Qualité de l’air à Roseburg

Is Roseburg a polluted city?

Roseburg is a city located in the Umpqua River Valley, an area within the southern region of the state of Oregon. Roseburg is home to some 21,000 inhabitants as per a census conducted in 2010 and is estimated to have around 23,479 people living there as of 2019. Roseburg is also the seat of Douglas County, one of 36 counties within Oregon.

In regards to its air quality, Roseburg can have extremely clean air throughout much of the year, but the opposite is also true, specifically in regards to certain months, which will be discussed in further detail later in the article (as to which months have the highest chance of being polluted and the reasons behind them, mainly in order for residents to prepare or safeguard themselves from the volatile effects that pollution exposure has on one’s health). Looking at the air quality records from 2020, it can be seen that Roseburg had many of its months fall within the World Health Organization's (WHO's) target goal for the best quality of air (using PM2.5 as a measurement, which is recorded in micrograms per cubic meter, or μg/m³) at 10 μg/m³ or less. However, there were also several months, and one in particular, whereby the PM2.5 readings skyrocketed and caused the air to be highly dangerous to breathe for extended periods of time.

PM2.5 is one of the most dangerous pollutants that can be found in the air throughout Roseburg, and indeed in the United States and the rest of the world. Its minute size of 2.5 micrometers or less, as well as the materials that it is comprised of, give it this dangerous quality. Some of these materials include ones such as metals, sulfates, nitrates, soot, dust particles, finely ground silica or gravel, water vapor and other liquids, mold spores and bacteria. Due to being 2.5 micrometers or less (on occasion going down to sizes many microns smaller), it can bypass the body's defense systems and penetrate deep into the tissue of the lungs, causing a myriad of health issues.

Another air quality measurement is the US AQI reading, which itself is a number aggregated from the various main pollutants found in the air in Roseburg, of which PM2.5 is one. Other pollutants used in the calculation of the US AQI reading are carbon monoxide (CO), sulfur dioxide (SO₂), nitrogen dioxide (NO₂), ozone (O₃) and the two main forms of particle pollution, PM10 and PM2.5. PM10 is the larger or more coarse variety of particle pollution, and whilst it can cause irritation to exposed mucous membranes, chest pain and coughs, as well as potentially aggravating preexisting conditions, it still stands to reason that as the particle size becomes smaller, the level of danger that it presents to an individuals health grows all the more.

Referring to some up-to-date US AQI readings, taken in mid to late 2021, it can be seen that in August (2021), Roseburg presented with a US AQI reading of 248. This is an excessively high number, one that would classify the city of Roseburg as being ‘very unhealthy’ for the particular day and time in which it was taken. Days before this also came in with large elevations in the pollution levels, although it can be seen that in the months preceding this, the air quality was actually at a very optimal level. This leads back to the aforementioned point that Roseburg can have extremely good levels of air quality, but due to certain circumstances, such as the advent of wild or forest fires, the PM2.5 count and US AQI readings can go up to extremely high numbers, and with the 'very unhealthy' rating bracket being hit, as the name suggests, the entire population would be at high risk from the number of chemical compounds, fine particles and other air contaminants present in the atmosphere throughout Roseburg and also many other cities in the state.

What causes Roseburg to have such high levels of air pollution?

As mentioned, the largest contributor to air pollution levels in Roseburg would be that of forest fires. The burning of vast swathes of organic material, both dead and alive, can release highly dangerous pollutants into the air, which can cause further damage to the environment and ecosystems, as well as human health. This is true for the latter part of 2020, as well as early August of 2021 seeing sudden spikes in its US AQI readings, indicating the arrival of further wildfires.

To go beyond these causes, Roseburg, like many other cities throughout the United States, would also have other ambient sources of air pollution that contribute to raising the US AQI and PM2.5 levels over the course of the year. These include ones such as fumes and emissions released from vehicles, with the combustion of fuel in engines leading to large amounts of chemical pollutants and fine particles being released. This is particularly salient if the vehicle is a larger freight model, which includes trucks, lorries and certain buses. These often run on diesel fuel, the combustion of which releases higher amounts of pollution. Furthermore, the residual wear and tear of tire treads are also responsible for putting high quantities of microscopic rubber particles into the air, as well as contaminating bodies of water and soil, which can affect the growth of vegetation, and even make its way into the food chain due to the prevalence of said particles in the environment, and their incredibly small size making them easy to ingest amongst a variety of wild animals.

Other causes of air pollution include emissions from factories, power plants and other industrial sites, all of which utilize fossil fuels such as diesel, natural gas, oil and coal. Certain factories can give off their unique industrial effluence, which includes heavy metals such as mercury, lead and cadmium, along with polycyclic aromatic hydrocarbons, as well as dioxins and furans. Of note is that stricter regulations in North America ensure that the release of such contaminants is not as prevalent as it may be in countries with fewer regulations in place.

Other sources include construction sites and demolition areas, both of which can release large amounts of ultrafine or coarse particles, particularly if certain elements are not properly maintained (such as uncovered piles of sand, or inadequate washing of construction areas where large amounts of dust from cement and other materials can build up. In closing, Roseburg still has a majority of its pollution spikes coming from wildfires, with even one or two months of such occurrences giving the city a significantly poorer rating on the global circuit than it should have.

What health problems can arise from pollution exposure in Roseburg?

Health issues that may arise during periods of higher pollution include irritation to the respiratory tract, as well as the eyes, mouth, nose and ears. Skin conditions may arise, along with the aggravation of pre-existing conditions, typically those that fall under the chronic obstructive pulmonary disease (COPD) bracket. These include bronchitis, emphysema and asthma.

In more severe cases, high levels of pollution exposure lead to increased risks of strokes, heart attacks, arrhythmias, ischemic heart disease, as well as death.

When is the air the least safe to breathe in Roseburg?

Observing the PM2.5 levels that were recorded throughout 2020, it can be seen that Roseburg had a few months whereby the pollution levels rose significantly. Whilst much of the year came in within the WHO's target goal of 10 μg/m³ or less, the months of September through to December had considerably higher readings, making the last third of the year in Roseburg the most dangerous in terms of air cleanliness levels and possible health issues incurred from potential exposure during such times. Many studies show that high pollution levels, as well as an individual’s exposure (with the severity as well as the length of exposure being taken into consideration) having a direct correlation to higher rates of cancer, cardiac issues and death, with these deaths being directly linked to pollution exposure or resulting ailments that arise from said exposure.

The readings present from September through to December of 2020 were 80.5 μg/m³, 12 μg/m³, 11.4 μg/m³ and 15.1 μg/m³. This placed September well into the most polluted month of the year position, having a PM2.5 reading that classified it as being 'unhealthy', which requires a PM2.5 figure of anywhere between 55.5 to 150.4 μg/m³. This is many times higher than the cleanest months of the year, and even other relatively polluted months came in way below such a reading. This indicates the presence of a wildfire, which are the main causes of extremes in PM2.5 readings, as no amount of industrial or anthropogenic activity present in North America can give rise to such high levels of air pollution, although they may well indeed contribute to it, especially the year-round ambient pollution levels.

During 'unhealthy' periods of air quality, there will be a highly increased chance that adverse effects will occur, amongst all members of the population. As per usual, those with a vulnerable disposition will be even more gravely affected. Cardiac and pulmonary aggravation will become commonplace, and as such preventative measures should be employed, with all of the guidelines mentioned in the above questions being of great assistance.

After the extreme high of 80.5 μg/m³ abated, the following month of October had a reading of 12 μg/m³, which placed October within the 'good' air quality rating bracket. This requires a PM2.5 reading of anywhere between 10 to 12 to be classified as such, making for a fine margin of entry. Whilst the air quality during such time is nowhere near as severe in nature as the prior month, it indicates a movement towards higher pollution levels. The general public will still be free to conduct their daily activities during such times, but once again those with pre-existing health conditions or sensitive dispositions towards chemical or particle exposure will find themselves potentially having mild aggravation of their conditions and irritation of the respiratory tract or mucous membranes.

November had a mildly better reading of 11.4 μg/m³, still placing it within the 'good' air quality rating bracket. The final month of the year, however, showed a mild resurgence in air pollution, placing it in the 'moderate' air pollution rating bracket, the only month of the year to achieve such a rating. It came in with this 'moderate' rating with a PM2.5 reading of 15.1 μg/m³, with a 'moderate' classification requiring a PM2.5 figure of anywhere between 12.1 to 35.4 μg/m³ to be named as such.

At such levels, sensitive or at-risk individuals should start to avoid outdoor activity in order to prevent any unwanted or negative side effects. Mild aggravation may also start to present itself in otherwise healthy individuals. In closing, it can be seen from the 2020 records that the last quarter of the year is the period in which Roseburg was at its most heavily polluted, and although this was largely due to the advent of forest fires heavily skewing the readings, it can also be an indicator that the pollution levels could potentially rise in the last third of the year, with or without the large spikes in PM2.5 that come directly from fires. Roseburg had a yearly PM2.5 reading of 12 μg/m³, which again placed it into the 'good' air quality rating bracket, as well as placing it in 1850^th place out of all cities ranked worldwide for 2020.

When is the air safest to breathe in Roseburg?

Continuing on from air quality records collected over the course of 2020, it can be seen that the months of January through to August all had the most optimal levels of air quality, all of them coming in within the WHO's target goal of 10 μg/m³ or less, indicating a significantly cleaner period of time in which the air was free from large amounts of smoke, haze, clouds of fine particles and other contaminating agents.

The respective readings of these months were 5.4 μg/m³, 8.3 μg/m³, 5.5 μg/m³, 4.4 μg/m³, 3.6 μg/m³, 3.2 μg/m³, and 4.6 μg/m³ for both July and August. This placed May and June into the cleanest spots for the entire year with their readings of 3.6 μg/m³ and 3.2 μg/m³, very respectable levels of air quality.