Airborne pollutants are pollutants that are capable of contaminating air, land, and water. These pollutants can come from various sources but they originate primarily from factories and automobiles. Air pollutants are any substance that is present in the air which has the potential to damage life, ecosystems or property. Besides the air pollutants that humans would release, there are natural sources of air pollution as well. Volcanoes and forest fires are some examples of natural sources of air pollution. Nevertheless, humans release more air pollutants compared to natural sources.
Air pollutants have a huge effect on the Earth’s waters especially the oceans. However, the relationship between air pollutants and the Earth’s waters is very complex. The process in which pollutants are deposited into the ocean is known as atmospheric deposition. Air pollutants with the highest potential to cause water quality degradation include nitrogen, mercury, combustion emissions, pesticides, and other heavy metals. All of the pollutants mentioned are capable of settling into bodies of water and damage the ecosystems present within them. Moreover, they pose a risk to public health. Mercury is the most hazardous air pollutant because of the way they behave in the environment. Air pollution is capable of causing short-term measurable damage to water quality. This occurs when hazardous chemicals would fall from the air as dust because of gravity or when the rain would wash the chemicals to the waterways which would eventually reach the oceans. Chemicals in the air may mix with the rain and fall down as acid rain.
Various gases in the atmosphere could also mix with each other and turn into poisonous substances. These gaseous mixtures could also turn into acid rain or snow. For instance, nitrogen oxides, carbon dioxide, and sulphur dioxide, which are gases that are emitted by burning fossils fuels, can mix together with rain creating acid rain. Vehicles are not the only things that burn fossil fuels, fossil fuel power stations, and base metal smelting plants burn fossil fuels as well. Airborne chemicals may fall to the ground and into the ocean due to gravity. Falling rain could also absorb carbon and sulphur dioxide as it is falling and turn into acid rain.
Acid rain is hazardous to the environment because it can damage both organic and inorganic matter. There have been cases where acid rain and/or acidic fog have significantly reduced trees’ foliage. Acid rain could also increase the amount of certain minerals that are present in the soil; aluminum is one of these minerals. To make matters worse, the acid rain could wash away the aluminum minerals and into water bodies like rivers, lakes, and ultimately into the oceans. The aluminum minerals can clog the gills of aquatic animals, compete with calcium in their bodies, and cause deformities in their young which could lessen their survival rate and would ultimately reduce their population.
Ocean water is normally slightly basic with an average pH of 7.8 to 8.1. However, researchers believe that the oceans have become slightly more acidic over the last century. Measuring this change is difficult because of the ocean’s large scale. Studies conducted on smaller water bodies revealed that as the water pH approaches 6.0 which is acidic, crustaceans, insects, and some plankton species may begin to disappear. If the water pH drops to 5.0, drastic changes in the plankton community would occur. This would allow less desirable species of mosses and plankton to dominate which may lead to reductions in fish populations. If this level of pH drop occurs in smaller lakes, the effect would be more drastic. The area with low pH would be devoid of fish, the bottom would be covered with undecayed material, and areas close to shore would be dominated by mosses. Acidification brought about by air pollution has a greater impact on land and in bodies of water that are smaller than the ocean.
The relationship between our oceans and the carbon dioxide that is released into the atmosphere is complex. Researchers from the Lawrence Livermore National Laboratory published an article which states that 80% of the carbon dioxide that is released into the atmosphere is absorbed by the oceans which would make them more acidic. This may not be ideal for the oceans but it is ideal for the atmosphere. When the oceans would absorb carbon dioxide, there would be fewer greenhouse gases in the atmosphere which aids in solving climate change. The oceans can act as a giant carbon sink. They have plankton, corals, algae and other photosynthetic bacteria which can convert the carbon dioxide that enters the ocean to oxygen through photosynthesis. Thus, it is unclear if this amount of carbon entering the oceans is a good thing or not.
Air Pollution Threatens Phytoplanktons
Phytoplanktons may have a huge positive impact on Climate Change. They are capable of reducing atmospheric carbon dioxide levels through photosynthesis.
Air pollution can cause eutrophication or the process of accumulation of nutrients in the water. When eutrophication occurs algal bloom may soon follow. Large numbers of algae including phytoplanktons may die off. The subsequent decay process of the algae could deplete the oxygen in the water ultimately creating dead zones aptly named because any organism that needs oxygen to survive would die in these zones.
Air pollution could also damage the ozone layer. Pollutants such as Chlorofluorocarbons or CFCs react with the ozone creating holes in the protective layer. CFCs are used for various purposes such as cleaning computer chips and air conditioning units or added in certain products as aerosol propellants. Holes in the ozone layer increase the amount of ultraviolet rays that reach the Earth’s surface. This ultraviolet light is capable of killing phytoplankton. Research conducted in Antarctica revealed that the ozone layer above the area is completely absent during spring. The same research also revealed a 6 to 12 percent reduction in the plankton population. The photosynthetic ability of phytoplanktons is negatively affected by ultraviolet light. In fact, an hour of exposure to ultraviolet light reduced the phytoplankton’s photosynthetic ability by up to 65%. This means that their ability to convert carbon dioxide to oxygen is severely reduced as well.
Acidification of water bodies can occur as a result of air pollution. A systematic review of studies that investigated the effects of water acidity on marine phytoplankton revealed that the optimum pH for marine phytoplankton is between 6.3 and 10. Some phytoplankton species can grow at a wider pH range. Usually around 0.5 to 1 pH above or below the established optimum pH range. The usual pH in typical coastal environments varies by 1 or more pH units. This goes to show that air pollution may cause fluctuations in the pH of water bodies which could then negatively affect the growth of marine phytoplankton. Eutrophication can amplify the rate at which the pH would fluctuate.
Mercury in the air may fall down into water bodies due to gravity. The presence of mercury in the water can negatively affect the physiological processes of phytoplanktons including photosynthesis.
Mercury in Water
There is naturally occurring mercury in the air, water, and ground. In the United States, the US Environmental Protection Agency set the maximum contaminant level to 2 µg/litre. Which means that if the level of mercury that is present in the area does not exceed this number, then the mercury level is most likely caused by the presence of naturally occurring mercury. The International Programme on Chemical Safety measured the amount of mercury in the air in 1990. According to their measurements, rainwater could contain 5 to 100 ng/litre of mercury. Mercury measurements in groundwater revealed that their average mercury concentration is 0.5 µg/litre. Volcanic activities may increase mercury levels naturally. A study conducted in Izu Oshima Island, Japan showed that frequent volcanic activity raised mercury concentrations of their wells by up to 5.5 µg/litre.
Depending on how mercury is introduced into the body, the percentage of mercury that would be subsequently absorbed would vary. If mercury is inhaled 80% of the mercury gets absorbed by the body. If the mercury is ingested through food only 7 to 8 percent of the total amount of mercury in that food is absorbed. If the mercury is ingested through water, only about 15% of the mercury present in that water is absorbed. Mercury is absorbed easily through the respiratory system compared to the digestive system.
Once the mercury is absorbed by the body they would rapidly accumulate in the kidney. The worst thing about mercury is that it may persist in the body for a long time. Mercury blood concentrations would drop by 50% after 1 to 3 days. The remaining mercury concentration would drop by another 50% after 1 to 3 weeks.
The primary negative health effects of mercury at high enough concentrations are neurological and renal disturbances. Liver damage is also a real possibility.
Terminal signs and symptoms, namely shock, cardiovascular collapse, acute renal failure and severe gastrointestinal damage, can appear as a result of ingesting an acute toxic dose of mercury. Acute oral poisoning leads to hemorrhagic gastritis and colitis. Acute oral poisoning may exhibit symptoms such as pharyngitis, dysphagia, abdominal pain, nausea and vomiting, bloody diarrhea and shock as well. Swelling of the salivary glands, stomatitis, loosening of the teeth, nephritis, anuria, and hepatitis may appear as late symptoms.
Acute mercury poisoning occurs when 500 milligrams of mercury chloride is ingested or if 0.05 to 0.35 mg/m3 of mercury vapour is inhaled. Exposure to 1 to 3 mg/m3 for only a few hours may lead to pulmonary irritation and destruction of the lung tissues. This could also damage the central nervous system leading to neurological disorders.
Improving Air Quality by Reducing Air Pollution
Among all types of pollution, air pollution is the single greatest environmental risk to human health. Air pollution is linked to numerous diseases and has been linked to approximately 6.5 million premature deaths. In developing countries, air pollution disproportionately affects the elderly, women, and children more. This is especially true in low-income populations for they are often exposed to high levels of ambient air pollution and indoor air pollution from things like wood fuel and kerosene.
Air pollution can be transported over long distances and across oceans and borders. Without aggressive intervention, it is estimated that the number of premature deaths caused by air pollution would increase by up to 50 percent by 2050.
Air pollution’s negative impacts on the economy, work productivity, healthcare costs and tourism bear a high cost. It may be difficult to accurately determine the returns that come from investing in air pollution control. However, most experts agree that investments in air pollution control would, at worst, break even. Cost-effective solutions to addressing air pollution do exist and should be taken advantage of.
All countries should take poor air quality into consideration when coming up with Sustainable Development Goals. This is especially true in the cities and urban areas of developing countries with air quality the does not meet the guidelines set by the World Health Organization.
Everyone has the power to reduce air pollution and improve air quality. Here are some of the things that you could do:
Reduce the frequency at which you use cars by carpooling, using public transport, using a bike, or walking whenever possible.
Keep the engines of your vehicles be it cars or boats properly tuned.
Improve fuel efficiency however you can such as keeping your tires properly inflated.
Avoid spills when refuelling by following gasoline refuelling instructions properly.
Always tighten your vehicle’s gas cap after refuelling.
Avoid spills when storing gasoline by using only “spill-proof” containers.
Try to conserve energy everywhere you go
When purchasing appliances or any equipment that uses electricity do your research beforehand and only purchase energy-efficient ones.
Always use paint, cleaning products, etc. that do not release any harmful fumes or air pollutants.
Mulch or compost leaves and yard waste.
Consider using gas logs instead of wood.
International Day of Clean Air for Blue Skies
The United Nations seeks to improve air quality in its member countries with the hopes of improving air quality globally. Their goal is to significantly reduce the number of deaths and illnesses that are brought about by air, water, and soil pollution and contamination by 2030.
The United Nations and its member countries recognize that clean air is essential for the health and day-to-day lives of people. Moreover, the international community acknowledges that methods for improving air quality lead to the mitigation of climate change as well.
Due to the willingness and keenness of the international community to improve air quality the United Nations General Assembly designated the 7th of September as the International Day of Clean Air for Blue Skies.
International Day for the Preservation of the Ozone Layer
The United Nations and its member states recognize the importance of our ozone layer and how certain air pollutants can damage this protective layer.
Several countries have agreed to phase out or reduce the usage of certain ozone-damaging substances such as chlorofluorocarbons or CFCs. This significantly improved the health of the ozone layer. With a healthy ozone layer, the Earth and its inhabitants, including phytoplanktons, are protected from harmful ultraviolet rays.
The International Day for the Preservation of the Ozone Layer started out as the Montreal Protocol. This is a global agreement that was meant to protect the ozone layer. This is one of the most successful environmental agreements because a lot of countries agreed to it and it was able to do its function. This agreement successfully healed the ozone layer. With the ozone layer gradually going back to normal, humans are protected from UV radiation, and economies and ecosystems are subsequently improved.
There are several chemicals that are extremely harmful to the ozone layer. These chemicals include halocarbons such as fluorine, chlorine, bromine or iodine. The halocarbons that contain bromine have a higher potential to damage the ozone layer compared to those halocarbons that contain chlorine. Methyl bromide, methyl chloroform, carbon tetrachloride and families of chemicals known as halons, chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) are the chemicals that introduced a lot of chlorine and bromine to the ozone layer causing damage to it.
Before the establishment of the Montreal Protocol other agreements have been made. The Vienna Convention for the Protection of the Ozone Layer was adopted and signed by 28 countries on March 22, 1985. The establishment of the Vienna Convention for the Protection of the Ozone Layer came about as a mechanism for cooperation to protect the ozone layer.
The primary objective of the Montreal Protocol is to use technological information and scientific knowledge to protect the ozone layer by controlling the total global production and consumption of substances that can damage it. The Montreal Protocol is built around several groups of ozone-depleting substances. This protocol lists groups of chemicals according to their chemical family. To meet its objective which is to eventually eliminate all of the ozone-damaging chemicals, the Montreal Protocol sets out a timetable for the phase-out of production and consumption of these chemicals.
The timetable set by the Montreal Protocol applies to the consumption of ozone-depleting substances only. To be clear, consumption encompasses the number of ozone-depleting substances produced minus those that are exported in any given year. Those that are destroyed are also deducted from the total number of ozone-depleting substances consumed. Percentage reductions are derived from the designated baseline year for a specific ozone-depleting substance. The protocol does not forbid the use of existing or recycled substances despite exceeding their phase-out dates.
There are exceptions for essential uses in cases where there are no available substitutes. Metered-dose inhalers and Halon fire suppression systems contain ozone-depleting substances. But since there are no viable alternatives for them, the Montreal Protocol has continued its use.
The United Nations General Assembly proclaimed the 16th of September as the International Day for the Preservation of the Ozone Layer as a way of commemorating the date at which the Montreal Protocol on Substances was signed.
Implementation of the Montreal Protocol progressed well in both developed and developing countries. Most of the phase-out schedules set by this protocol have been adhered to, some of them were even phased out in advance. Initially, the focus of the Montreal Protocol was chemicals with high ozone-depletion potentials which include CFCs and halons. The phase-out schedule for HCFCs was relaxed because they are used as a substitute for CFCs that have a lower ozone-depletion potential.
HCFC, according to the Montreal Protocol, should be phased out in 1992 for both developed and developing countries. The developed countries decided to move the phase-out of HCFCs to 2030. Developing countries agreed to move back the phase-out to 2040.
Clean Air and Sustainable Development Goals
According to the outcome document of the United Nations Conference on Sustainable Development entitled “The future we want”, member countries of the United Nations are committed to promoting sustainable development policies that support healthy air quality through sustainable cities and human settlements. Aside from that, the 2030 Agenda for Sustainable Development led to the recognition that pollution abatement is important to the attainment of the Sustainable Development Goals. Moreover, a road map to achieving sustainable development, environmental protection and prosperity for all were outlined in the 2030 Agenda for Sustainable Development.
The World Health Organization constantly monitors and tracks progress on health indicators to measure progress towards achieving Sustainable Development Goals that are relevant to ambient and household air pollution.
SDG target 3.9.1. Mortality Rate Attributed to Ambient Air Pollution
This SDG calls for a significant reduction in deaths and illnesses that are caused by air pollution. Since this falls under SDG 3, the broader goal is to ensure healthy lives and promote well-being for all of all ages. The goal is to substantially reduce the number of deaths and illnesses from hazardous chemicals and air, water and soil pollution contamination by 2030.
This SDG has a Tier I Classification. This means that the indicators for this Sustainable Development Growth are conceptually clear. Aside from that, internationally established methodology and standards are available, and data are regularly produced by countries for at least 50 percent of countries and of the population in every region where the indicator is relevant.
The mortality rate attributed to ambient air pollution can be expressed statistically as the Number of Deaths or Death rate. Death rates are calculated by dividing the number of deaths by the total population or the population group may be specified based on various parameters such as age or gender.
Epidemiological studies have provided evidence that exposure to air pollution is linked to several important diseases including acute respiratory infections in young children about 5 years of age and below, cerebrovascular diseases in adults ages 25 and above, ischaemic heart diseases in adults ages 25 and above, chronic obstructive pulmonary disease in adults ages 25 and above, and Lung cancer in adults ages 25 and above.
Several sources of air pollutants were assessed. These sources of air pollutants would result in either ambient or outdoor air pollution and household or indoor air pollution. Emissions from industrial activity, households, cars and trucks are complex mixtures of air pollutants, many of which are harmful to health. These constitute ambient or outdoor air pollution. Household or indoor air pollution may come from using kerosene, wood, coal, animal dung, charcoal, and crop wastes.
SDG target 7.1.2. Population with Primary Reliance on Clean Fuels and Technology
This Sustainable Development Goal aims to ensure access to clean energy in homes. This falls in line with the overall objective of SDG 7 which is to ensure access to affordable, reliable, sustainable and modern energy for all by 2030. This SDG falls under the Tier I classification as well.
The proportion of the population that relies on clean fuels and technology is calculated as the number of people using clean fuels and technologies for cooking, heating, and lighting, divided by the total population that uses any other fuels and technologies for cooking, heating, or lighting. Finally, it is multiplied by 100 and expressed as a percentage. “Clean” fuels and technologies are named as such because their emission rate is low enough to meet the WHO’s guidelines.
Data about the primary fuel used for cooking, categorized as solid or nonsolid fuels, where solid fuels are considered polluting and non-modern, while non-solid fuels are considered clean are still being collected globally. A single data collection captures a good part of the lack of access to clean cooking fuels. However, a single data collection does not include data on the type of device or technology that is used for cooking. Moreover, data on the type of device or technology that is used for cooking and the other polluting forms of energy use in the home such as those used for lighting and heating are excluded as well.
The book “WHO Guidelines for indoor air quality guidelines: household fuel combustion” emphasizes the importance of addressing both fuel and the technology for adequately protecting public health. These guidelines offer technical recommendations in the form of emission targets and on what fuels and technology combinations in the home are considered “clean”. According to this book, unprocessed coal and kerosene are discouraged for domestic use. Efficient fuels and technology combinations, such as solar, electric, biogas, natural gas, liquefied petroleum gas or LPG, and alcohol fuels including ethanol, on the other hand, are highly recommended for all major household energy and uses. This clarifies the technical recommendations in the WHO guidelines. The modern cooking solution in the home does not mean “access to non-solid fuels”. Instead, it means “access to clean fuels and technologies”.
Regardless of whether a country is low-income or middle income, a large part of household energy use is for cooking, lighting, and heating. In low-income countries, most households typically rely on solid fuels such as wood, charcoal, biomass, or kerosene paired with other inefficient technologies like open fires, stoves, space heaters or lamps. Several scientific studies have demonstrated that relying on inefficient energy for cooking, heating, and lighting leads to high levels of household or indoor air pollution.
It is estimated that over 4 million deaths annually, mainly among women and children, are linked to the usage of inefficient fuels for cooking. This estimated number of deaths is greater than Tuberculosis, HIV, and Malaria combined. Adopting cleaner fuels and technologies for household energy use can prevent death from exposure to indoor air pollutants. Aside from adopting cleaner fuels and technologies such as advanced combustion cookstoves, strict protocols for their safe use should be followed.
Realizing that clean and safe household energy use is a human development issue, universal access to energy encompasses access to both electricity and clean fuels and technologies for cooking, heating and lighting. Since that is the case, the UN Secretary General’s Sustainable Energy for All initiative now includes universal access to clean cooking
SDG target 11.6.2. Annual Mean Levels of Fine Particulate Matter (PM2.5) in Urban Areas
This Sustainable Development Goal aims to reduce the environmental impact of cities by improving air quality. The broader objective of SDG 11 is to make cities and human settlements inclusive, safe, resilient and sustainable. SDG 11.6 narrows down the goal to reducing the adverse per capita environmental impact of cities by paying special attention to air quality and municipal and other waste management systems. This SDG has a Tier Classification of Tier I.
Air pollution can be expressed as the annual concentration of fine suspended particles of less than 2.5 microns in diameters or PM2.5. The mean is a population-weighted average for the urban population in a country and is expressed in micrograms per cubic meter.
Particulate matter is one of many air pollutants. They are dangerous because they are capable of penetrating deep into the respiratory tract. Due to this property, particulate matter can increase mortality from respiratory infections and diseases, lung cancer, and some cardiovascular diseases.
There are some hurdles in tackling SDG target 11.6.2. The definition of urban or rural varies greatly from country to country. Moreover, the data quality available is relatively poor for some low- and middle-income areas.
The World Health Organization developed a database to track energy use for cooking, heating, and lighting, all over the world. This is used to measure the world’s progress towards achieving Sustainable Development Goal 7. To fill this database with information, the World Health Organization uses ground measurements, satellite data, chemical transport models, and population information to derive the population-weighted concentration of particulate matter. These pieces of information are used to report SDG 11 on annual air pollution in cities. The World Health Organization is and will continue to produce data and statistics for tracking these indicators on a regular basis.
The World Health Organization has partnered up with the UN Sustainable Energy for All Initiative or SE4ALL to ensure that shifts to cleaner household and health sector energy sources are taken into account in the SE4ALL’s tracking mechanisms of country-level indicators to measure progress toward SDG 7.
Cleaner air equals better Water Quality
European countries, especially Scandanavia, have been researching the effects of air pollution on water quality for several decades. In recent years, the United States and Canada joined in on the effort and conducted several research studies. Air pollutants with a substantial effect on water quality can be divided into four categories including trace metals, nutrients, toxic organic compounds, and airborne acids.
An overwhelming majority of studies regarding air pollution’s effect on water quality reveals that the atmosphere can, in fact, be a significant source of pollutant input to water. Despite this, problems with sampling methodology and a total absence of interagency project coordination limit the development of continuous databases that provide statistically significant data. So far, the exchange of information and cooperation between governments and nations has been good. However, there are too many small-scale research studies that are being funded by various agencies. There is a lack of large-scale studies which may offer valuable insights.
A survey on studies regarding the effects of air pollutants on water quality which was published by PEDCo Environmental concludes that expanded research is necessary to accomplish the following specific tasks:
Identify the sources of the pollutants and their relative source contribution to the total pollutant impact on water.
Improve technology for sampling the dry deposition of pollutants onto water surfaces.
Expand the database through expanding the geographical coverage of precipitation chemistry networks and through more long-range studies of specific watersheds.
Determine cross-media impacts, including direct impacts of air pollutants on water and the indirect impact of air pollution control technology on water quality.
Expand research to define the effects of pollutants on aquatic life forms and to determine the mechanisms of those effects.
It is well known by researchers that there is insufficient data about the impact of atmospheric trace metals on water. However, this lack of data is taken into account so that reasonable predictions on the impact of atmospheric trace metals on the water in any geographic location are still possible. Although there is no hard evidence yet, there is presumptive evidence that demonstrates that the air itself is a significant source of trace metals in some water systems. In the United States, several research studies on the impact of atmospheric trace metals on the water quality of Lake Michigan and Lake Washington Watershed in Tennessee were conducted. All of these studies presented a similar conclusion which is that the atmosphere could be a primary source of input for at least nine trace metals into the lakes.
Trace metals present in the atmosphere can increase trace metals present in water bodies. However, the effect of elevated trace metals on the water bodies’ biota is still not fully understood. The well-accepted theory is that high levels of trace metals are toxic at acid pH. More research is required to define excess concentrations and to determine the mechanisms of toxicity.
Even if the effects of trace metals in water are not fully understood, it pays to be careful. There are ways to control the amount of trace metals that are released into the atmosphere. For instance, effective emission controls can be applied to fossil-fuel-burning installations. Studies show that trace metals are concentrated during the combustion process and that a significant amount of these metals are included in the particulate fractions that escape electrostatic precipitators. There are studies that suggest the use of metal capture by sorbents because it is more effective in eliminating certain trace metals.
There are natural processes that force lakes to turn from oligotrophic or nutrient-poor to eutrophic or nutrient-rich. Human activities have accelerated the eutrophication process at a faster rate than the natural process. This led to an overabundance of nutrients and the subsequent stimulation of life cycles and depletion of oxygen within the eutrophic or nutrient-rich lake.
Nutrients such as nitrogen and phosphorus are the most frequently studied and well-understood nutrients. According to several studies, precipitation is a significant source of nitrogen in surface water. However, they are a less significant source of phosphorus. There are other studies that show that precipitation is not a significant source of either nitrogen or phosphorus to the water systems studied. Increased industrial or agricultural activity seems to increase the atmospheric input of nutrients to the water.
Toxic Organic Compounds
There are several toxic organic compounds but the ones often cited include polychlorinated biphenyl pesticides, and more recently, nitrosamines. There is incomplete knowledge regarding the mechanisms of toxicity of toxic organic compounds. Despite this, Polychlorinated biphenyl pesticides (PCBs) and dichlorodiphenyltrichloroethane (DDT) have been implicated as causative agents of cancer. These organic compounds can bioconcentrate in aquatic organisms including fish. Thus, they present a hazard to humans.
There is limited literature with regards to the effect of Toxic Organic Compounds on water bodies. One study investigated the sources of PCB input to the Southern California Bight. In this study, researchers provided evidence that the atmosphere is at least as significant as municipal wastewater systems as a source of PCB.
Among the air pollutant categories, airborne acids are the pollutants that are well understood because a good amount of literature concerning them is available. Several countries including Europe, the United States, and Canada, studied acid precipitation and their results show that there is a strong relationship between increased acidity of precipitation and atmospheric pollutants released from fossil-fuel combustion. Studies on the pH of precipitation in the northern areas of the United States revealed that the pH of precipitation ranges between 4.0 to 4.2 on average. Extremely low pH values of 2.1 have been reported during isolated storms. Studies conducted in Europe, particularly in Norway, revealed that there is a relationship between drops in the pH of precipitation and the level of fossil fuel usage.
The effects of changes in pH on aquatic ecosystems are not fully understood. However, most researchers and experts believe that low pH may have a negative effect on the metabolism of aquatic organisms. Moreover, low pH levels may enhance the toxicity of trace metals.
All of the studies surveyed by PEDCo Environmental generally agree that there is atmospheric loading of various air pollutants into water bodies. The study also revealed that there is a select number of air pollutants that can affect water quality significantly. Moreover, there are air pollutants that enter from the atmosphere and into water bodies but it is not fully understood whether or not they would affect water quality. With that said we could surmise that by reducing air pollutants, we would not only improve air quality but also water quality.