Decline in PM2.5 Concentrations over Major Cities Around the World Associated with COVID-19

The COVID-19 started from Wuhan city in China, slowly spread across the globe after December 2019. Due to movement of people from one city to other cities, one country to other countries, infection spreads and COVID-19 became a pandemic. Efforts were made at local, regional and national levels to lockdown the movement of people and to keep infected one in quarantine or isolation to stop the spread of COVID-19. The traffic, market and small industries were closed, as a result pronounced decline in the concentrations of particulate matters (PM) were observed. Normally these sources contribute to the high concentrations of particulate matters (PM2.5) which represents air quality of a location. In this short communication, we present analysis of PM2.5 of major cities (New York, Los Angeles, Zaragoza, Rome, Dubai, Delhi, Mumbai, Beijing and Shanghai) around the world suffered severely with the COVID-19. Our analysis shows decline in PM2.5 concentration due to lockdown, mainly due to less movement of people to keep “social distancing” to control the spread of CORONA-19. The low concentrations of PM2.5 reflect the efforts made in the cities to curb the spread of infection, that improve air quality

Increasing Health Threat to Greater Parts of India Due to Crop Residue Burning

Rice crop residue burning during mid-October to November every year is becoming a serious health threat because of increased burning by farmers in the states of Punjab, Haryana, and western Uttar Pradesh in northern India. Crop residue burning started in the late 1980s with the start of mechanised harvesting in Punjab. Farmers found burning to be an economical way of cleaning crop stalk residues that are left over by mechanised harvesters. In doing so, farmers ignore the impact of this practice on health and air quality in the cities located in the Indo-Gangetic Plains. In the winter season, the severity of this problem increases as dispersion of smoke plumes is slowed down because of cold temperatures, whereas during the summer season the problem does not exist because of fast dispersion of plumes from burning. The practice of crop residue burning that started in Punjab has slowly spread to other adjoining states in northern India. We have found that the impact of crop residue burning on air quality is not restricted to cities in the Indo-Gangetic Plains alone, but is spreading to the far eastern parts of the Indo-Gangetic Plains and over central and southern parts of India, including parts of Bihar, Jharkhand, West Bengal, Madhya Pradesh, Chhattisgarh, Odisha, Telangana, and Maharashtra. We used diverse climate datasets derived from different NASA space platforms as well as global climate models and ground stations for our analysis

Impact of Lockdown on Air Quality in India During COVID-19 Pandemic

First time in India, total lockdown was announced on 22 March 2020 to stop the spread of COVID-19 and the lockdown was extended for 21 days on 24 March 2020 in the first phase. During the total lockdown, most of the sources for poor air quality were stopped in India. In this paper, we present an analysis of air quality (particulate matter-PM2.5, Air Quality Index, and tropospheric NO2) over India using ground and satellite observations. A pronounced decline in PM2.5 and AQI (Air Quality Index) is observed over Delhi, Mumbai, Hyderabad, Kolkata, and Chennai and also a declining trend was observed in tropospheric NO2 concentration during the lockdown period in 2020 compared with the same period in the year 2019. During the total lockdown period, the air quality has improved significantly which provides an important information to the cities’ administration to develop rules and regulations on how they can improve air quality

Coupling between Land–Ocean–Atmosphere and Pronounced Changes in Atmospheric/Meteorological Parameters Associated with the Hudhud Cyclone of October 2014

India is vulnerable to all kinds of natural hazards associated with land, ocean, biosphere, atmosphere, and snow/glaciers. These natural hazards impact large areas and the population living in the affected regions. India is surrounded by ocean on three sides and is vulnerable to cyclonic activities. Every year cyclones hit the east and west coasts of India, affecting the population living along the coasts and infrastructure and inland areas. The extent of the affected inland areas depends on the intensity of the cyclone. On 12 October 2014, a strong cyclone “Hudhud” hit the east coast of India that caused a high degree of devastation along the coast. The impact of this cyclone was seen up to the Himalayan region. Detailed analysis of satellite and ground data show a strong coupling between land-ocean-atmosphere associated with the Hudhud cyclone. The contrast between land and ocean temperature was found to be closely related with the formation of the cyclone in the ocean and its movements towards land. Pronounced changes in the ocean, land, atmospheric, and meteorological parameters with the development of the cyclone and its landfall have been observed. Changes in total column ozone (TCO), relative humidity (RH), and volume mixing ratio of CO (CO VMR), water mixing ratio (H2O MMR), surface latent heat flux (SLHF), and aerosol optical properties derived from satellite data show characteristic behavior of the Hudhud cyclone

Impact of Deadly Dust Storms (May 2018) on Air Quality, Meteorological, and Atmospheric Parameters Over the Northern Parts of India

The northern part of India, adjoining the Himalaya, is considered as one of the global hot spots of pollution because of various natural and anthropogenic factors. Throughout the year, the region is affected by pollution from various sources like dust, biomass burning, industrial and vehicular pollution, and myriad other anthropogenic emissions. These sources affect the air quality and health of millions of people who live in the Indo‐Gangetic Plains. The dust storms that occur during the premonsoon months of March–June every year are one of the principal sources of pollution and originate from the source region of Arabian Peninsula and the Thar desert located in north‐western India. In the year 2018, month of May, three back‐to‐back major dust storms occurred that caused massive damage, loss of human lives, and loss to property and had an impact on air quality and human health. In this paper, we combine observations from ground stations, satellites, and radiosonde networks to assess the impact of dust events in the month of May 2018, on meteorological parameters, aerosol properties, and air quality. We observed widespread changes associated with aerosol loadings, humidity, and vertical advection patterns with displacements of major trace and greenhouse gasses. We also notice drastic changes in suspended particulate matter concentrations, all of which can have significant ramifications in terms of human health and changes in weather pattern

Dynamic Characteristics of Aerosol Optical Properties over Dibrugarh City in the North-Eastern Indian Region during 2018–2021

Aerosols play an important role in the earth\u27s environment across the globe through their involvement in various earth system cycles. The change in the aerosol properties may cause short and long-term impacts, the knowledge of such changes is useful in the estimation of the pollution sources of any region. We have carried out the analysis of the aerosols\u27 optical and radiative properties using AERONET station data from 2018 to 2021 in Dibrugarh City. The higher Aerosol Optical Depth (AOD) values during winter and pre-monsoon months indicate high anthropogenic activities, and biomass burning in Dibrugarh. The impact of various sources and daily meteorological parameters help in understanding the diurnal variations of the AOD, Ångström Exponent (AE), and column water (CW). Fine aerosol fractions dominate the aerosol volume, but sometimes the long-range transport of dust affects aerosol properties during pre-monsoon months (MAM). MODIS-derived AOD and AERONET AOD values show a good correlation, with R2 = 0.68. The highest volume of the aerosols reaches up to 0.11 µm3 µm–2 during pre-monsoon months, whereas it lies below 0.05 µm3 µm–2 in other seasons. SSA values indicate the presence of scattering aerosols but in 2020, a sudden decline in the SSA values shows a strong rise in the absorbing aerosols. Throughout the study period (2018–2021), the positive radiative forcing indicates a rise in atmospheric heating

Changes in Atmospheric, Meteorological, and Ocean Parameters Associated with the 12 January 2020 Taal Volcanic Eruption

The Taal volcano erupted on 12 January 2020, the first time since 1977. About 35 mild earthquakes (magnitude greater than 4.0) were observed on 12 January 2020 induced from the eruption. In the present paper, we analyzed optical properties of volcanic aerosols, volcanic gas emission, ocean parameters using multi-satellite sensors, namely, MODIS (Moderate Resolution Imaging Spectroradiometer), AIRS (Atmospheric Infrared Sounder), OMI (Ozone Monitoring Instrument), TROPOMI (TROPOspheric Monitoring Instrument) and ground observations, namely, Argo, and AERONET (AErosol RObotic NETwork) data. Our detailed analysis shows pronounced changes in all the parameters, which mainly occurred in the western and south-western regions because the airmass of the Taal volcano spreads westward according to the analysis of airmass trajectories and wind directions. The presence of finer particles has been observed by analyzing aerosol properties that can be attributed to the volcanic plume after the eruption. We have also observed an enhancement in SO2, CO, and water vapor, and a decrease in Ozone after a few days of the eruption. The unusual variations in salinity, sea temperature, and surface latent heat flux have been observed as a result of the ash from the Taal volcano in the south-west and south-east over the ocean. Our results demonstrate that the observations combining satellite with ground data could provide important information about the changes in the atmosphere, meteorology, and ocean parameters associated with the Taal volcanic eruption

Changes in the Flood Plains and Water Quality Along the Himalayan Rivers After the Chamoli Disaster of 7 February 2021

The Himalayan regions are vulnerable to all kinds of natural hazards. On 7 February 2021, a deadly disaster occurred near the Tapovan, in Uttarakhand, Himalayas. During the event, large volume of debris along with broken glacial fragments flooded the Rishi Ganga River and washed away the nearby hydropower plants (Rishi Ganga and Tapovan), which was revealed from detailed analysis of multi spectral and bi-temporal satellite data. We present the impact of the Chamoli disaster on the flood plains and water quality of Himalayan rivers, Rishi Ganga near Tapovan, Alaknanda near Srinagar and Ganga near Haridwar and Bijnor. We used four locations along four sections of Himalayan rivers and have analysed various indices, modified normalized difference water index, normalized difference chlorophyll index, and normalized difference turbidity index, to study the changes in water quality and flood plains. On comparison of the spectral and backscattering coefficients derived from Sentinel-2 optical and Sentinel-1 synthetic aperture radar data, changes in the water quality and flood plains of the rivers were found

Chamoli Disaster: Pronounced Changes in Water Quality and Flood Plains Using Sentinel Data

The Himalayan rivers are vulnerable to devastating flooding caused by landslides and outbreak of glacial lakes. On 7 February 2021, a deadly disaster occurred near the Rishi Ganga Hydropower Plant in the Rishi Ganga River, killing more than 100 people. During the event, a large volume of debris and broken glacial fragments flooded the Rishi Ganga River and washed away the Rishi Ganga Hydropower plant ongoing project. This study presents the impact of the Chamoli disaster on the water quality of Rishi Ganga River in upstream near Tapovan and Ganga River in downstream near Haridwar through remote sensing data. Five points have been used at different locations across the two study areas and three different indices were used such as Normalized difference water index (NDWI), Normalized difference turbidity Index (NDTI), and Normalized difference chlorophyll index (NDCI), to analyze changes in water quality. Spectral signatures and backscattering coefficients derived from Sentinel-2 Optical and Sentinel-1 Synthetic-aperture radar (SAR) data were also compared to study the changes in water quality. It was evident from the water quality indices and spectral signatures that the flood plains changed significantly. Using spectral signatures and different indices, the water level in the Chilla dam canal near Haridwar was found to decreased after the Chamoli disaster event as the flood gates were closed to stop the deposit of sediments in the canal. Results suggest changes in water quality parameters (turbidity, chlorophyll concentration, NDWI) at the five locations near the deadly site and far away at Haridwar along the Ganga River. This study is a preliminary qualitative analysis showing changes in river flood plain and water quality after the Chamoli disaster

Sources of Atmospheric Pollution in India

India with 28 states and 8 union territories has diversified weather conditions, and is a home to 1.389 billion people. India is surrounded by the Bay of Bengal in the east, the Arabian Sea in the west, and the Indian Ocean in the south. In the northern part, the Indo-Gangetic Plain (IGP) lies between the Indian shield and the Himalayan region. The IGP is one of the agriculturally productive regions with fertile land and good groundwater resources. About 900 million people live in the IGP, the westerly winds are dominant in the northern parts, which brings pollutants from the neighboring countries and the outflow from the IGP reaches over Bangladesh and beyond. The outflow of pollutants also reaches toward the Himalayan regions and the pollutants especially at the time of forest fires impact the IGP region. The northern flank of India is surrounded by the towering Himalayas. The western part is adjacent to the neighboring country Pakistan, and between IGP and the eastern side, Bangladesh is located. In the northern part of India including IGP, all the four seasons (winter, summer, monsoon, and premonsoon) with contrasting weather conditions are observed. The region experiences extreme weather conditions, and all the major cities are known for high atmospheric pollution and poor air quality throughout the year and contrasting seasonal differences. In this chapter, an overview of atmospheric pollution and poor air quality and their dynamics are presented.https://digitalcommons.chapman.edu/sees_books/1018/thumbnail.jp