Airing 'clean air' in Clean India Mission

Landscape assessment of the cities in the state of Maharashtra: first step towards air quality management (AQM) and strategic implementation of mitigation plans

OBJECTIVE OF THE STUDY

This study aims to understand the need for landscape assessment of the 18 non-attainment cities in the state of Maharashtra, to understand and rank the cities according to the need and necessity for strategic implementation of air quality management. This air quality management is a National Clean Air Programme initiative to curb the air pollution level in all the highly polluted Indian cities by 20-30% till 2024.

METHODOLOGY

The ranking and selection of the cities consisted of a two-phase approach including (a) desk research and (b) field interventions and stakeholders' consultations. The first phase included (a_i) review of 18 non-attainment cities in Maharashtra, (a_ii) identification of suitable indicators to inform prioritisation during the ranking process, (a_iii) data collection and analysis of the indicators and (a_iv) the ranking of the 18 non-attainment cities in Maharashtra. The second phase, i.e. field interventions included (b_i) Mapping of stakeholders and field visits, (b_ii) the consultations with the stakeholders, (b_iii) information and data collection and (b_iv) ranking and selection of cities. On analysing the score obtained from both the approaches a ranking of all the cities is done accordingly.

RESULTS AND DISCUSSION

The screening of cities from the first phase gave a possible list of 8 cities-Aurangabad, Kolhapur, Mumbai, Nagpur, Nashik, Navi Mumbai, Pune, Solapur. Further, the second round of analysis involving field interventions and stakeholder consultations was done within the 8 cities to find out the most suitable list of two to 5 cities. The second research analysis gave Aurangabad, Kolhapur, Mumbai, Navi Mumbai and Pune. A more granular stakeholder consultation resulted in the selection of cities like Navi Mumbai and Pune as the cities where implementation of new strategies seemed feasible.

INTERVENTION AND ACTIVITIES

New strategic interventions like (a) strengthen the clean air ecosystem/institutions, (b) air quality monitoring and health impact assessment, and (c) skill development to ensure the long-term sustainability of initiatives planned for the cities.

Analysis and Variation of the Maiac Aerosol Optical Depth in Underexplored Urbanized Area of National Capital Region, India

Aerosol monitoring is the emerging application field of satellite remote sensing. As a satellite-based indicator of aerosol concentration, aerosol optical depth (AOD) can aid in assessing the crucial effects of aerosols on the global environment. Among various satellite-based aerosol product, Moderate Resolution Imaging Spectroradiometer (MODIS) Collection 6 (C6), Multiangle Implementation of Atmospheric Correction (MAIAC) aerosol product (1 km resolution) has still untapped potential in Indian regions. Considering the importance of regional validation of such high-resolution aerosol product, the present study attempts to fill this gap by validating MAIAC aerosol estimates (AODMAIAC) in highly polluted districts (Faridabad, Ghaziabad, Gautam Budh Nagar, Gurugram) of National Capital Region (NCR) with heavy aerosol loading using limited AErosol RObotic NETwork (AERONET) observations obtained from AERONET sites at Amity University (AU) and Gual Pahari (GP). Such evaluation of satellite-retrieved aerosol product with ground data confirms its practicality based on retrieval errors (Expected Error (EE) values (EE = 0.05 + 15 %*AOD) (EE: 78.85 % at AU, 73.58 % at GP), root mean square error (RMSE) values (RMSE: 0.15 at AU, 0.24 at GP), and correlation coefficient (R) values (R: 0.86 at AU, 0.73 at GP). The seasonal variation in AOD over the study area from 2010-2019 reveals increasing trend of AOD in the monsoon and post-monsoon season due to natural and anthropogenic factors. In addition to contributing to a holistic assessment of MAIAC aerosol estimates as a recent, high-resolution aerosol product, present results provide a basis for further research into NCR aerosols.

Source apportionment and health risk assessment of airborne particulates over central Indo-Gangetic Plain

Sources of airborne particulates (PM₁₀) were investigated in two contrasting sites over central Indo-Gangetic Plain (IGP), one representing a rural background (Mirzapur) and another as an urban pollution hotspot (Varanasi). Very high PM₁₀ concentration was noted both in Varanasi (178 ± 105 μgm^-3; N:435) and Mirzapur (131 ± 56 μgm^-3; N:169) with 72% and 62% of monitoring days exceeded the national air quality standard, respectively. Particulate-bound elements contribute significant proportion of PM₁₀ mass (15%-18%), with highest contribution from Ca (7%-10%) and Fe (2%-3%). Besides, presence of Zn (1%-3%), K (1%-2%) and Na (1%-2%) was also noted. Water-soluble ionic species contributed 15%-19% of particulate mass, primarily by the secondary inorganic aerosols (SIA). Among the SIA, sulphate (5%-7%) and nitrate (4%) were prominent, contributing 59%-62% of the total ionic load, especially in winter. Particulate-bound metallic species and ions were selectively used as signatory molecules and source apportionment of PM₁₀ was done by multivariate factor analysis. UNMIX was able to extract particulate sources in both the locations and crustal resuspensions (dust/-soil) were identified as the dominant source contributing 57%-63% of PM₁₀ mass. Secondary aerosols were the second important source (17%-23%), followed by emissions from biomass/-refuse burning (10-19%). Transport of airborne particulates from upper IGP by prevailing westerly were identified as the important contributor of particulates, especially during high particulate loading days. Health risks associated to particulate-bound toxic metal exposure were also assessed. Non-carcinogenic health risk was within the permissible limit while there is possibility of elevated risk for PM₁₀-bound Cr and Cd, if adequate control measures are not in place.

Vertical distribution of smoke aerosols over upper Indo-Gangetic Plain

Attenuated backscatter profiles retrieved by the space borne active lidar CALIOP on-board CALIPSO satellite were used to measure the vertical distribution of smoke aerosols and to compare it against the ECMWF planetary boundary layer height (PBLH) over the smoke dominated region of Indo-Gangetic Plain (IGP), South Asia. Initially, the relative abundance of smoke aerosols was investigated considering multiple satellite retrieved aerosol optical properties. Only the upper IGP was selectively considered for CALIPSO retrieval based on prevalence of smoke aerosols. Smoke extinction was found to contribute 2-50% of the total aerosol extinction, with strong seasonal and altitudinal attributes. During winter (DJF), smoke aerosols contribute almost 50% of total aerosol extinction only near to the surface while in post-monsoon (ON) and monsoon (JJAS), relative contribution of smoke aerosols to total extinction was highest at about 8 km height. There was strong diurnal variation in smoke extinction, evident throughout the year, with frequent abundance of smoke particles at lower height (<4 km) during daytime compared to higher height during night (>4 km). Smoke injection height also varied considerably during rice (ON: 0.71 ± 0.65 km) and wheat (AM: 2.34 ± 1.34 km) residue burning period having a significant positive correlation with prevailing PBLH. Partitioning smoke AOD against PBLH into the free troposphere (FT) and boundary layer (BL) yield interesting results. BL contribute 36% (16%) of smoke AOD during daytime (nighttime) and the BL-FT distinction increased particularly at night. There was evidence that despite travelling efficiently to FT, major proportion of smoke AOD (50-80%) continue to remain close to the surface (<3 km) thereby, may have greater implications on regional climate, air quality, smoke transport and AOD-particulate modelling.

Experiences with the Mass Distribution of LPG Stoves in Rural Communities of Ghana

Household air pollution (HAP) is a leading cause of morbidity and mortality worldwide. To limit HAP exposure and environmental degradation from biomass fuel use, the Government of Ghana promotes liquefied petroleum gas (LPG) use in rural Ghana via the Rural LPG program (RLP). We assessed the experiences of the RLP in 2015, 2 years after its launch. A mixed methods approach was used involving Focus Group Discussions (19) and in-depth interviews (25). In addition, a survey questionnaire was administered to elicit socio-demographic characteristics, household cooking practices and stove use patterns of 200 randomly selected respondents. At about 9 months after LPG acquisition, < 5% of LPG beneficiaries used their stoves. Some of the reasons ascribed to the low usage of the LPG cookstoves were financial constraints, distance to LPG filling point and fear of burns. Community members appreciate the convenience of using LPG. Our results underscore a need for innovative funding mechanisms contextualized within an overall economic empowerment of rural folks to encourage sustained LPG use. It emphasizes the need for innovative accessibility interventions. This could include establishing new LPG filling stations in RLP beneficiary districts to overcome the barriers to sustained LPG use.

Airborne particulate in Varanasi over middle Indo-Gangetic Plain: variation in particulate types and meteorological influences

The variation in particulate mass and particulate types (PM_2.5 and PM₁₀) with respect to local/regional meteorology was analyzed from January to December 2014 (n = 104) for an urban location over the middle Indo-Gangetic Plain (IGP). Both coarser (mean ± SD; PM₁₀ 161.3 ± 110.4 μg m^-3, n = 104) and finer particulates (PM_2.5 81.78 ± 66.4 μg m^-3) revealed enormous mass loading with distinct seasonal effects (range: PM₁₀ 12-535 μg m^-3; PM_2.5 8-362 μg m^-3). Further, 56% (for PM_2.5) to 81% (for PM₁₀) of monitoring events revealed non-attainment national air quality standard especially during winter months. Particulate types (in terms of PM_2.5/PM₁₀ 0.49 ± 0.19) also exhibited temporal variations with high PM_2.5 loading particularly during winter (0.62) compared to summer months (0.38). Local meteorology has clear distinguishing trends in terms of dry summer (March to June), wet winter (December to February), and monsoon (July to September). Among all the meteorological variables (average temperature, rainfall, relative humidity (RH), wind speed (WS)), temperature was found to be inversely related with particulate loading (r_PM10 -0.79; r_PM2.5 -0.87) while RH only resulted a significant association with PM_2.5 during summer (r_PM10 0.07; r_PM2.5 0.55) and with PM₁₀ during winter (r_PM10 0.53; r_PM2.5 0.24). Temperature, atmospheric boundary layer (ABL), and RH were cumulatively recognized as the dominant factors regulating particulate concentration as days with high particulate loading (PM_2.5 >150 μg m^-3; PM₁₀ >260 μg m^-3) appeared to have lower ABL (mean 660 m), minimum temperature (<22.6 °C), and high RH (∼79%). The diurnal variations of particulate ratio were mostly insignificant except minor increases during night having a high wintertime ratio (0.58 ± 0.07) over monsoon (0.34 ± 0.05) and summer (0.30 ± 0.07). Across the region, atmospheric visibility appeared to be inversely associated with particulate (r_PM2.5 -0.84; r_PM10 -0.79) for all humid conditions, while at RH ≥80%, RH appeared as the most dominant factor in regulating visibility compared to particulate loading. The Lagrangian particle dispersion model was further used to identify possible regions contributing particulate loading through regional/transboundary movement.

Fine particulates over South Asia: Review and meta-analysis of PM2.5 source apportionment through receptor model

Fine particulates (PM_2.5) constitute dominant proportion of airborne particulates and have been often associated with human health disorders, changes in regional climate, hydrological cycle and more recently to food security. Intrinsic properties of particulates are direct function of sources. This initiates the necessity of conducting a comprehensive review on PM_2.5 sources over South Asia which in turn may be valuable to develop strategies for emission control. Particulate source apportionment (SA) through receptor models is one of the existing tool to quantify contribution of particulate sources. Review of 51 SA studies were performed of which 48 (94%) were appeared within a span of 2007-2016. Almost half of SA studies (55%) were found concentrated over few typical urban stations (Delhi, Dhaka, Mumbai, Agra and Lahore). Due to lack of local particulate source profile and emission inventory, positive matrix factorization and principal component analysis (62% of studies) were the primary choices, followed by chemical mass balance (CMB, 18%). Metallic species were most regularly used as source tracers while use of organic molecular markers and gas-to-particle conversion were minimum. Among all the SA sites, vehicular emissions (mean ± sd: 37 ± 20%) emerged as most dominating PM_2.5 source followed by industrial emissions (23 ± 16%), secondary aerosols (22 ± 12%) and natural sources (20 ± 15%). Vehicular emissions (39 ± 24%) also identified as dominating source for highly polluted sites (PM_2.5>100 μgm^-3, n = 15) while site specific influence of either or in combination of industrial, secondary aerosols and natural sources were recognized. Source specific trends were considerably varied in terms of region and seasonality. Both natural and industrial sources were most influential over Pakistan and Afghanistan while over Indo-Gangetic plain, vehicular, natural and industrial emissions appeared dominant. Influence of vehicular emission was found single dominating source over southern part while over Bangladesh, both vehicular, biomass burning and industrial sources were significant.