copyright &y& Elsevier]

The main objective of this paper is to evaluate the noise pollution problem in the Varanasi city and its effect on the exposed people. The study revealed the fact that noise levels have reached an alarming level. The result of the study indicated the fact that 85% of the people were disturbed by traffic noise, about 90% of the people reported that traffic noise is the main cause of headache, high BP problem, dizziness and fatigue. People having higher education and income level are much aware of the health impact due to traffic noise. Marital status was found to be significantly affecting the annoyance level caused by traffic noise. Traffic noise was found to be interfering daily activities such as at resting, reading, communication etc. [Copyright &y& Elsevier]

Recent analysis of trends in global short-wave radiation measured with pyranometers in major cities in India support a decrease in solar radiation in many of those cities since 1990. Since direct and diffuse radiation measurements include cloud effects, spring and summer dust and the variable summer monsoon rains, we concentrate in this paper on wintertime (November–February) aerosol optical depth measurements. The aerosol optical depth is derived from cloud-free turbidity measurements beginning in the 1960s and more recent sun photometer direct aerosol optical depth measurements. We compare the sun photometer derived trends with the pyranometer-derived trends using a radiative transfer model. These results are then compared to total ozone mapping spectrometer (TOMS) satellite-derived regional aerosol optical depths from 1980 to 2000. The results show that inclusion of the earlier turbidity measurements helps to establish an increasing regional turbidity trend. However, most of the increasing trend is confined to the larger cities in the Ganges River Basin of India (mainly Calcutta and New Delhi) with other cities showing a much less increase. Regional satellite data show that there is an increasing trend in aerosol off the coast of India and over the Ganges River Basin. The increase over the Ganges River Basin is consistent with population trends over the region during 1980–2000. [Copyright &y& Elsevier]

This paper uses spectral methods to analyze changes in air quality at a single monitoring site in Delhi since 2000. Power spectral density calculations of daily concentration data for particulate matter (PM10), carbon monoxide (CO), oxides of nitrogen (NO x ) and oxides of sulfur (SO x ) reveal the presence of trends and periodic oscillations for all the pollutants. Singular Spectrum Analysis (SSA) is used to decompose daily data into statistically significant non-linear trends, seasonal cycles and other oscillations. Periods of sharp reductions were observed for both SO x and CO concentrations in 2001 and 2002, respectively. NO x concentration trends show a sustained rise from 2000 to 2004, followed by small decline thereafter. PM10 concentration trends remain essentially unchanged over the time period. All pollutants also show strong annual and biannual cycles. The observed trends in CO and NO x likely relate changes in Delhi''s vehicular traffic emissions. The sharp drop in both the trend and amplitude of the seasonal cycle of CO coincides with the switch to Compressed Natural Gas (CNG) as a fuel for Delhi''s public transport fleet. Observed changes in SO x and PM10 concentrations were most likely caused by sources unrelated to vehicular traffic. [Copyright &y& Elsevier]

This paper examines the role of meteorology in linking near surface emissions of particulate matter and associated ambient concentrations in urban areas. The examination is conducted with two models: a steady state model based on urban dispersion models developed earlier, and an unsteady state model that accounts for time varying meteorological and emission inputs. After conducting sensitivity studies with the models, they are applied in Pune, India to (a) check consistency between estimates of surface emissions of particulate matter (with aerodynamic diameters of less than m, referred to as PM and observed ambient concentrations and (b) identify the variables that govern air quality. Results from the modeling exercise indicate that (1) nighttime meteorology governs both hourly as well as 24h averaged concentrations and (2) because the wind speeds in urban areas are typically low, concentration estimates from the steady state model differ substantially from those of the unsteady state model during the nighttime hours both in magnitude and in timing of the peaks; however, the difference between the 24h averaged concentrations from the two models is less than 5% for the cases considered here. Because our understanding of nighttime meteorology in urban areas is limited, there is a need for experimental programs to relate the diurnal variation of concentrations with associated meteorology, especially during the night. [Copyright &y& Elsevier]

Abstract: This paper provides the trends of greenhouse gas (GHG) and local air pollutant emissions of India for 1985–2005. The GHGs covered are six Kyoto gases, namely carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), perfluorocarbons (PFCs), hydrofluorocarbons (HFCs) and sulfur hexafluoride (SF6). The local air pollutants are sulfur dioxide (SO2), nitrogen oxides (NO X ), carbon monoxide (CO) and total suspended particulates (TSP). These estimates incorporate some of the most recent scientific assessments for India. The multigas emissions have varied sectoral and fuel-based dominance, as well as regional distribution patterns. Coal consumption in power sector dominates CO2 and SO2 emissions, while power and road transport equally contribute to NO X emissions. Rice cultivation and livestock-related emissions from the agriculture sector dominate CH4 emissions, while synthetic fertilizer use in the same sector is the major source of N2O emissions. PFC emissions are dominated by C2F6 and CF4 emissions from aluminum production. The majority of HFC emissions are contributed by HFC-23, a by-product during the production of HCFC-22 that is widely used in refrigeration industry. CO emissions have dominance from biomass burning. Particulate emissions are dominated by biomass burning (residential sector), road transport and coal combustion in large plants. These varied emission patterns provide interesting policy links and disjoints, such as—which and where mitigation flexibility for the Kyoto gases, exploring co-benefits of CO2 and SO2 mitigation, and technology and development pathway dependence of emissions. The present inventory assessment is a pointer to the future emission pathways for India wherein local air pollutant and GHG emissions, although connected, may not move in synchronization and therefore would require alignment through well crafted development and environment strategies. [Copyright &y& Elsevier]

Abstract: Chemical simulations in most of the atmospheric chemistry models require surface emissions in a specific form (gridded), which are often not available. Simple interpolation of broader level emissions to obtain gridded data may lead to erroneous results. An attempt has been made in this paper to develop a geographical information system (GIS) based methodology for distributing the emissions from a broader level inventory to finely gridded emission values, considering local micro-level details and activity data. Given the importance of Carbon Monoxide emissions in ozone pollution chemistry over India, an emission inventory for CO from various sources for India has been used to demonstrate the GIS-based gridding methodology. The total CO emissions over India for 2001, which are estimated to be around 69.0Tgyear−1, have been downscaled source-wise (distinguishing between rural and urban bio-fuel, vehicular traffic, coal and biomass burning) from state-level (28 points) to district level (∼500 points) before mapping through a GIS utility and finally gridded to a 1°×1° resolution with a data loss of only about 13%. The final results provide detailed information with emission “hot spots” and the relative contribution of various sources. This article focuses on usage of the GIS based statistical methodology for gridding the inventory and the results obtained thereof are discussed. [Copyright &y& Elsevier]

Abstract: Climatic change is one of the most important issues of present times. Unlike the greenhouse gases, which have a predominantly warming effect, atmospheric aerosols could either warm or cool the atmosphere depending upon the size, distribution and optical properties. Of all the climatic elements, temperature plays a major role in detecting climatic change brought about by urbanization and industrialization. This paper, therefore, attempts to study temporal variation in temperature over Pune city, India, during the period 1901–2000. The long-term change in temperature has been evaluated by Mann–Kendall rank statistics and linear trend. The analysis reveals significant decrease in mean annual and mean maximum temperature. This decrease in temperature is more pronounced during the winter season, which can be ascribed to a significant increase in the amount of suspended particulate matter (SPM) in the ambient air during the last decade. On the contrary, monsoon season shows warming. This warming can be attributed to a significant increase in the low cloud amount. [Copyright &y& Elsevier]

India is a large producer and user of chlorofluorocarbons (CFCs) in the refrigeration and air-conditioning (RAC) sector. Government of India has taken several steps to restrict the production and consumption of CFCs. Refrigerant conservation through recovery, recycling (R&R) and reclamation is one way of reducing emissions and encouraging timely phase out of CFCs in developing countries. CFC recovery, recycling and reclamation have been mandated in many developed countries. However, this practice is yet to make an impact in India although it is practiced in MAC sector to some extent. India is planning for the final phase out of CFCs in the RAC service sector, in which R&R will be one of the components.A model has been developed to assess the economics of R&R for some typical parameters in developing counties like India. The model suggests that the enterprises recycling 1500 kg/a will break even within 1 year for all scenarios. However, R&R may not be cost effective for small workshops and low volume refrigerant vendors until either the price of CFC goes up or the cost of R&R unit is subsidized. A nationwide survey on RAC service sector revealed that in India, there are very few enterprises handling more than 500 kg/a. Therefore, there is a need to provide the RAC service sector with adequate and innovative financial incentives.This paper attempts to study the issues related to R&R for various sub-sectors of RAC in developing countries with an emphasis on cost effectiveness. India is used as a model for this study. [Copyright &y& Elsevier]

This paper presents the measurements of gaseous SO2, NO2, HNO3 and NH3 and particulate NH4+, NO3−and SO42− at Rampur, a rural site of semi-arid region of India and annual mean concentrations are 3.7±2.2, 7.3±3.7, 0.7±0.6 and 6.7±4.2 and 1.0±0.4, 1.1±1.3 and 2.6±1.6 μg m−3, respectively. Seasonal variation with higher concentration in winter is observed for gaseous SO2, NO2, and NH3 and particulate NH4+. The concentration of HNO3 and particulate NO3−and SO42− are higher in summer. Summer to winter ratio of HNO3 and particulate NO3− are 3.8 and 1.8, respectively, showing seasonal variation is more pronounced in case of HNO3 than particulate NO3−. The ratio of gaseous NH3 to particulate NH4+ (NH3/NH4+) is more than 1 probably due to basic nature of aerosol. Examination of equilibrium between gaseous NH3 and HNO3 and particulate NH4NO3 shows observed equilibrium constant is lower than theoretical equilibrium constant in summer and vice versa in winter. [Copyright &y& Elsevier]

Since the past two decades, high aerosol loading is being observed over the Indian mainland. It becomes necessary to continuously monitor and understand the distribution of aerosol loading over the Indian landmass, as it might have serious health and climatic implications. Whereas there have been extensive studies reporting seasonal distribution and trends of columnar aerosol amounts over the Indian region using data from ground based as well as space borne measurements, in-depth studies on the aerosol vertical profile distribution and in particular, seasonal trends are still lacking. This paper demonstrates the seasonal variability of aerosol vertical structure over the Indian mainland using decadal daily datasets (2009–2018) from CALIOP Lidar (onboard NASA-CNES's CALIPSO satellite) augmented by the variability in columnar AOD from MODIS (onboard NASA's AQUA and TERRA platforms). The changing aerosol amounts in both vertical and total column levels have also been presented. Over Indian landmass, we could find statistically significant increasing trends in aerosol extinction within lower altitude levels during all the seasons. The trends in the vertical distribution of aerosols are also compared with respect to trends in AOD derived from MODIS (Aqua/Terra). Additionally, we have also examined the seasonal variability and trends of aerosol extinction over five selected cities (based on pollution and population levels) of the country. • Decadal-scale seasonal variability of aerosol extinction profiles over India. • Increasing vertical and columnar trends of aerosols during all seasons. • Small and spherical particles more dominant during October–February. [ABSTRACT FROM AUTHOR]

Current ozone (O 3) concentration levels entail significant damages in crop yields around the world. The reaction of the emitted precursors (mostly methane and nitrogen oxides) with solar radiation contribute to O 3 levels that exceed established thresholds for crop damage. This paper shows current and projected (up to 2080) relative yield losses (RYLs) driven by O 3 exposure for different crops and the associated economic damages applying dynamic crop production and prices that are calculated per region and period. We adjust future crop yields in the Global Change Assessment Model (GCAM) to reflect the RYLs and analyze the effects on agricultural markets. We find that the changes (generally reductions) in O 3 precursor emissions in a reference scenario would reduce the agricultural damages, compared to present, for most of the regions, with a few exceptions including India, where higher future O 3 concentrations have large negative impacts on crop yields. The annual economic impact of O 3 driven losses from 2010 to 2080 are, in billion US dollars at 2015 prices ($B), 5.0–6.0, 9.8–18.8, 6.7–10.6 and 10.4–12.5 for corn, soybeans, rice and wheat, respectively, with the large losses for wheat and soybeans driven by their comparatively high responses to O 3. When O 3 effects are explicitly modelled as exogenous yield shocks in future periods, there is a direct impact in future agricultural markets. Therefore, the aggregated net present value (NPV) of crop production would be reduced around by $90.8 B at a global level. However, these changes are not distributed evenly across regions, and the net present market value of the crops would increase by up to $118.2 B (India) or decrease by up to $59.2 B (China). • Future ozone concentration levels will exceed established thresholds. • Annual economic damages of O 3 -related yield losses range from $34 B to $45 B. • USA, the European Union, India and China bear the majority of the economic damages. • Considering O 3 effects, cumulative NPV of crop production decreases around $90.8 B. [ABSTRACT FROM AUTHOR]

This paper deals with the temporal changes in the altitude distribution of tropospheric ozone (O 3) based on the measurements by balloon-borne O 3 -sondes during 2011–2014, conducted at the tropical, coastal site Thiruvananthapuram on the south west coast of India. This is the first study from this region addressing the highly dynamic nature of tropospheric O 3 profiles (in terms of their vertical structure and short-term changes) and attempting to categorise them based on 121 in-situ measured O 3 profiles. The tropospheric O 3 profiles could be categorised into four major groups namely (i) those with steady O 3 mixing ratio (ii) with increasing mixing ratio, (iii) with mid-tropospheric enhancement and (iv) with multiple layers/laminar nature. The causative mechanisms of these different categories were examined. The observed differences in the tropospheric O 3 distribution are attributed to meteorological conditions in particular the synoptic scale systems, long range transport, intrusion from stratosphere and photochemistry, most importantly, the effect of water vapour content. Water vapour and O 3 showed complex dependence with positive and negative association depending on the precursor levels and availability of water vapour. The altitudinal changes in O 3 also exhibited close association with those of potential temperature and equivalent potential temperature. An analysis of the seasonal characteristics of vertical distribution of tropospheric O 3 also carried out along with the altitude-dependent seasonal behaviour. In general, the total column O 3 estimated by the integration of O 3 -sonde retrieved profiles differed by about ±10% with those retrieved by satellite-based measurements. The TCO contributes to about 16% (34 DU) of the total column O 3 , with minimum of 9% in October and maximum of 27% on March. In general, the OMI retrievals under-estimates the O 3 -sonde derived TCO by 5–10 DU in all the seasons. • Dynamic nature of tropospheric O 3 profiles observations based on O 3 -sonde. • Dependence of O 3 on water vapour shows positive and negative correlation. • Amount of water vapour and precursors decide nature of water vapour dependence of O 3. • The seasonal variation of tropospheric O 3 is altitude-dependent. • Tropospheric column O 3 contributes about 16% of the total column O 3. [ABSTRACT FROM AUTHOR]