29 Air Quality and Greenhouse Gases

Dhanya M S

Learning Objectives

After reading this chapter the student will be able to understand

• Urban and indoor air pollutants and its types
• Major greenhouse gases and its emissions to atmosphere
• Relationship between air quality and green house gases
• How it is related with global warming and climate change
• Air quality monitoring and measures to mitigate air pollution
• Mitigation measures for reducing greenhouse gases emissions

1. Introduction

The air pollution is identified as one of the major environmental health hazard in the world and WHO reported that indoor and outdoor air pollution was responsible for around 3.7 million deaths of people aged below 60 years in 2012. It causes a significant impact on human health and the environment. Rapid urbanization and industrialization has resulted in deterioratingboth outdoor and indoor air quality in major cities, especially in developing countries. The air pollution is linked with increase in greenhouse gas emissions to the atmosphere causing global warming. So the air quality issues and greenhouse gases are of concern and there is increased seriousness about addressing this issue.

The air pollution is phenomenon of modification of the natural characteristics of atmosphere by addition of chemical, physical and biological agents and making it harmful for life. It is classified into outdoor and indoor air pollution and quality of air varies with these two types of pollution.

2. What are causes of urban outdoor air pollution?

The major source of primary and secondary pollutants is of urban origin. The urban air is a complex mixture of toxic gases and particulates, the major source is combustion of fossil fuels. Both mobile sources and stationary sources make significant contributions to urban outdoor air pollution.

The urban air pollution is mainly attributed by following sources Transportation sector The pollutant emissions mainly depend on exhaust fumes from vehicles. The urban air pollution is from

• – large number of vehicles
• – use of diesel powered vehicles
• – use of outdated vehicles
• – huge number of motor cycles/three wheelers on road
• – low quality of fuel
• – fuel adulteration in vehicles

Private and commercial vehicles account for 66.28% of the total consumption of diesel. Low standards for vehicle emissions and fuel have increased levels of oxides of Nitrogen (NOx) and Sulphur (SOx) in the air. According to a report released by the International Council on Clean Transportation, diesel vehicles contributes to 56% of all PM emissions and 70% of all Nitrogen Oxides (NOx) emissions from on-road vehicles in India.

Industrial sector:

The stationary sources include emissions from manufacturing facilities (i.e. factories) and power generation (i.e. smoke stacks of coal fired power plants). The emissions from industries increased by

• – usage of poor technology and machineries
• – no means for emission control
• – Inadequate infrastructure

Waste sector: The emissions mainly due to

• – Poor management
• – Inefficient incineration techniques

These sources emit the primary and secondary pollutants such as particulate matters (PM10, PM2.5), Lead (Pb), Sulphur dioxide (SO2), Oxides of nitrogen (NOx), Ozone (O3), Hydro carbons (HCs), Carbon monoxide (CO), Hydrogen fluoride (HF), Heavy metals (e.g. Pb, Hg, Cd etc.). The major sources of particulate matter contributing to urban air pollution are traffic (25%), combustion and agriculture (22%), domestic fuel burning (20%), natural dust and salt (18%), and industrial activities (15%).

3. Indoor air pollution

Indoor air quality refers to the quality of air within and around buildings and structures. WHO ranked indoor air pollution as the 8th most important risk factor responsible for 2.7 per cent of global burden of diseases (WHO, 2002). The levels of indoor air pollution depend on factors such as presence of indoor sources and emission rate, ventilation rate, penetration of outdoor pollutants to indoor environment and pollutant sink or removal rate on indoor surfaces.

• The sources of indoor air pollution are grouped into four categories
• Combustion pollutants
• Non combustion pollutants
• Hazardous chemicals or materials applied indoors Biological agents

3.1. The combustion pollutants are those pollutants emitted from domestic combustion and tobacco smoke.

3.1.1 Domestic combustion

Smoke from fuel burned indoors mainly from cooking and space heating contains pollutants such as fine particulate matter (PM), VOCs, CO and carcinogenic PAHs. Solid fuels such as wood, agricultural wastes, cattle dung or low quality coal are used in rural and peri-urban areas. The cooking stoves with low efficiency generate higher emissions of incomplete combustion products. As per Census 2011, 87% of rural households and 26% of urban households depend on biomass for cooking. Burning of biomass is a leading cause of indoor air pollution and is responsible for respiratory and pulmonary health issues in approximately 400 million Indians.

3.1.2 Tobacco smoke

Environmental Tobacco Smoke (ETS) is a complex mixture of toxic pollutants like fine particles, nicotine, nitrosamines, PAHs, CO, NOx etc. ETS causes adverse health effects also to passive smokers or exposed non-smokers.The ban on smoking in public places is practiced in many countries.

3.2  Non-combustion pollutants are pollutants released from building materials

The pollutants released without combustion mainly from airtight buildings with poor ventilation occur commonly in modern offices and urban houses. The sick building syndrome is reported from many developed and developing countries. Major indoor air pollutants of non-combustible group are chemical vapors, radon and asbestos.

3.2.1.   Chemical vapor

The various building materials, furnishings, paints, varnishes, solvents, adhesives, office equipments, etc. that contain organic chemicals were released into indoor environment either in use or stored. The released chemical vapors exist in vapor phase be absorbed or adsorbed onto indoor materials like carpets, gypsum boards serve as temporary sinks and off- gas the vapors slowly and results in chronic exposure. Formaldehyde based adhesives like particle board, plywood paneling and medium density fibre board used indoors release formaldehyde which cause acute and chronic health effects.

3.2.2.   Radon

It is a gas produced in the radioactive decay process of radium which is found almost in all soil and rocks. This gas enters the homes through dirt floors, cracks in concrete walls and floors, floor drains and sumps. The radon produce a series of short lived progenies while undergoing radioactive decay and most of them attached to particles present in indoor air. These particles when inhaled deposited in lungs and can increase the risk of lung cancer. WHO (2009) recommends a reference level of 2.7 PCi/L for radon to minimize the exposure health hazard.

3.2.3.   Asbestos

It is commercial name of six naturally occurring fibrous minerals (chrysotile, actinolite, amosite, anthophyllite, crocidolite and tremolite) belonging to two groups namely serpentine and amphibole. The commercially used asbestos is chrysolite (white asbestos), crocidolite (blue asbestos) and amosite (brown asbestos). The white asbestos comprised 90 per cent of world commercial asbestos but the most dangerous asbestos is crocidolite. The most dangerous asbestos fibres which are too small to be visible are inhaled and accumulated in lungs. The diseases associated with exposure to asbestos are lung cancer, mesothelioma, asbestosis and non-malignant pleural disease. This asbestos exposure is related with occupational exposures to high concentrations.

3.3.  Hazardous chemicals used indoors: Pesticides

The pesticides are used in and around houses to control insects, termites, rodents, fungi and microbes.The levels of many pesticides found high in indoor air despite the bans on their use as it belong to persistent organic pollutant (POP) pesticides. The health concerns associated with exposure of pesticides indoors include both acute toxic effects that occur immediately after application and potential carcinogenic effect of some pesticides. The aerosol spray which is commonly used method of pesticide application and storing of pesticide containers in living rooms contribute to high exposure of these chemicals.

3.4.  Biological agents

Biogenic particles or viable particles which are contaminants of biological origin consist of bacteria, molds, fungus, viruses, pollen etc. The sources of these biological agents are animals and human as carriers of those agents, soil and plant debris, saliva and dander of pets. The health effects associated with biological agents are influenza (including avian flu), severe acute respiratory syndrome (SARS), measles,tuberculosis and chicken pox as well as allergic reactions such as hypersensitivity pneumonitis, allergic rhinitis and certain types of asthma. House dust contaminated with fecal pellets of dust mites is also one of the strongest allergic materials found indoors. The biological agents are located at wet or moist places such as bathrooms, flooded basements, furniture and poorly maintained humidifiers and air conditioners. An example of bacterium linked to central air systems is Legionella pnemonophila causing a respiratory illness, Legionellosis.

4. Indoor air pollution in vehicles

The pollutants are generated or trapped inside the vehicle. The pollutants monitored in an air conditioned car were VOCs (toluene, benzene, ethyl benzene, xylene), NOx and SOx. Exposure to high levels of toxic air pollutants while commuting in closed vehicles are problem of concern.

5. Greenhouse gases

The flow of incoming and outgoing energy from the sun to the earth is Earth’s energy budget. About 29 percent of the solar energy that arrives at the top of the atmosphere is reflected back to space by clouds, atmospheric particles, or bright ground surfaces like sea ice and snow. This energy plays no role in Earth’s climate system. About 23 percent of incoming solar energy is absorbed in the atmosphere by water vapor, dust, and ozone, and 48 percent passes through the atmosphere and is absorbed by the surface. Thus, about 71 percent of the total incoming solar energy is absorbed by the Earth system. The Earth naturally absorbs and reflects incoming solar radiation and emits longer wavelength terrestrial (infra red) radiation back into space. On average, the absorbed solar radiation is balanced by the outgoing terrestrial radiation emitted to space. The rest of the heat, also known as infrared radiation, is trapped in the atmosphere by clouds and greenhouse gases, such as water vapor and carbon dioxide. The energy from this absorbed terrestrial radiation warms the Earth’s surface and atmosphere, creating what is known as the “natural greenhouse effect”. Without the natural heat-trapping properties of these atmospheric gases, the average surface temperature of the Earth would be about 33oC lower (IPCC 2001). In short 15oC  –  33oC  = -18oC(Earth’s surface temperature) (Green house effect (33oC)  (Temperature without GHE)

The term greenhouse effect was proposed by Joseph Fourier in 1824 and was quantitatively explained by a Swedish Chemist Svante Arrhenius in 1896. The percent contribution of natural green house gases to GHE is given in Fig 1.

Fig. 2 Percent global contribution of GHG emissions by anthropogenic activities (IPCC,2014)

According to the Third Assessment Report (TAR) of the Intergovernmental Panel on Climate Change, the increase in concentration of CO2 is by 29 per cent, CH4 by 150 per cent and N2O by 15 per cent in the last 100 years. The emissions of greenhouse gases is mainly from electricity and heat production, agriculture, industry, transportation and buildings and the contributions are as per Fig 3.

6.2 Methane

Anthropogenic activities like fossil fuel production, enteric fermentation in livestock namely cattle, buffalo, sheep, goats, poultry, donkeys, camels, horses, manure management, cultivation of rice, biomass burning, and waste management releases methane to the atmosphere to a significant extent. Natural sources of methane include wetlands, permafrost, oceans, freshwater bodies, non-wetland soils, and other sources such as wildfires. The natural and human induced sources and sinks of CH4 are given in Table 2.

Table 2:Global sources and sinks of atmospheric methane

Source/Sinks	Methane emission range (Tg/year)
Natural
Wetlands
55-150
Termites	10-50
Oceans, freshwater	5-50
Other	10-40
Anthropogenic
Fossil fuel
70-120
Cattle	65-100
Rice paddy	20-100
Other sources
Biomass burning	20-80
Landfills	20-70
Animal waste	20-30
Domestic sewage	15-80
Total identified sources	410-660
Total sinks	430-600
Atmospheric increase	35-40

Source: IPCC report, Jain et al in TERI, 2015

6.3 Nitrous oxide

Agricultural soil management, animal manure management, sewage treatment, mobile and stationary combustion of fossil fuel and nitric acid production are the major anthropogenic sources. Nitrous oxide is also produced naturally from a wide variety of biological sources in soil and water, particularly from microbial action from the measurements for N2O (Table 3).

Table 3: Sources and sinks of nitrous oxide

6.4 Fluorinated gases (F-gases) – Fluorinated gases include hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6), CFCs, and halons. The synthetic gases have not existed in the atmosphere before the 20th century. Industrial processes, refrigeration, and the use of a variety of consumer products contribute to emissions of F-gases,

Global warming potential of GHGs is an index defined as the cumulative radiative forcing between the present and some chosen later time horizon caused by a unit mass of gas emitted now. It is used to compare the effectiveness of each GHG to trap heat in atmosphere relative to a standard gas, CO2 and commonly adopted standard of 100 year for reporting GHGs. The GWP values of CH4 and N2O emissions as 21 and 310 respectively.

7. Impacts of air pollution and greenhouse gases

The air pollution causes impact on environment and health. The environmental impacts are Increase in temperature

The IPCC report, the global mean temperature reported at the end of 20th century was higher by 0.40 – 0.76oC than that at the end of 19th century (IPCC, 2007) and the two-thirds of the increase occurred in the last three decades. The IPCC has projected a rise of 1.1 to 6.4 oC in temperature by the end of twenty first century. The rise in temperature will be more evident in high latitudes in the northern hemisphere. In India it will go up to 1oC in summer and 3.4oC in winter. The average annual temperatures are expected to increase. The rising temperatures will also thaw permafrost in the Arctic. Heat waves are likely to increase in frequency and severity, resulting in higher risks of forest fires.

Change in rainfall pattern

The precipitation has become spatially variable and the intensity and frequency of extreme events has increased. The increase in precipitation is expected to be combined with more frequent heavy precipitation events, resulting in higher risks of flooding.

Sea level rise Snow, sea ice and glacier coverage will decrease due to higher temperatures, resulting in rising sea levels and increased coastal flooding. The sea level also has risen at an average annual rate of 1–2 mm during this period.

• Climate change
• Reduction in crop yield
• Increase in pests and diseases
• Many wildlife species will have difficulty adapting to a warmer climate and will likely be subject to greater stress from diseases and invasive species.
• Effect human and animal health The 16% of lung cancer deaths, 11% of chronic obstructive pulmonary disease deaths, and more than 20% of is chaemic heart disease and stroke are associated with ambient fine particulate matter.

8. Categories of Air Quality

The air quality has been categorized into four broad categories based on an Exceedence Factor (the ratio of annual mean concentration of a pollutant with that of a respective standard). The Exceedence Factor (EF) is calculated as follows:

The four air quality categories are:

• ü Low pollution (L): when the EF is < 0.5
• ü Moderate pollution (M) : when the EF between 0.5 – <1.0
• ü High pollution (H) : when the EF is between 1.0 – <1.5;
• ü Critical pollution (C) : when EF is > 1.5

The pollution level in industrial, residential, rural& others areas and ecologically sensitive area were classified based on annual mean concentration range of SO2,NO2, PM10.

9. Air quality monitoring and air quality standards

Air quality monitoring is the primary activity for improvement in air quality and public awareness about air pollution. In India, ~350 air quality monitoring stations are operated by the Central Pollution Control Board (CPCB) and the State Pollution Control Boards. The Government has taken several measures to mitigate air pollution which include:

9.1. National Ambient Air Quality Standards (NAQS)

The Clean Air Act amended in 1990 identified two types of National Ambient Air Quality Standards. Primary standards provide public health protection, including protecting the health of “sensitive” populations such as asthmatics, children, and the elderly. Secondary standards provide public welfare protection, including protection against decreased visibility and damage to animals, crops, vegetation, and buildings. The Central Pollution Control Board notified the National Ambient Air Quality Standards with immediate effect on 18th November, 2009 for 12 pollutants – PM10, PM2.5, NO2, SO2, CO, O3, NH3, Pb, Ni, As, Benzo(a)pyrene, and Benzene.

9.2. National Air Quality Index (AQI)

The Ministry of Environment, Forests and Climate Change announce the National Air Quality Index on October 2014 introduced by prime Minister on 6th April, 2015. AQI is defined as an overall scheme that transforms weighted values of individual air pollution related parameters (e.g. SO2, CO, visibility, etc.) into a single number or set of numbers is widely used for air quality communication and decision making. An AQI system is devised in India from air quality monitoring procedures and protocols, Indian National Air Quality Standards (INAQS), and dose-response relationships of pollutants with objective to quickly disseminate air quality information (almost in real-time) that entails the system to account for pollutants which have short-term impacts. AQI is usually based on criteria pollutants (i.e. PM10, PM2.5, SO2, NO2, CO and O3) and NH3, and Pb.

The selection of parameters primarily depends on AQI objective(s), data availability, averaging period, monitoring frequency, and measurement methods. The PM10, PM2.5, NO2, SO2, NH3, and Pb standards are 24-hourly as well as annual average standards, Ni, As, benzo(a)pyrene, and benzene have only annual standards and CO and O3 have short-term standards (01 and 08 hourly average). The proposed index has six categories as given in Table 2.

Table 2: Categories of AQI

The AQI is helpful for general public to know air quality in a simplified way, a politician to invoke quick actions, a decision maker to know the trend of events and to chalk out corrective pollution control strategies, a government official to study the impact of regulatory actions and a scientist who engages in scientific research using air quality data.

10.  Measures to improve air quality

10.1.  Adoption of emission norms and fuel regulation standards

The amount of air pollutants released by the internal combustion engine equipments is managed by using cleaner fuel with low sulphur content and improved combustion engines. India is following the Bharat Stage fuel norms and as of 26th November 2011, BS – IV norms are applicable in 63 selected cities whereas BS –III norms are applicable in the rest of the country. The plan is to impose Bharat V fuel and emission norms by 2018 and Bharat VI by 2021.

Low sulfur fuels are critical to lowering direct emissions of particulate matter (PM) from on-road traffic, i.e.ultra-fine soot particles (of great concern due to their health impacts and are a leading cause of lung cancer) and black carbon (an important climate pollutant).

10.2. National urban transport policy

The percent of personal transport such as cars and two-wheelers in most of the Indian cities accounts for 45- 48% share in the modes of transport used. The National Urban Transport Policy was launched in 2006 by the Ministry of Urban Development (MoUD) for encouraging greater use of public transport in urban areas. It was reviewed in 2014 seeks to prioritize the use of public transport running on cleaner fuel and technology and develop a people-centric sustainable multi-modal urban transport network, taking into consideration the unique characteristics and specific situations prevalent in cities. It promote public transport network including Metro.

10.3.  Reducing the dependence on biomass burning in rural households

The Government of India has focused on the importance of clean and efficient cook stoves in order to reduceemissions as well as the health hazards associated with inhalation of harmful emissions from burning of biomass that contribute to indoor air pollution in rural areas and urban areas. The National Biomass Cook stoves Programme (NBCP) was launched by the Ministry of New and Renewable Energy topromote the use of improved cookstoves, which would result in reduced emissions and offer cleaner cooking energysolutions. Unnat Chulha Abhiyan has been launched to expand the deployment of the improved cook-stoves across the country.

10.4. Switching to renewable energy

The introduction of cleaner or alternate fuel like CNG, LPG etc. helps in reducing the exhaust gas emissions from the vehicles. In 1995 the Supreme Court ordered the closure and relocation of  polluting industries in Delhi. In 2001 the Court ordered the closure of all polluting and non-polluting industries that were located in residential areas but did not conform to the Delhi Master Plan. And, in 2002 it ordered the preparation of a scheme for compulsory switch over to CNG/LPG as automotive fuel for all public transport vehicles. The shift from consumption of fossil fuel to renewable energy sources like solar, wind, hydro, tidal, geothermal, biomass energy also enable reduction of negative impacts on air.

India is extremely rich in renewable energy (RE) sources, such as wind, solar and small hydro, however, green energyaccounts for only 12.14%of India’s total installed power capacity. The Jawaharlal Nehru National Solar Mission (JNNSM), part of the missions launched as part of the National Action Plan on Climate Change seeks to tap the immense potential of solar power as a future energy source in the country

The enhancement of energy efficiency, promotion of use of renewable energy resources and introduction of environmental measures such as enhancement of afforested land area, efficient low energy intense agricultural practices, waste management will also reduce the emission of air pollutants. The adaptation of Kyoto Protocol in the year 1997 necessitated developed economies to reduce their collective emissions of six important greenhouse gases by at least 5.2% as compared to 1990 level during the period 2008–2012. The principal mechanisms available to India for financing climate change mitigation activities and technology transfer under the UNFCCC are the CDM and the GEF.

Summary

• Urban air quality is greatly affected by transportation and industrial sector.
• The indoor air quality depends on combustible, noncombustible pollutants, hazardous chemicals and biological agents
• National Ambient Air Quality Standards, Air Quality Index and other measures have taken by Government to mitigate air pollution
• Carbondioxide, methane, nitrous oxides, F-gases are the major GHGs generated by human induced activities from industries, transportation, agriculture, waste sectors.
• The emission of green house gases effect temperature, rainfall, sea level rise, crop yield, human and animal health and increase pest and diseases.
• Adoption of emission norms and fuel regulation standards, National Urban Transport Policy,reducing the dependence on biomass burning in rural households, switching to renewable energy, efficient low energy agricultural practices, proper waste management improves the air quality and also helps in mitigation measures for reduction of greenhouse gases.