Wildfires are an unplanned phenomenon that destroys a natural area such as forest, grasslands or prairie. They are often caused by human interventions or natural manifestations like lightning, volcanic eruptions etc. The risk of wildfires increases in extremely dry conditions, drought and during high winds. 80 -90% of wildfire smoke, by mass, is within the fine particle size class of 2.5 micrometres in diameter or smaller. The size and frequency of wildfires are growing due to climate change and vice-versa. It is estimated that 6.2 million people were affected from wildfires between 1998– 2017.
As we all know that living plant matter purifies the atmospheric air that we breathe. They achieve this by taking in carbon dioxide, greenhouse gases and air impurities and sending out oxygen thereby purifying the atmosphere.When plant life is exterminated by wildfires the quality of air that we breathe deteriorates. Expulsion of huge amounts of smoke and dust and emission of greenhouse gases thus leads to weather fluctuations and global warming.
Air pollution due to wildfires can spread over thousands of kilometres with airborne particles and gaseous pollutants suspended in the air for long periods of time. Wildfire smoke is composed primarily of carbon dioxide and water vapour. Other common smoke components present in lower concentrations are carbon monoxide, formaldehyde, acrolein, polyaromatic hydrocarbons, and benzene. Despite carbon dioxide’s high concentration in smoke, it poses a low health risk due to its low toxicity. Rather, carbon monoxide and fine particulate matter, particularly 2.5 µm in diameter and smaller, have been identified as the major health threats. Other chemicals are considered to be significant hazards but are found in concentrations that are too low to cause detectable health effects. Small particulates suspended in the air which comes in solid form or in liquid droplets are also present in smoke.
I’ll Effects of wildfire smoke on mankind and habitat
Direct emissions of toxic pollutants can affect first responders and local residents. In addition, the formation of the other pollutants as the air is transported can lead to harmful exposures for populations in regions far away from the wildfires. The fine particulate matter contained in wildfire residues can cause cardiovascular and respiratory problems, asthma exacerbations, increased rate of heart attacks, eye and nose allergy and increased rate of mortality related to cardiovascular and respiratory diseases. It is estimated that landscape fires globally cause 3,39,000 premature deaths in a year. The degree of wildfire smoke exposure to an individual is dependent on the length, severity, duration, and proximity of the fire. People are exposed directly to smoke via the respiratory tract through inhalation of air pollutants. In general, the elderly, pregnant women, children, heart and asthma patients we’re found to experience adverse health issues from wildfire smoke exposure
Wildfires also emit substantial amounts of volatile and semi-volatile organic materials and nitrogen oxides that form ozone and organic particulate matter, these increased fire byproducts in the troposphere can increase ozone concentration beyond safe levels.
For example, the forest fires in Indonesia in 1997 were estimated to have released between 0.81 and 2.57 gigatons of CO2 into the atmosphere, which is between 13%–40% of the annual global carbon dioxide emissions from burning fossil fuels. In June and July of 2019, fires in the Arctic emitted more than 140 megatons of carbon dioxide, according to an analysis by CAMS. To put that into perspective this amounts to the same amount of carbon emitted by 36 million cars in a year.
Atmospheric models suggest that these concentrations of sooty particles could increase absorption of incoming solar radiation during winter months by as much as 15%. The Amazon is estimated to hold around 90 billion tons of carbon. As of 2019, earth’s atmosphere has 415 parts per million of carbon, and the destruction of the Amazon would add about 38 parts per million.
Wildfires release large amounts of carbon dioxide, black carbon, brown carbon, and ozone precursors into the atmosphere. These emissions affect radiation, clouds, and climate on regional and even global scales.
Health precautions to reduce the effect of wildfire pollutants
When outdoor air is polluted by emissions from wildfires the following precautions are to be taken:
1) spend more time indoors;
2) keep windows and doors closed,
3) operate indoor particle filtration systems.
When sheltering indoors with windows and doors closed, it is important to reduce other indoor sources of particulate matter such as smoking, cooking, burning candles or incense, and unvented combustion equipment. Also, it may be uncomfortable and pose health risks to remain indoors with doors and windows closed in homes without air conditioning, as wildfires often occur during hot summer and fall weather, and it may be necessary to seek protection via other means.
The particle filtration systems could be installed in forced-air heating and cooling systems, with fans, run continuously when there is pollution from wildfires. Alternately, portable fan-filter systems (particle air cleaners) could be operated during wildfires. A side advantage is that routine use of either of these particle filter systems would also be expected to yield health benefits from reduced exposures to everyday sources of particles