Clearing the Air: A Brief Guide to Understanding Air Pollution

What is Air pollution?

Air pollution is the presence of harmful substances in the atmosphere that can damage the health of humans and other living beings, or cause harm to the climate and materials. It can be caused by different agents that change the natural characteristics of the air. Airborne pollutants are dangerous to human health, animals, and plants, and can also cause damage to structures.

What are the causes of air pollution? 

Air pollution is caused by the incomplete burning of fossil fuels like coal, oil, and gasoline. The main sources in the US are coal power plants, industries, and vehicles, while nature contributes by releasing hazardous substances such as wildfire smoke and volcanic ash. Air pollution happens when harmful gases and chemicals, including particulate matter that can cause respiratory and cardiovascular problems, are released. Human activities like driving vehicles, using fossil fuels, and practicing agriculture cause air pollution.

What are the types of air pollution? 

Air pollution has various forms such as particulate matter, carbon dioxide, carbon monoxide, ozone, nitrogen dioxide, sulfur dioxide, and volatile organic compounds (VOCs). Primary pollutants are directly emitted into the air while secondary pollutants form when primary pollutants interact with other substances in the atmosphere. Sources of air pollution include burning fossil fuels, domestic wood heaters, prescribed burns and bushfires, mining, other land uses, road dust, and sea salt.

What are the effects of air pollution?

Air pollution harms human health by causing heart disease, lung cancer, and respiratory diseases like emphysema and can also cause stroke, chronic obstructive pulmonary disease, and other serious medical conditions. The environment is also affected as it reduces visibility and sunlight causing acid rain.

What are the control measures for air pollution?

Using public transportation, biking, or walking instead of driving can reduce air pollution. Turning off lights when not in use, recycling and reusing items, avoiding plastic bags, and reducing forest fires are also ways to control air pollution. Minimizing fire use and reducing industrial emissions can help as well. Using electric or hand-powered lawn equipment instead of gas-powered engines is another way to reduce air pollution. Additionally, reducing energy consumption, promoting energy efficiency and using renewable energy sources, and improving industrial processes’ efficiency are other measures that can be taken.

These above are some basic Q&A of Air Pollution

Some of the data collected from the WHO Publication are mentioned below:

COMEAP statement: response to the publication of the World Health Organization Air quality guidelines 2021

The WHO has released revised guidelines for air quality that include lower values for particulate matter and nitrogen dioxide. These guidelines are based on epidemiological evidence and represent long-term concentrations where adverse health effects have been observed. Short-term guidelines are derived from long-term ones and are based on daily observations at the 99th percentile of distributions. In cases where there is insufficient data, good practice statements were produced. The UK Committee on the Medical Effects of Air Pollutants (COMEAP) welcomes these revised guidelines and emphasizes that even low levels of pollutants can harm public health.

World Health Organization (WHO) air quality guidelines (AQGs) and estimated reference levels (RLs) (a)

Pollutant	Averaging period	AQG	RL	Comments
PM10	1 day        Calendar year	45μg/m3        15μg/m3		99th percentile (3-4 exceedance days per year). Updated 2021 guideline     Updated 2021 guideline
PM2.5	1 day        Calendar year	15μg/m3        5μg/m3		99th percentile (3-4 exceedance days per year). Updated 2021 guideline     Updated 2021 guideline
O3	Maximum daily 8-hour mean       Peak season (b)	100μg/m3        60μg/m3		99th percentile (3-4 exceedance days per year). New 2021 guideline     New 2021 guideline
NO2	1 hour  1 day         Calendar year	200μg/m3  25μg/m3          10μg/m3		99th percentile (3-4 exceedance days per year). New 2021 guideline     Updated 2021 guideline
BaP	Calendar year		0.12ng/m3
SO2	10 minutes     1 day	500μg/m3     40μg/m3		99th percentile (3-4 exceedance days per year). New 2021 guideline
CO	1 hour     Maximum daily 8-hour mean     1 day	30mg/m3     10mg/m3        4mg/m3		99th percentile (3-4 exceedance days per year). New 2021 guideline
C6H6	Calendar year		1.7μg/m3
Pb	Calendar year	0.5μg/m3
As	Calendar year		6.6ng/m3
Cd	Calendar year	5ng/m3 (c)
Ni	Calendar year		25ng/m3

 

(a) As WHO has not set an AQG for BaP, C6H6, As and Ni, the RL was estimated assuming an acceptable risk of additional lifetime cancer risk of approximately 1 in 100 000. 

(b) Average of daily maximum 8-hour mean concentration in the six consecutive months with the highest six-month running average O3 concentration. 

(c) AQG set to prevent any further increase of Cd in agricultural soil, likely to increase the dietary intake of future generations.

 

Causes and their Harm:

 

PM10 and PM2.5 

PM10 and PM2.5 are two types of particulate matter in air pollution, with diameters of 10 micrometers or less and 2.5 micrometers or less, respectively. They come from various sources, such as vehicle exhaust, power plants, and wildfires. PM2.5 particles pose a higher risk because they can enter the deep parts of your lungs and bloodstream causing respiratory symptoms and exacerbating pre-existing diseases. Long-term exposure is linked to disease progression, while short-term exposure worsens pre-existing conditions. Everyone is at risk of exposure, but those who spend more time outdoors or live in highly polluted areas are at greater risk.

 

Ozone O3 

Ozone is an air pollutant caused by chemical reactions between pollutants from vehicles, factories, and fossil fuels. It harms crops, reducing growth and causing disease. While Arizona’s ozone levels have decreased over time, long-term exposure to ozone increases the risk of metabolic disorders. Ground-level ozone is harmful to both people and plants.

 

Nitrogen dioxide NO2 

NO2 is a dangerous air pollutant that comes from sources like cars, power plants, and industry. It harms the human lungs and can make people more likely to get respiratory infections. NO2 also hurts plants, especially when mixed with sulfur dioxide and ozone. Breathing in NO2 can cause coughing, and wheezing, and make asthma worse.

 

Benzo[a]pyrene BaP

BaP is a chemical compound that comes from burning coal, oil, gas, and tobacco. It is part of a group called PAHs found in air pollution. BaP causes cancer in humans and increases the risk of lung, bladder, and skin cancer even at low levels. It also harms the respiratory and immune systems causing inflammation, asthma, infections, and diseases. Burning fossil fuels for power production, transportation, or making chemicals are the main source of BaP in air pollution. Additionally, tobacco smoke is a significant source of exposure for smokers and non-smokers. Although it remains in polluted urban atmospheres during summer for just a few hours due to chemical reactions and photolysis its effects on health are serious.

 

Sulfur Dioxide SO2 

SO2 is a gas pollutant created when sulfur-based fuels like coal, oil, and natural gas are burned. It can cause acid rain that harms delicate ecosystems. Inhaling SO2 may irritate the respiratory tract and increase the risk of infections, causing coughing, mucus production, asthma symptoms, and other respiratory problems. Individuals situated near volcanic SO2 emissions may also face hazardous levels of pollution.

 

Carbon Monoxide CO 

Carbon monoxide (CO) is a harmful gas that can’t be seen or smelled. The incomplete burning of fuels like gasoline, oil, and coal releases CO into the air. CO reduces oxygen delivery to body organs and tissues, causing harmful health effects. Exposure to lower levels of CO is most serious for those with heart or lung disease, infants, and young children. Pollutants of greatest public health concern include PM, CO, O3, and NO2. When CO is released into the atmosphere it affects greenhouse gases which are linked to climate change and global warming.

 

Benzene C6H6 

Benzene, or C6H6, is a dangerous pollutant present in both indoor and outdoor air. Products like glues, paints, furniture wax, and detergents contain benzene. Being exposed to benzene for long periods through inhaling it could lead to blood disorders such as reduced red blood cells and aplastic anemia, particularly in workplaces. It’s important to monitor the presence of harmful air pollutants like benzene for better air quality. If a product has caused environmental pollution or air pollution, informing relevant authorities is necessary.

 

Lead Pb 

Lead (Pb) is a heavy metal present in the air due to natural and human activities. It can be harmful, particularly to young children, as it can cause damage to the central nervous system, kidneys, and immune system. The main sources of lead in the air are lead smelters, iron and steel foundries, and waste incinerators. The EPA has successfully reduced national levels of lead in the air by 86% from 2010 to 2020 through regulatory measures.

 

Arsenic As 

Arsenic, a toxic pollutant, is present in the environment and can cause cancer, skin lesions, and various diseases when ingested or inhaled long-term from water, food, or air pollution. Natural sources like volcanic eruptions and human activities such as the burning of fossil fuels, mining activities, and the use of arsenic-containing pesticides contribute to arsenic in the air. Although exposure levels that cause minor effects are unclear, it’s established that long-term exposure can result in serious health implications including cardiovascular diseases and skin lesions.

 

Cadmium Cd 

Cadmium is found in the air due to natural and human-made causes. The primary sources of airborne cadmium are smelting, burning coal or oil, and incineration. Inhaling cadmium from air pollution can harm humans by causing kidney and liver issues, lung swelling, and reproductive damage. Cadmium mainly harms kidneys when inhaled as fumes or vapors but can also affect other organs and systems in the body.

 

Nickel Ni 

Nickel, a frequent contaminant in the air, can cause adverse health effects like breathing difficulties, skin irritation, and cancer. Common sources of nickel include industrial emissions, usage of fuel (liquid or solid), and municipal and industrial waste. Household air pollution stems from inefficient fuels and technologies used within the home that release pollutants such as nickel into the air. These harmful pollutants include nitrogen oxide and sulfur dioxide along with small particles called Particulate Matter that can affect our respiratory system.

 

Worlds Pollution Rate 2023:

 

Air pollution is a serious issue across the globe, and it is worrying to know that some countries are more affected than others. According to IQAir, Mongolia, Myanmar, and Lebanon are currently the most polluted countries in the world. However, when considering the pollution rate chart by country, Bangladesh, Chad, and Pakistan top the list as having the highest pollution index. 

To get a better understanding of how air pollution affects people worldwide, an interactive map has been created that shows the death rates from air pollution across different regions of the world. This measure is expressed as the number of deaths per 100,000 people. The data on this map highlights just how alarming air pollution can be, with many countries experiencing far too many deaths due to poor air quality. 

It’s clear that urgent action is needed to address air pollution and improve air quality around the world. Governments need to step up their efforts to reduce emissions from factories and vehicles while also promoting cleaner energy sources such as wind and solar power. Individuals can also play their part by making small changes in their daily lives like walking or cycling instead of driving or reducing their consumption of meat and dairy products which have a high carbon footprint. 

Addressing this global challenge requires collective action from all sectors of society - governments, businesses, and individuals alike. We must act now before it’s too late for future generations.

 Air Pollution in India :

Some Q&A on the effects of Air pollution;

 

What are the major impacts of climate change and air pollution on human health in Indian cities?

The major impacts of climate change and air pollution on human health in Indian cities. The expanding urban areas with extreme climate events (high rainfall, extreme temperature, floods, and droughts) are posing human health risks. The intensified heat waves as a result of climate change have led to the elevation in temperature levels causing thermal discomfort and several health issues to urban residents. The study also covers the increasing air pollution levels above the prescribed standards for most of the Indian megacities. The aerosols and PM concentrations have been explored, and the hazardous health impacts of particles that are inhaled by humans and enter the respiratory system have also been discussed. Therefore, the major impacts of climate change and air pollution on human health in Indian cities include thermal discomfort, respiratory issues, and other health risks.

 

How do extreme climate events such as floods, droughts, and heat waves affect urban residents' health in India?

Extreme climate events such as floods, droughts, and heat waves affect urban residents' health in India in several ways. The expanding urban areas with extreme climate events are posing human health risks. The intensified heat waves as a result of climate change have led to the elevation in temperature levels causing thermal discomfort and several health issues to urban residents. Urban drought and floods caused by changing climate due to scarcity or excess rainfall indirectly affect human health. Drowning, hypothermia, and trauma are some physical effects of floods on human health. Therefore, extreme climate events such as floods, droughts, and heat waves can cause physical and mental health issues for urban residents in India.

 

What are the hazardous health impacts of aerosols and PM concentrations that exceed prescribed standards in most Indian megacities?

The hazardous health impacts of aerosols and PM concentrations exceed prescribed standards in most Indian megacities. The aerosols and PM concentrations have been explored, and the hazardous health impacts of particles that are inhaled by humans and enter the respiratory system have also been discussed. The hazardous health impacts of aerosols and PM concentrations include respiratory issues, cardiovascular diseases, and other health risks. Therefore, it is important to monitor air pollution levels regularly and take necessary measures to address climate change and air pollution in Indian cities.

 

How did COVID-2019 lockdown impact air quality levels in Indian cities, and what were its associated health effects?

During the COVID-2019 lockdown in Indian cities, there was a reduction in the concentration of air pollutants. The improvement in air quality during the COVID-19 lockdown was reported by Karuppasamy et al., revealing improved mortality rates with fewer deaths in India and worldwide due to air pollution. The reduction in levels of various air pollutants in more Indian cities during the COVID-19 lockdown period has been presented in Table 2 of the paper. The study revealed more than 50% reduction in PM10 and PM2.5 concentrations. About 40-50% improvement in air quality was observed using the data collected from 34 monitoring stations. The reduction in air pollutant concentration during the COVID-19 lockdown is associated with several health benefits. Saxena et al. reported that the reduction in respirable particulates during the COVID-19 lockdown in India led to health benefits such as a decrease in respiratory and cardiovascular diseases. Therefore, the COVID-19 lockdown had a positive impact on air quality levels in Indian cities, leading to several health benefits.

 

Can you explain how air pollutants like aerosols directly or indirectly affect Earth's climate by altering cloud properties and radiation transfer processes?

Air pollutants like aerosols can affect Earth's climate both directly and indirectly. Directly, aerosols can absorb and scatter solar radiation, leading to surface cooling and atmospheric heating. Indirectly, aerosols can alter the properties of clouds, affecting the radiation transfer processes. This can influence the radiation equilibrium of Earth via radiative forcing and chemical perturbations. The concentration of atmospheric pollutants emitted by human activities can also influence the atmospheric structure and climate. These small-sized particles can weaken the urban heat island effect by up to 1 K under heavily polluted conditions. Therefore, air pollutants like aerosols can have a considerable impact on Earth's climate by modifying the heat wave frequency, the intensity of storms, and precipitation patterns.

 

 “Breathe in nature, not pollution”