Qualité de l’air à St. Paul

What is the current level of air pollution in Saint Paul?

Saint Paul (abbreviated St. Paul) is the capital of the U.S. state of Minnesota. According to the 2010 census, Saint Paul had an estimated population of approximately 285,000 people, however, a revised figure in 2019 estimated it to be 308,000 inhabitants.

Towards the middle of 2021, Saint Paul was enjoying “Good” quality air with a US AQI reading of 31. This United States Air Quality Index number is an internationally used set of metrics supported by the World Health Organisation (WHO) and is used to compare the air quality in different cities throughout the world using comparable standards. It is calculated by using the levels of the six most commonly found pollutants. If records are not available for all six, then a figure is calculated using what information is available. In the case of Saint Paul, only PM2.5 was recorded with a reading of 7.6 µg/m³. With a relatively low level such as this, doors and windows can be opened to allow the fresh air to enter the rooms. All forms of outdoor activities can be enjoyed without fear of breathing in polluted air.

Does the level of air quality vary throughout the year in Saint Paul?

Air pollution can be very volatile and, as such, can change very quickly depending on many variables, such as wind speed and direction and the strength of sunlight, as well as during the different seasons of the year.

Looking back at the figures published by IQAir over the course of 2020, it can be seen that from March until the end of November, Saint Paul achieved the target figure as recommended by the World Health Organisation (WHO). This figure should be less than 10 µg/m³. The best figure attained was during September when the figure was 6.7 µg/m³. The level in February was classified as being “Good” with a reading of 10.8 µg/m³. The remaining two months of December and January saw a slight decline with the quality of air being “Moderate” with respective figures of 12.3 µg/m³ and 12.5 µg/m³.

Figures were first kept in 2017 when Saint Paul achieved the WHO target figure with a reading of 7.5 µg/m³. The following year saw a similar result with a reading of 8.2 µg/m³. For 2019 and 2020 the figures were as follows: 9.5 µg/m³ and 9.1 µg/m³. However, the 2020 result may not be a true reflection of reality due to the restrictions imposed because of the COVID-19 pandemic. Many vehicles were no longer used as their drivers were furloughed and not required to commute to and from work. There were also many factories and other non-essential production units which were temporarily closed in an attempt to prevent the spread of the virus.

What has been done over the last few years to improve the air quality in Saint Paul?

Over the past 30 years, the Clean Air Act has resulted in major reductions in air pollution across the entire country. This was achieved through strict controls over the largest polluters which were vehicles and boilers. New regulations on the sources have made a big difference and helped Minnesota to become better than all national standards and health benchmarks.

The Clean Air Act requires the U.S. Environmental Protection Agency (EPA) to set National Ambient Air Quality Standards for pollutants that are considered both harmful to public health and to the environment. The EPA sets standards for six common air pollutants — ozone, fine particles (PM), lead, nitrogen dioxide, carbon monoxide, and sulfur dioxide.

Air toxins are a group of over 100 pollutants that may cause cancer or other serious health effects. There are no enforceable standards for most of these chemicals so Minnesota relies on guidelines and devises benchmarks to evaluate the risks to public health.

What are the main sources of the polluted air in Saint Paul?

Most of the air pollution in Minnesota comes from smaller, more widespread sources such as industrial facilities including power stations and refineries. Vehicles such as cars and trucks and portable equipment such as lawnmowers etc. are powered by gasoline engines, together with construction equipment, trains and airplanes. The rearing of livestock and domestic wood-burning stoves are also part of the problem.

Electricity production and transportation, have reduced pollution due to government regulations and stricter controls but agricultural and residential sources are mainly ignored.

Researchers focused on one harmful pollutant: fine particulate matter, also known as PM2.5, which is associated with heart attacks, strokes, lung cancer and other diseases. In examining the data, they discovered that about half of all PM2.5 air pollution-related deaths are from burning fossil fuels, with the remainder coming largely from animal husbandry, dust from construction and roads and burning wood for heating and cooking.

It must be noted that some of the worst pollutants are now generated outside the state and carried in by the wind from events such as wildfires in Canada and the Pacific Northwest. This will need interstate cooperation before this situation can be rectified.

To what extent does air pollution affect the residents of Saint Paul?

Air pollution contributes to as many as 10 percent of all deaths in Minnesota every year, whilst being responsible for sending almost 1,300 people to the hospital with heart and lung problems. The problem is not confined to the urban areas in Minnesota but to the rural areas as well. Going back as far as 2015, an intense study was conducted and discovered that the two most common pollutants were PM2.5 and ozone (O₃) and that they were responsible for around 2,000 deaths in the metropolitan area.

The situation is improving with the closure of coal-fired power stations or their conversion to cleaner fuels such as gas, but pollution is on the rise in some areas such as industrial plants and household sources. Even seemingly innocuous activities such as mowing the lawn or having a barbeque produce air pollutants.

What is the Air Quality Index and how does it help the residents of Saint Paul?

The Air Quality Index, or AQI, is the system used to warn the public when air pollution is at dangerous levels. It measures the levels of ozone and small particulate matter (PM2.5) as well as the other major sources of air pollution. Ash, power plants and factories emissions, vehicle exhaust fumes, fine soil, pollen and other pollution. Once the figures are seen to be higher than average, a warning is issued via the media such as newspapers, radio, television and websites. Knowing how polluted the air is should help you decide what to do during the day to stay safe.

What is PM2.5 and why is it important in Saint Paul?

To help understand which communities breathe the highest concentrations of this dangerous air pollution, a model was used to estimate the amount of fine particulate matter (known as PM2.5) produced by on-road vehicles that burn gasoline and diesel. Those who are the most susceptible to pollution are those who live near main roads, along major freight corridors, and in urban areas.

PM2.5 includes particles smaller than 2.5 millionths of a meter in diameter – about 30 times smaller than the diameter of fine human hair — so they can penetrate deeply into the lungs. The ultrafine particles – smaller than 0.1 millionth of a meter – are particularly dangerous, as they lodge in the alveoli and eventually enter into the bloodstream. Exposure to such particles can affect both your lungs and your heart.

Particulate Matter is a complex mixture that may contain soot, smoke, metals, nitrates, sulfates, dust, water and tire rubber. It can be directly emitted, as in smoke from a fire, or it can form in the atmosphere from reactions of gases such as nitrogen oxides.

Long-term exposure to particulate pollution can result in significant health problems including increased respiratory symptoms, such as irritation of the airways, coughing or difficulty breathing. A decrease in the function of the lungs and aggravated asthma. The development of chronic bronchitis or chronic obstructive lung disease and chronic respiratory disease in children. Premature death in people with heart or lung disease, including death from lung cancer.

What can be done to reduce air pollution in Saint Paul?

• Educate and reach out to haulage companies to reduce engine idling.
• Create incentives or subsidies for retrofitting and rebuilding diesel engines to reduce emissions.
• Educate users of stationary diesel generators about their exhaust fumes.
• Retire high-emitting vehicles.
• Plant trees in cities to improve air quality and mitigate the "urban heat island" effect.
• Establish a grant program for alternative fuel infrastructures like natural gas fuelling and electric charging stations.
• Establish incentives for fleets that use alternative fuels
• Expand electric vehicle use and infrastructure to support it.
• Exchange wood stove and fireplaces for gas ones.
• LEducate and reach out to people about reducing wood smoke.

There is a boat that is used for helping boats up and down the Mississippi River that has had its two old diesel engines replaced by modern ones which are much more efficient and produce less pollution. This will prevent more than 20 tons of air pollution generated each year. It equates to removing some 12,000 cars off the city’s streets.

This led to the retrofitting of over 5,000 publically owned vehicles including more than 200 school buses.

What are the health and environmental effects of air pollution?

Air pollution is now the biggest environmental risk for early death, responsible for more than 6 million premature deaths each year from heart attacks, strokes, diabetes and respiratory diseases. That’s more than the deaths from AIDS, tuberculosis and malaria combined.

Air pollution can harm us when it accumulates in the air in high enough concentrations. Millions of Americans live in areas where urban smog, fine particle pollution, and toxic pollutants pose serious health concerns. People exposed to high enough levels of certain air pollutants may experience irritation to the eyes, nose and throat. This may lead to wheezing, coughing, chest tightness and breathing difficulties. Existing respiratory conditions will worsen under these conditions and the risk of a heart attack will increase.

In addition, long-term exposure to air pollution can cause cancer and damage to the immune, neurological, reproductive, and respiratory systems. In extreme cases, it can even cause premature death.

Even strong, healthy people can experience health impacts from polluted air including respiratory irritation or breathing difficulties especially during exercise or outdoor activities. The actual risk of adverse effects depends on the current health status, the pollutant type and concentration, and the length of exposure to the polluted air.

High levels of air pollution can cause immediate effects and health problems such as aggravated cardiovascular and respiratory illnesses. It adds stress to the lungs and heart as they have to work so much harder in order to supply the required amount of oxygen to the body. Cells within the respiratory system can soon become damaged.

Certain groups of people will be affected more severely than others. Those individuals with pre-existing heart disease and those with lung diseases such as asthma, emphysema or chronic obstructive pulmonary disease (COPD) will feel the effects long before healthy people. Pregnant women, children under the age of 14 years, senior citizens and those who work outdoors for most of the day will be the most affected.

Acid rain is precipitation containing harmful amounts of nitric and sulphuric acids. These acids are formed primarily by nitrogen oxides and sulfur oxides released into the atmosphere when fossil fuels are burned. They can damage trees and cause soil and water to become acidic and therefore unsuitable for supporting growth. It can also speed up the decay of buildings and statues and similar monuments.

Acid rain, climate change and smog all damage the Earth’s surface. Contaminated water and gases seep into the earth, changing the composition of soils. That directly affects agriculture, changing crop cycles and the composition of the food we all eat.

Smog can be many types of pollutants and can be of 2 types: sulfurous smog and photochemical smog, both dangerous and harmful to health. Sulfurous smog has its origin mainly in the use of coal in many industrial processes. However, due to the fact that coal-fired power stations are in a slight decline, the situation is getting better.