Indoor air Quality: A safety measure of airborne diseases in rural area

Indoor air pollution. Credit: Swapnaja K Jadhav

Amid ongoing COVID-19 pandemic, while trying to understand about this new SARS corona virus, scientists have found out correlation between prolonged exposure to air pollution and lethality of SARS Corona virus patients (Xiao et al. 2020 and Conticini et al. 2020). This is might be one of the reasons for higher fatality due to corona virus in the most polluted cities of the world. Since most of the viral infections are through aerosol transmission, air pollution plays major role as viral aerosol interacts with airborne fine particles and enhances their infectivity (Groulx et al. 2018 and Tellier et al. 2019). Villages have relatively low outdoor air pollution; however, the danger stays inside the home with 5-10 times more severity in the form of indoor pollution created by use of low quality fuels and inefficient stoves. The harmful compounds present in the polluted air are responsible for several chronic health conditions related to respiratory and cardio vascular system. A Person with such conditions becomes highly vulnerable to severe or fatal disease if get infected with COVID-19. If not ignored these facts and findings, precaution can be taken to avoid indoor pollution as it may become co-factor to create hazardous scenario for rural regions in upcoming days of this, as it is currently facing mass migration from cities.

Worldwide more than 2.9 billion people are still using wood, dung cakes, coal, forest residue, crop residue and kerosene based cooking appliances. In rural area of  India, despite of  94% of LPG connection under PM Ujwala Yojna, 50 million of households still use solid fuels and kerosene based stoves for cooking (Arlington et al. 2019) due to economical and temperamental issues. Most of these stoves do not meet the prescribed standards. Such inefficient stoves pollute the kitchen and home environment due to incomplete combustion that adversely affects health of people having prolonged exposure.  Traditional stoves using solid fuels emits carbon monoxide (CO), fine particulate matter (PM 2.5), carbon dioxide (CO2),  black carbon, nitrogen dioxide (NO2), NOX, SOX, volatile organic compounds (VOCs), ozone (o3), etc and also produce secondary organic aerosols. Houses having such appliances generally have Fine particulate matter (PM 2.5, 24 h) concentrations in the range of 163 µg m3 to 609 µg m3 (Balakrishnan et al. 2013).

Different pollution components are responsible for different diseases. Worldwide yearly 3 million deaths are attributed to indoor pollution (WHO, 2018). Prolonged exposure to fine particles (PM2.5) are matter of more concern here as they are so tiny and remain suspended in air and while inhaled can reach up to alveoli of lungs where air comes in contact with blood and deposit on small air tracks. This damages the lungs protective lining tissues called cilia (Cao et al., 2016) and results in to allergen creating higher risk of chronic inflammation stimulus even in young and healthy person and become responsible for reduced heart function and related diseases. Exposure to fine particulate matter also increases risk of rheumatic disease in children, myocardial infarction and congestive heart failure. Sulfur dioxide (SO2) has a prominent role in respiratory system inflammation, NO2 and ozone (O3) levels are associated with inflammation, immune and oxidative stress response (Schraufnagel et al. 2019). Most affected groups by indoor pollution are women; elderly people and young children as they spend 85% of their time at home. If person having such health condition gets infected with any other severe respiratory disease causing agent, it may worsen the response of body. The data reported on 3rd May 2020 about corona virus cases in New York City reported that 75.81% deaths of Covid-19 patients were with pre-existing conditions like diabetes, cancer, immunodeficiency, heart disease, hypertension, asthma, and kidney and liver diseases (NYC Health, 2020) is also support that people with these underlying conditions are more vulnerable to COVID-19 (Barnett, B. 2020).

Outdoor air pollution occur due to number of reasons making it difficult to control like industries chimney exhaust, crop residue burning, dusty storms, low quality fuel use in vehicles, low maintained engines, while indoor pollution is much controllable as mainly cooking and lighting process are involved. Many organizations are promoting use of improved cook stoves for solid fuels and smokeless fuels. In India Improved cook stoves were widely disseminated through NPIC (National Program on Better Cook stove, 1985), however had limited success. The Ministry of New Renewable Energy, Government of India has also taken steps for promotion of biomass-based improved cook stoves through standardization of designs, quality assurance and quality control of the stoves which is showing success in recent years. Improved cook stoves with higher thermal efficiency, higher heat transfer, lower emissions, low particulate matter and safety features can successfully reduce emission by 90% and can save 40-50% of fuel. There are a variety of popular biomass based stoves in the market such as Oorja-Plus, Philips and TERI cook stoves in India, CIAE stove, IDBI Cook Stove, Vikram Stove, Domestic Gasifier Stove (DGS2), Commercial Gasifier Stove (CGS3) and TERI SPT 0610 Stove etc. The list of certified improved cook stoves is available on MNRE website.  The cost of the family size stove ranges from 13 to 40 $ (1,000 to 3,000 INR) and of community size stove is more than 265 $ (20,000 INR) depending on size. Four main strategies can be employed to improve domestic air quality: (1) Design and implementation of alternative cook stoves; (2) Improved domestic ventilation; (3) Use of more efficient fuel, and (4) Changes in cooking behaviour.

Pollution, outdoor or indoor need strict control on emission causing factors, because H1N1, Severe acute respiratory syndrome (SARS), middle-east respiratory syndrome (MERS)  and now SARS COVID-2 has shown that higher risk of airborne diseases is persisting since centuries and, new and unknown viruses which will be tolerant to changing climatic conditions (Casadevall, A., 2020  ) are more prone to dwell in the future. Indoor pollution has more probability to cofactor such transmission and fatality than outdoor pollution. However, figurative study should be carried out to determine the various pollutant levels and its effect in combination with airborne pathogens. Well ventilated houses, quality fuels, improved cook stoves and precaution taken during cooking can avoid indoor pollution, while comprehensive control on open air pollution factors can be a long term safety measures to reduce vulnerability to ongoing and future pandemic diseases related to respiratory and related systems. Early awareness about problems and their solutions, and incorporation can makes us prepared to fight against any crisis at minimum loss.


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