If we talk about Air Quality, India has reached an alarming state. Increased PM2.5 impacts air quality, environment, human health. World Health Organization’s recent report showed that 8.0 million deaths per year are seen due to bad air quality. This represents 6.7% of global disease burden which might be related to particulate matter. The exposure to ozone recorded 1.52 million premature deaths.
FACTORS FOR INCREASED PM2.5 CONCENTRATION
The combination of suspended solid particles and liquid droplets in air forms particulate matter. It also contains dust and soot. PM2.5 is ultra-fine inhalable particle having 2.5 micrometers of diameter and it can penetrate deep down the lungs causing respiratory diseases and ailments. It also comprises of metals & heavy metals ions (Cadmium, Nickel, Potassium, Copper), organic, inorganic compounds, allergens and many microbial compounds and Polycylic Aromatic Hydrocarbons (PAHs).
Increased air temperature during winter season and atmospheric inversions in Northern hemisphere increases PM2.5 concentration in air. During summer season, stationary air mass, forest fires and secondary aerosol formation increases PM2.5 concentration.
In Northern India, several factors contribute in increasing particulate matter concentration. Physical, chemical and meteorological factors affect the concentration of pm in environment. Physical and chemical factor inclusive of particle size, number, density, concentration in atmosphere affects the mobility (movement) of particle. Other than this, meteorological factors like wind speed, wind direction, weather conditions such as rainfall affects the processes of transport and fate of pm in environment.
In summers, residential energy contributes 62% to PM2.5 concentration and 70% in winters. Research Experiments have shown the concentration rises at night. India have reported 60 ug/m3 and 40 ug/m3 as 24 hour and annual PM2.5 concentration annually.
SOURCES OF PARTICULATE MATTER PM2.5 IN ENVIRONMENT
Presence and emergence of PM2.5 in environment is still debatable. Sources are the origin from where this pollutant enters the environment.
1. Natural Sources
Several natural events such as Rain, runoffs affect the mobility of PM 2.5. Rain water washes away the pollutant and changes its fate in environment. Forest Fires, Volcanic eruptions, natural calamities such as earthquakes lead to increase in Particulate Matter concentration. It has reduced rate of atmospheric descent which increases its persistent time in environment.
2. Industries and treatment plants
Processes of product production in Paper pulp industry, oil refineries, brick kilns, power plants and municipal waste treatment plants release PM 2.5 in environment.
Emissions from vehicles, coal combustion, burning of leaves & woods, agricultural activities, stubble burning, biomass burning and biofuel burning leads to increased particulate concentration. Gaseous emissions from power plants react in atmosphere and forms particulate matter.
4. Household activities and personal habits
PM 2.5 is also released from Tobacco smoking, candle burning, cooking activities like sauté, frying, irregular maintenance of kitchen chimney, kerosene heaters, gas stoves, fireplace operation etc. Other than this, construction activities increase the concentration of PM2.5.
IMPACTS OF PARTICULATE MATTER (PM2.5)
A. Impacts of PM2.5 on environment
Particulate Matter not only impacts human health but also environment. Environmental Impact of PM2.5 is seen as visibility reduction, acid rain, increased air pollution, material damage, ecosystem damage, reduced functioning of plants & trees, contaminated streams & oceans, decreased crop productivity and yield. Its dispersal is easy due to size and causes changed environmental fate.
1. Haze production
The haze reduces the visibility and increases chances of road accidents. Particulate Matter leaves a stain affecting the materialistic environment such as buildings, statues, monuments etc.
2. Soil fertility
Different chemical composition of particulate matter shows different effects. It also affects the soil fertility leading to reduction in crop yield and agricultural productivity.
3. Nutrient cycle
Particulate Matter interferes with nutrient cycling affecting the rhizosphere.
4. Plant Photosynthesis
Fine particles when settled over leaves block the penetration of sunlight into leaves and disrupt process of plant photosynthesis. Generation of Abrasions and radiative heat affects photosynthesis of plants due to layering of PM2.5 over leaves. This reduces photon flux reach towards photosynthetic tissues.
5. Deposition in water bodies
Settling of toxic PM2.5 containing heavy metals into water bodies including streams and oceans affects the marine and aquatic ecosystems. Several aquatic life forms die due to their reduced acidic tolerance. This also impacts human when they include contaminated aquatic food in their diet.
6. Disturbing ecosystems
Particulate Matter also disrupts the food chain and food web in ecosystem because of their shared dependencies, different toxicity tolerance and associated effects. Its concentration affecting the ecosystem has directly links to climate change.
B. Impacts of PM2.5 on human health
In epidemiological studies, severe health effects are linked with particulate matter having diameter of 2.5 microns. The effects of Particulate Matter in human body depend on its exposure duration and concentration.
Health effects of PM2.5 differ with age group, gender and race. Studies and research show white people, children and women are highly susceptible to being effected when exposed to it.
1. Penetration to respiratory system
Particulate Matter have tendency to carry toxic materials with themselves due to their reduced diameter and increased surface area. The small sized PM easily escapes from nostrils and penetrates deep down towards the bronchi and alveoli corroding alveolar wall in lungs.
According to WHO, in 2016, 4.2 million premature deaths were recorded because of PM2.5 exposure.
2. Increased Hospitalizations & absenteeism
Exposure to PM2.5 increases hospitalizations, visits to emergency room, absenteeism from schools and offices, especially in cases with pre-existing disorders, old people and children. Particulate Matter causes pneumonia and bronchitis.
3. Malignant effects
Exposure to Particulate Matter 2.5 shows malign effect in early life including respiratory, cardiovascular and prenatal disorders. This elevates infant mortality chances.
4. Human cornea and conjunctiva
Exposure to high concentration of PM2.5 leads to burning, itching and redness of eyes, allergic conjunctivitis. Laboratorial studies show it reduces survival of Human Corneal Epithelial Cells (HCEC) by triggering cell autophagy. It is also responsible for cell shrinkage.
5. Reduced antioxidants
Particulate Matter reduces antioxidants in human body. Hydroxyl ion induced oxidative stress damages the DNA. Teratogenesis, mutagenesis and carcinogenesis are induced by damaged DNA when not repaired in time.
6. Increased ROS species
Over production of reactive oxygen species (ROS) decreases antioxidant functioning of cells leading to lipid peroxidation on cell membrane elevating intracellular calcium (Ca2+) levels. Free radicals from PM2.5 induced free radical production oxidize lung cells and could be a prime cause of body injury caused by free radical peroxidation.
7. Reduced metabolic activities
PM2.5 triggers overexpression of inflammation related cytokines, autophagy and transcription factor genes causing inflammatory injuries in cells. Particulate Matter increases pathogenic adhesion and decreases antimicrobial activity, indigenous microflora, alveolar macrophages and natural killer cells.
8. Other related health effects
PM 2.5 causes cerebrovascular disorder, mental health, sneezing, coughing, irritation in eyes, nose & throat, skin allergies, asthma, Cardiovascular Obstructive Pulmonary Disorder (COPD), suffocation, cardiac arrhythmia, cancer, genotoxicity, cancer, inflammation. Studies show it can even cause diabetes mellitus, reduced birth weights and premature deaths. It causes cardiovascular and pulmonary diseases leading to mortality and morbidity increment.
22 INDIAN CITIES OUT OF 30 MOST POLLUTED CITIES IN WORLD
Construction activities, automobile number (increases with increase in population), industrialization and urbanization in Asian metropolitan areas contribute largely towards PM2.5 pollution.
According to WHO, 91% of people live in places having air quality index higher than the prescribed standards. 91% of premature deaths are seen in Low & Middle Income Countries.
According to paper published in Lancet Planetary Health by India State Level Disease Burden Initiative, 18% of total deaths in India were due to air pollution in 2019.
American Cancer Society’s cohort study showed 15-27% increase in mortality of lung cancer with 10ug/m3 of increase in PM2.5 concentration.
According to a recent 2021 report released by Swiss Organization, 22 Indian cities holds rank in 30 most polluted cities in world.
Ghaziabad ranked second with 106.6 ug/m3 of average annual Particulate Matter 2.5 concentration after Hotan, China. Other Indian cities securing rank were Bulandshahr, Bisrakh, Jalalpur, Bhiwadi, Noida, Greater Noida, Kanpur, Lucknow, Delhi, Faridabad, Meerut, Hisar, Jind, Haryana, Agra, Fatehabad, Muzaffarnagar, Muzaffarpur, Gurgaon, Bandhwari, Yamuna Nagar, Rohtak and Dharuhera. Most of these cities are in North Indian states inclusive of Uttar Pradesh, Haryana and Rajasthan.
STUBBLE BURNING’S ADDITION TO PARTICULATE MATTER CONCENTRATION IN DELHI
Northern region of India falls on Indo Gangetic Plain. Pre monsoon (April to May) and post monsoon (October to November) period is when residents of North India experience heavy air pollution. In 2020, Nair M., et al reported India as second highest aerosol emissions contributor solely because of Stubble burning. Stubble burning and its association with transportation emissions have direct and indirect impact on both human health and climate change. In the year 2019, the value of Air Quality Index (AQI) in Delhi recorded was 487. Ghaziabad recorded 493 whereas in Greater Noida it was 480 which have deadly and hazardous impact on human health.
Stubble burning is burning of straw stubble from rice and wheat harvest and is hazardous for Delhi and its residents. Stubble burning causes increased particulate matter concentration in atmospheric air which can penetrate deep inside the lungs raising lung cancer chances by 36%.
India shares 26.2 % in total global Disability Adjusted Life Years (DALY). Punjab, Haryana, Uttar Pradesh and Rajasthan from Northern India reported highest DALY. A report from World Bank showed that Biomass Burning contributes to 9-28 % of PM2.5 in Delhi, 23-29 % in Mumbai, 24% in Chandigarh and 37-70 % in Kolkata. Particles released from stubble burning are stagnant at 2 km height higher than the stubble region and these particles are dispersed by wind to higher heights at 3000m towards the side of Delhi. The stagnation of these particles could be due to reduced wind speed and direction.
Emissions from burned stubble:
With stubble burning, Carbon monoxide (CO), carbon dioxide (CO2), Nitrogen oxides (NOx), Sulfur oxides (SOx), methane (CH4) and PM10 and PM2.5 are released. In India, every year 342 MT of stubble is generated out of which 34% and 22% is produced by rice and wheat respectively. 23.86 % of 342 MT is burned immediately after harvest on fields in open environment.
IARI (Indian Agricultural Research Institute) report showed that each year 14 MT out of 22 MT of rice stubble is burned. Haryana and Punjab are responsible for 48% of total rice stubble burning. In 2011, Sahai et al reported that burning of 63 MT stubble is responsible for 3.4 MT of CO, 0.1 MT of NOx, 91 MT of CO2, 0.6 MT of CH4 and 1.2 MT of Particulate Matter release in air.
46.5% of increase in stubble burning was reported by Economic Times from Punjab and reduction by 28.6% from Haryana. In 2019, Punjab reported 52,225 active fires from stubble burning which increased by 24.312 fires in 2020 making it 76.537 active fires. This leads to increase in particulate matter concentration.
MEASURES TO REDUCE PARTICULATE MATTER 2.5
Each and every contribution counts when it comes to reduce pollution. There are some of the measures that individuals can adopt to reduce PM2.5 pollution.
- If you do smoke, quit smoking because it hikes Particulate Matter 2.5 concentration.
- Avoid continuous burning of woods, candles and fireplaces.
- Do not use vacuum cleaners without HEPA filters.
- Avoid using personal transport every time, and planning many trips
- Switch to renewable and clean sources of energy in domestics namely solar and wind energy.
- Give use of generators in houses a miss.
- Switching off the vehicles when waiting on red lights.
- Stop getting unnecessary renovations and constructions at houses.
A major step to reduce particulate matter is to stop stubble burning. Instead stubble when managed duly can bring in various economic benefits. Stubble produce after crop harvest have ability of increase soil fertility. Hence, its application will make the soil more fertile. Stubble is a good source of energy and can be applied in power plants. Stubble based raw material is beneficial in paper and pulp industry. In biofuel production stubble is used as biomass. Stubble is easy to convert into compost or biochar.
A study given by Upadhyay A., et al in 2018 showed that emissions from transport, industrial and energy sector when mitigated completely saves 92,380 premature lives. Emissions from residential sectors when mitigated completely can save 378,295 lives. This accounts for 95% of uncertainty intervals.